Coenzyme Q10 and ubiquinol for physical performance

Abstract

The effect of coenzyme Q10 (CoQ10) supplementation on physical performance has long been a controversial subject. There have been several studies that have demonstrated a beneficial effect of CoQ10 on sports performance whereas many others have been neutral. It has been difficult to interpret the multiple studies due to three main factors: the formulation of CoQ10 administered, its dosage and duration of administration; the wide variety of subjects enrolled in the studies ranging from untrained individuals to elite athletes including weight lifters and marathon runners; the wide variety of methods of assessing physical performance including work performed, either acute performance, endurance exercise or time to exhaustion. We have reviewed 28 studies ranging over a 25 year period. We have critically analysed the results and have reviewed the possible mechanisms of action. The results showed that the studies were more likely to show a beneficial effect if: the CoQ10 preparation was more readily bioavailable especially if it was administered in the reduced form (ubiquinol) rather than oxidised form (ubiquinone); was given at high dosage 300 mg per day or more, for a period of two to three to months; where the exercise performed was peak performance such as sprinting or weight lifting and where the method of assessment of performance was physical work output rather than long lasting endurance exercise. We conclude that coenzyme Q10 and especially ubiquinol can have a beneficial effect on physical performance provided it is given in an appropriate form, adequate dosage and time of administration and where performance is assessed using a reliable and reproducible accurate measure of work output. © The effect of coenzyme Q10 (CoQ10) supplementation on physical performance has long been a controversial subject. There have been several studies that have demonstrated a beneficial effect of CoQ10 on sports performance whereas many others have been neutral. It has been difficult to interpret the multiple studies due to three main factors: the formulation of CoQ10 administered, its dosage and duration of administration; the wide variety of subjects enrolled in the studies ranging from untrained individuals to elite athletes including weight lifters and marathon runners; the wide variety of methods of assessing physical performance including work performed, either acute performance, endurance exercise or time to exhaustion. We have reviewed 28 studies ranging over a 25 year period. We have critically analysed the results and have reviewed the possible mechanisms of action. The results showed that the studies were more likely to show a beneficial effect if: the CoQ10 preparation was more readily bioavailable especially if it was administered in the reduced form (ubiquinol) rather than oxidised form (ubiquinone); was given at high dosage 300 mg per day or more, for a period of two to three to months; where the exercise performed was peak performance such as sprinting or weight lifting and where the method of assessment of performance was physical work output rather than long lasting endurance exercise. We conclude that coenzyme Q10 and especially ubiquinol can have a beneficial effect on physical performance provided it is given in an appropriate form, adequate dosage and time of administration and where performance is assessed using a reliable and reproducible accurate measure of work output.

Full text

Chapter
COENZYME Q10 AND UBIQUINOL
FOR PHYSICAL PERFORMANCE
Stefan Siebrecht1, Darren Yak Leong Chan2,
Franklin Rosenfeld3 and Kenneth Weicong Lin3
1Consultant for Health Ingredients, Schwelm, Germany
2Department of Cardiothoracic Surgery, Alfred Hospital,
Melbourne, Australia
3Monash University, Melbourne, Australia
ABSTRACT
The effect of coenzyme Q10 (CoQ10) supplementation on physical
performance has long been a controversial subject. There have been
several studies that have demonstrated a beneficial effect of CoQ10 on
sports performance whereas many others have been neutral. It has been
difficult to interpret the multiple studies due to three main factors: the
formulation of CoQ10 administered, its dosage and duration of
administration; the wide variety of subjects enrolled in the studies ranging
from untrained individuals to elite athletes including weight lifters and
marathon runners; the wide variety of methods of assessing physical
performance including work performed, either acute performance,
endurance exercise or time to exhaustion. We have reviewed 28 studies
ranging over a 25 year period. We have critically analysed the results and
have reviewed the possible mechanisms of action. The results showed
that the studies were more likely to show a beneficial effect if: the CoQ10
preparation was more readily bioavailable especially if it was

Stefan Siebrecht, Darren Yak Leong Chan, Franklin Rosenfeld et al.
2
administered in the reduced form (ubiquinol) rather than oxidised form
(ubiquinone); was given at high dosage 300 mg per day or more, for a
period of two to three to months; where the exercise performed was peak
performance such as sprinting or weight lifting and where the method of
assessment of performance was physical work output rather than long
lasting endurance exercise. We conclude that coenzyme Q10 and
especially ubiquinol can have a beneficial effect on physical performance
provided it is given in an appropriate form, adequate dosage and time of
administration and where performance is assessed using a reliable and
reproducible accurate measure of work output.
Keywords: coenzyme Q10, ubiquinone, ubiquinol, dietary supplements,
athletes, physical performance, exercise, physical exertion, muscle
strength
INTRODUCTION
Coenzyme Q10 (CoQ10) is a fat soluble antioxidant and a vital component
of the mitochondrial respiratory chain for energy production. CoQ10 is the only
lipid-soluble antioxidant that is synthesized in human cells [1]. CoQ10 can
exist in an oxidised form (ubiquinone) or reduced form (ubiquinol). Virtually
every cell in the body contains CoQ10 with the highest concentration in organs
that have the highest energy requirements, such as heart, liver, kidney and
muscles [2, 3, 4]. The daily human requirement of CoQ10 is covered by a mix
of biosynthesis and dietary intake of which biosynthesis is more important [5].
A lower dietary intake of CoQ10, as well as a decrease of biosynthesis due to a
lower intake of nutrients essential for CoQ10 biosynthesis, or blocking of
CoQ10 biosynthesis by statin therapy can lead to decreased CoQ10 plasma and
tissue levels.
PHYSIOLOGICAL FUNCTIONS OF COQ10
The body contains around 2,000 mg of CoQ10 mainly located in
mitochondria. CoQ10 is essential for energy production in the mitochondria but
also functions as an antioxidant in cell membranes. CoQ10 plays an essential
role in oxidative phosphorylation via the respiratory transport chain for
mitochondrial ATP production. ATP is the energy molecule for all life
processes, generating 96% of the total aerobically generated energy [5, 6].

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3
During electron transport in the respiratory chain ubiquinol and ubiquinone are
continuously converted into each other. Ubiquinone and ubiquinol work as
catalysts and so are actually not consumed. Nevertheless, a small part of
CoQ10 is destroyed and lost every day. Therefore, CoQ10 must be synthesized
by the body or taken up from the daily diet. Body organs with a high energy
turnover especially heart and skeletal muscles depend on an adequate supply
of CoQ10. If these organs become deficient in CoQ10 they generate less energy
and power.
COQ10 AND UBIQUINOL IN SPORT NUTRITION
Influence of Exercise and Diet on Plasma Levels in Athletes
The human body contains about 2,000 mg of CoQ10. The normal CoQ10
plasma level of healthy people lies between 0.60 – 1 mg/l. The CoQ10 plasma
levels are easy to measure but actually not a good guide to the overall CoQ10
status of the body. The CoQ10 levels in the blood can greatly fluctuate and
often differ from the level in the tissues. Even if we find a normal CoQ10 level
in the blood there can be a decreased level in the tissues. However, the CoQ10
level in the blood is easy to determine and a low level in the blood is at least
an indication of a possible undersupply with CoQ10. A total body deficiency of
CoQ10 can show up as a decrease in the CoQ10 plasma level and give an
indication that the tissue levels of CoQ10 may be decreased.
Increased oxidative stress can lead to a reduction of CoQ10 plasma levels.
Hence people who are exposed to increased oxidative stress have lower CoQ10
plasma levels than healthy people [6]. In diseases such as diabetes or heart
disease, the CoQ10 plasma levels can fall by 60% to 70% to a value of 0.3 –
0.4 mg/l [7, 8]. The CoQ10 plasma level depends on many factors and may
vary greatly thus it would be useful for many people and especially athletes to
determine their personal CoQ10 plasma levels.
Regular, medium intense exercise over some weeks leads to an increase of
CoQ10 plasma levels in healthy humans as shown in a study with 28 male
leisure-time cyclists, aged between 30-50 years (39.7±6.6), with normal body
mass index (23.2±1.5) and good health. Their CoQ10 plasma levels were
around 0.79 mg/l, which is normal. After 8 weeks of training the CoQ10
plasma level increased to 1.14 mg/l, an increase of +44%. It was found that
supplementation with CoQ10 increased the CoQ10 plasma level from 0.78 mg/l

Stefan Siebrecht, Darren Yak Leong Chan, Franklin Rosenfeld et al.
4
to 2.22 mg/l and a session of acute exercise further increased CoQ10 in the
plasma to 2.38 mg/l (measured after exercise) [10].
On the other hand, excessive physical training and meatless diets can
lower CoQ10 plasma levels in athletes. Studies have shown that hard physical
training among athletes leads to a decrease of CoQ10 levels in the plasma
[11,12]. Also, a vegetarian or vegan diet leads to a lowering of the CoQ10
levels in the blood. Vegan or vegetarian living triathletes had the lowest CoQ10
levels of all analysed athletes [12]. Thus athletes and especially endurance
athletes should measure their plasma CoQ10 in the blood frequently. The
CoQ10 plasma level is dependent on many factors and can vary greatly, due to:
• Dietary composition (low fat content reduces the CoQ10 intake)
• Nutritional behaviour (vegetarian etc. result in lower CoQ10 intake
with food)
• Bad nutritional status (lack of selenium, B6, inhibits CoQ10
biosynthesis)
• High vitamin E supplements (inhibits CoQ10-intake)
• Statin therapy for hypercholesterinaemia (inhibits CoQ10 biosynthesis)
• Older age (lowers CoQ10 biosynthesis)
• Illness (higher oxidative stress increases the use of CoQ10)
• Sustained physical endurance and training (increases the use of
CoQ10)
PHYSICAL PERFORMANCE AND COQ10 AND
UBIQUINOL SUPPLEMENTATION
CoQ10 has been on the market for many years and is a popular dietary
supplement. It has been used in the past in sports nutrition and tested in many
clinical trials in athletes. Overall twenty eight studies of CoQ10
supplementation in sports have been published (Table 3). Of these, 26 studies
used the oxidized form of CoQ10 and only two more recent studies have been
conducted with the reduced form ubiquinol (QH). The athletes received
dosages between 30 - 300 mg CoQ10 or QH per day for periods of time from
10 days to 6 weeks. These studies showed no consistent results, which is not
surprising due to the many very different designs of the studies. Too low
dosages, an insufficient period of supplementation and often small sample
sizes are some of the reasons why some studies showed no effects and created

Coenzyme Q10 and Ubiquinol for Physical Performance
5
results conflicting with other studies that showed benefits. Furthermore, one of
the most important variations in these studies was the method of measuring
physical performance.
POTENTIAL REASONS FOR INCONCLUSIVE
STUDY RESULTS
Wrong Study Designs: General Remarks
We clearly have to state that is easier to design nutritional
supplementation studies that generate no results at all than to design a study
that creates positive results. There are many different parameters that
determine the outcome of such studies and one or more parameters that are
wrongly chosen can cause the failure of the whole study. Some of these
important parameters are: the chosen participants, age, sex, physical training
status; dosage of supplement; duration of the supplementation; chosen
measurement parameters; compliance of the patients; performance
measurement protocol; general diet and health status; chosen dosage form;
bioavailability of the nutrients e.t.c., and many more. In the case that the study
generates no results at all, this does not mean that the supplement is
inefficient. It just means in the first line, that the design of the study was
unable to show a benefit and or as another possibility, that the nutritional
supplement is potentially inefficient at all. Some scientist wait before they give
advice, until there are many studies published showing all consistent positive
result which is almost impossible, and doesn`t happen in reality. In most cases,
some studies show benefits and other studies do not. But: “No observed
effects” in a study are not the opposite of “positive observed effects”!
Nutritional supplements that have shown positive results in some studies,
demonstrate that the ingredient has the potential to be effective under certain
circumstances and that the design of the study is important to create positive
results. The term “mixed results” is often used when some nutritional studies
showed positive effects while others do not show any positive or negative
effects. In such cases a nutritional supplement has the potential to be effective,
depending on the chosen design. So in this case there is a possibility of a
positive benefit for people who consume the nutritional supplement. In this
case, the positive advice for trying the supplement might already be available
to consumers who want to investigate the benefits of the supplement. Some of

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6
the potential reasons that caused problems in showing clinical evidence for
CoQ10 in sport nutrition are:
Poor Absorption of Ubiquinone
A possible explanation for the failure of many studies in the field of
athletic performance and CoQ10 is that traditional CoQ10 is poorly absorbed
after oral ingestion [13]. This fact requires the use of higher dosages is
required for athletes to achieve the desired physiological effects. CoQ10 is
absorbed at a constant rate of 100 mg per 6.2 hours in the gastrointestinal tract.
In a study by Mohr et al single oral doses of 100 and 200 mg of CoQ10
supplement resulted in an increase of the total plasma CoQ10 levels of 80%
and 150%, respectively, within 6 hours. Long term supplementation with 300
mg CoQ10 per day for 11 days resulted in plasma levels of the CoQ103-5 fold
higher than before [14]. QH as a supplement has been newly developed
(Kaneka QH,) and has shown an advantage of a greatly improved
bioavailability. Hosoe et al. showed that after a single oral dose of 300mg of
QH a 4.7-times increase in the QH plasma levels was achieved [15]. After
regular daily administration of 300 mg QH for 28 days, a 10-fold increase in
plasma levels was achieved. Such an increase of plasma QH levels is far
greater after using QH, than was ever observed after supplementation with the
traditional CoQ10. So far QH has been used only in 2 of 29 studies in athletes.
Too Low Dosages of CoQ10
In most published studies the conventional poorly absorbed CoQ10 was
given at quite low dosages: 15 studies used 100mg or even less per day, 7
studies used dosages of 120 - 200 mg CoQ10 per day and 5 studies were using
either 300 mg CoQ10 or 300 mg ubiquinol (Table 3).
In the past the maximum daily dosage of CoQ10 in dietary supplements in
Europe and Germany was limited by regulation to 30 mg daily. Today in many
countries of the EU CoQ10 dosages of 100-200 mg per day have been
approved for dietary supplements for normal people. It is known from studies
of other nutrients that athletes often require higher dosages than normal people
due to a higher bodyweight and/or due to more intense training and
performance. This means that we do not know yet the optimal dosage for
ubiquinol for athletes. So far the maximum dosage used in athletes was 300

Coenzyme Q10 and Ubiquinol for Physical Performance
7
mg ubiquinol, whether this is already the optimal dosage or if some athletes
need and benefit from higher dosages than 300 mg ubiquinol is not known yet
and has to be evaluated by further studies. Especially as new studies with
higher doses of CoQ10 and ubiquinol show better effects in athletes.
Ubiquinol is an extremely potent antioxidant and the oxygen in the air will
quickly oxidise it. This was the main reason why it has not been possible to
produce QH and use it in a stable form in dietary and sports supplements.
Since the Japanese company Kaneka has succeeded in establishing a
process to produce QH in a stabilized form, ubiquinol is now available on the
market and can be used in the new studies in athletes. The increased use of
CoQ10 and QH in sport nutrition will depend on the number of new studies that
are done with the correct dosage and will hopefully show consistent results in
performance enhancement. In fact, so far all studies where athletes were given
higher dosages of 300 mg CoQ10 or QH per day show better results on
performance than lower dosages [16, 17, 18, 19] (Table 3). Incidentally, the
highest plasma CoQ10 concentration ever reported in the literature thus far is
10.7µmol/l (=9.23 mg/l). This was achieved using CoQ10 in the form of QH
[20]. Whether this represents a value close to a ceiling for plasma CoQ10 needs
to be established. Furthermore, it would be important to determine whether
such high plasma concentrations afford maximum therapeutic benefit [21].
The highest net increase in plasma CoQ10 concentration and also the highest
increase per 100 mg CoQ10 ingested was observed using solubilized CoQ10 as
QH at a dose of 600 mg and these values are higher than those obtained with
much larger doses of CoQ10 (up to 3,000 mg; [20]).
Too Low CoQ10 Plasma Level and Too Short Duration
of Supplementation
To compensate for a CoQ10 deficiency in the plasma and to bring levels
back to normal (0.8 - 1.0 mg/l) only small amounts of CoQ10 are needed. On
the other hand to achieve clinical effects, to enhance physical performance or
to treat a systemic tissue CoQ10 deficiency the CoQ10 plasma levels must be
greatly increased for a longer period of time so that the organs will have
sufficient time to replenish their CoQ10 pools and this happens quite slowly.
The target therapeutic CoQ10 plasma levels have been raised by experts over
the last 30 years. In the 1980s the target CoQ10 plasma level was around 1.5
mg/l and was increased in the 1990's to 2.5 mg/l [22]. Today the recommended
value of the plasma CoQ10 level is > 3.5mg/l or higher [22]. Studies in the past

Stefan Siebrecht, Darren Yak Leong Chan, Franklin Rosenfeld et al.
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linked the effectiveness of the CoQ10 supplementation principally to the CoQ10
plasma levels: the higher the plasma level, the better the effects. At this point
the bioavailability of the CoQ10 became the main barrier to increasing CoQ10
plasma levels to a maximum value. As a response to this, great strides were
made in improving the bioavailability of CoQ10 especially the development of
the much more bioavailable QH.
BIOAVAILABILITY OF UBIQUINOL AND UBIQUINONE
CoQ10 is fat soluble and as a result has first of all to be emulsified in the
watery medium of the intestine before being absorbed into the body. So its
bioavailability depends on the CoQ10 formulation and the method of uptake.
Fats, oils and emulsifying agents like lecithin increase the bioavailability of
CoQ10. CoQ10 is a crystalline powder that is insoluble in water. Absorption
follows the same process as that of lipids and the uptake mechanism appears to
be similar to that of vitamin E, another lipid-soluble nutrient. This means that
if taking high dosages the Vitamin E (for example 1000 mg) competes versus
CoQ10 for the absorption and this can decrease the absorption of CoQ10. [72].
The absorption process in the human body involves the secretion into the small
intestines of pancreatic enzymes and bile that facilitate emulsification and
micelle formation that is required for the absorption of lipophilic substances
[73]. Food intake (and the presence of lipids) stimulates bodily biliary
excretion of bile acids and greatly enhances the absorption of CoQ10.
Exogenous CoQ10 is absorbed from the small intestinal tract and is best
absorbed if it is taken with a meal. Serum concentration of CoQ10 in fed
condition is higher than in fasting conditions [74].
It has been clearly demonstrated that there is an almost linear relationship
between the CoQ10 plasma level and dosage up to around 200 - 300 mg a day
[23, 17] where it reaches a plateau. Humans appear to have a limited capacity
to absorb CoQ10. In studies with people suffering from Parkinson's disease, it
was only possible to achieve a plasma level of 6 mg/l with a 2,400-3,000 mg
dose [24]. Studies have shown QH is 2-4- times more bioavailable than the
conventional CoQ10. An oral dosage of 300 mg conventional CoQ10 achieves
plasma CoQ10 levels of around 3 mg/l [25] whereas the similar plasma levels
can already be achieved with 90 mg of QH [15] (Figure 1). Plasma levels of 6-
8 mg/l can be achieved in humans with 300 mg QH [17] (Figure 1). With 450
– 600 mg QH, CoQ10 plasma levels of 6-8 mg/l can be achieved [26].

Coenzyme Q10 and Ubiquinol for Physical Performance
9
Figure 1. Comparison of human CoQ10 plasma levels after supplementation with
ubiquinol (QH) or conventional ubiquinone (Q10).
The mechanism behind the higher bioavailability of QH versus the
traditional CoQ10 has not yet completely determined. Most probably, it is
because conventional oxidized CoQ10 must first react with the CoQ10-
reductase enzyme, where it is then reduced to ubiquinol, before it is
incorporated into lipoproteins, which are then released into the blood. QH as a
reduced form of CoQ10 is independent of this enzyme and can be immediately
incorporated into the lipoproteins and therefore quickly enter the bloodstream.
COQ10 PLASMA LEVELS IN HUMANS AND ATHLETES
QH is the preferred form of CoQ10 for transport in the blood plasma: 95%
of the CoQ10 transported in the plasma is in the reduced form. That might be
another reason for the better bioavailability of QH. So when we talk about
CoQ10 plasma levels we mostly talk about QH plasma levels. The optimal
plasma level of CoQ10 for athletes has yet to be elucidated and many questions
remain. Should athletes take CoQ10 supplements and what should their plasma
CoQ10 value be? Do athletes need more CoQ10 due to their higher physical
exertion? Is a normal, "healthy" plasma level of 1mg/l enough for athletes or
should athletes aim for the highest possible value of >3.5mg/l, for example?
Although CoQ10 actually acts a catalyst and is theoretically always
regenerated, it appears that a certain proportion of CoQ10 is lost during
sustained exertion, for example such as sports training [11]. Trained athletes

Stefan Siebrecht, Darren Yak Leong Chan, Franklin Rosenfeld et al.
10
often have lower CoQ10 plasma levels than untrained people [11, 12]. The
most likely reason for this is that athletes appear to have a greater requirement
for CoQ10 due to a higher CoQ10 consumption which is not fully covered by
normal food intake and biosynthesis in the body [27]. Highly trained athletes
can therefore have lower CoQ10 levels in tissue and blood [28] and this can
limit their performance. So it is especially important for athletes to monitor
their CoQ10 plasma level and to supplement their CoQ10 levels as necessary.
There is as yet no recommended CoQ10 plasma level for athletes. But the latest
studies show a link between the CoQ10 plasma level and performance capacity:
the higher the CoQ10 plasma level, the higher the performance capacity [17].
A Possible CoQ10 deficiency in athletes can be triggered by:
• Increased consumption/losses of CoQ10 due to increased oxidative
stress during physical exercise
• Reduced CoQ10 uptake due to vegetarian or vegan diet
• Limited CoQ10 biosynthesis due to nutrient deficiencies such as
selenium, vitamin B6, magnesium etc.
• Intake of high doses of vitamin E inhibiting CoQ10 uptake from food
and lowering CoQ10 plasma level
• Statin therapies limiting CoQ10 biosynthesis and lowering the CoQ10
plasma level
Dosages of CoQ10 and Ubiquinol for Athletes
Lowered CoQ10 plasma values can be normalized by supplementing with
small dosages of CoQ10 or QH (30 -100 mg per day). In contrast, it appears
that a dosage of 100 mg CoQ10 a day for athletes is too low to create a
performance-enhancing effect. It should also be pointed out that a few earlier
studies were unsuccessful because the CoQ10 plasma level could not be
increased sufficiently despite supplementation with 100 mg CoQ10 per day. In
an early Italian study, a dosage of 100 mg CoQ10 per day increased the plasma
level to a value of only 1.34 mg/l [29], which is too low to achieve any effect
for athletes.
In a later Italian study, it was possible to raise the CoQ10 plasma level to
2.23 mg/l using an improved CoQ10 formulation with the same dosage of 100
mg per day. After 2 months of CoQ10 supplements, muscles achieved greater
exertion before exhaustion and overall performance improved [30]. In a dose
finding study, a dose of 100 mg CoQ10 showed no effects, but a 300 mg

Coenzyme Q10 and Ubiquinol for Physical Performance
11
dosage of CoQ10 and a CoQ10 plasma level of 3.29 mg/l significantly increased
endurance and exhaustion improved in a maximum speed test on the
ergometer [16].
Figure 2. CoQ10 plasma levels in 10 Triathletes before and after supplementation with
180 mg CoQ10 for 4 weeks in mg/l.
Figure 3. Correlation of the plasma CoQ10 level changes with the change on physical
performance (sec) in 10 German professional triathletes.

Stefan Siebrecht, Darren Yak Leong Chan, Franklin Rosenfeld et al.
12
Today, we must conclude that the CoQ10 dosages used in the earlier
athlete studies were generally too low to achieve any significant positive
results. Clinical studies with athletes are increasingly showing positive effects
for a dosage of 300 mg CoQ10 or CoQ10 plasma levels >3.3 mg/l (Table 3).
With a dosage of QH even higher CoQ10 plasma levels can be achieved with
smaller dosages.
From previous studies we also know that athletes react extremely
differently to supplementation with CoQ10. In a double blind, placebo
controlled, crossover study, Geiß gave 180 mg of CoQ10 per day for 10 days to
10 triathletes, measured plasma CoQ10 levels and measured physical
performance as time to fatigue in a treadmill running test [12].
The major outcomes from the study from Geiß (1994) [12] were:
1. The tested triathletes had on average a lower CoQ10 plasma levels
than normal people. The average plasma CoQ10 level in the beginning
was 0.63 mg/l which fell to 0.58 mg/l after the placebo phase.
Average CoQ10 plasma levels in healthy people are normally higher
(around 0.83 to 1.0 mg/l): meaning that prolonged extreme endurance
exercise can lead to reduced CoQ10 plasma levels.Among these
athletes the vegetarian and vegan triathletes had the lowest CoQ10
plasma levels of all (around 0.4 mg/l which were 33% lower than the
average of all triathletes and more than 50% below normal values:
This means that a vegetarian and a vegan diet further decreases
plasma CoQ10 levels over and above prolonged extreme endurance
exercise
2. All 10 athletes reacted with very different increases in CoQ10 plasma
levels (Figure 2). Some athletes responded very well to CoQ10
supplementation and achieved plasma levels of above 2.5 mg/l with
the dosage of 180 mg of traditional CoQ10. Other triathletes that were
not included in the study had increases of CoQ10 levels up to 3.42
mg/l and also showed increases in physical performance. Some of the
triathletes were non-responders because their plasma CoQ10 levels did
not increase and or stayed almost at their starting values of around 0.6
- 1.0 mg/l although they had taken the same dosage of CoQ10. This
means: From the given dosage of CoQ10 and QH it is almost
impossible to predict the plasma CoQ10 level. Thus CoQ10 levels
should always be measured to identify the responders that are
characterized by greatly increased CoQ10 plasma levels after CoQ10 or

Coenzyme Q10 and Ubiquinol for Physical Performance
13
QH supplementation and the non-responders who react with low
CoQ10 plasma level increases.
3. The best effects on performance enhancement were found the people
with the highest CoQ10 plasma levels and who achieved the highest
increase in CoQ10 plasma levels.A positive correlation of plasma
CoQ10 levels with physical performance was found (Figure 3).
These data suggest that there is a threshold increase in CoQ10 plasma level
that must be reached to enhance performance. In the treatment of heart failure
a similar threshold was found which is at least above 2.5 mg/l or maybe even
higher (above 3.5mg/l) [26]. With QH supplementation plasma levels of
around 6 - 8 mg/l can be reached.
Studies measuring CoQ10 plasma levels and performance after CoQ10
supplementation in athletes and healthy people:
*Bioavailability enhanced CoQ10 formula
**found quite low CoQ10 plasma levels. Hosoe 2007 reached much higher CoQ10
plasma levels with the same ubiquinol dosage. Explanation is missing.
MEASURING PHYSICAL PERFORMANCE
Measuring human physical performance is difficult. To measure an
increase in performance, it is important to establish reliable measurement
parameters and also the test the configuration and range of test groups.
Performance can be measured in 5 different levels:
1. Increased performance in animals (rats)
2. Increase in true performance parameters in untrained individuals or
older athletes
Author Dosage and Form of CoQ10 Plasma level Effects
Zuliani 198929 100 mg traditional CoQ10 1.34 mg/l No effects
Amadio 199131 100 mg traditional CoQ10 1.85 mg/l Some performance enhancement
Geiß 200412 180 mg traditional CoQ10 1.63 mg/l Performance enhancement at levels >2.5mg/l
Zeppili 199130 100 mg traditional CoQ10* 2.23 mg/l Some Performance enhancement
Mizuno 200816 100 mg traditional CoQ10 1.94 mg/l No effects
Mizuno 200816 300 mg traditional CoQ10 3.29 mg/l Performance enhancement
Kon 200817 300 mg Ubiquinol (QH) 3.29 mg/l Performance enhancement
Hosoe 200715 300 mg Ubiquinol (QH) 6.80 mg/l Not Measured
Bloomer 201219 300 mg of Ubiquinol (QH)** 2.13 mg/l Some performance enhancement
Alf 201318 300 mg of Ubiquinol (QH) Not measured Performance enhancement

Stefan Siebrecht, Darren Yak Leong Chan, Franklin Rosenfeld et al.
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3. Increased endurance (time to exhaustion) and reduced clinical
parameters
4. Enhanced performance and recovery with intermittent exertion for
athletes
5. Enhanced true performance parameters for trained athletes
Level 1. The first indications of whether a substance can have
performance enhancing effect are usually obtained in animals (usually rats).
Level 2. The enhanced performance in untrained or older people is a low
level indication of a substance's potential to improve physical performance.
But training can have a confounding influence here and the effect of the
substance must be clearly differentiated from the effect of training.
Level 3. Endurance (time to exhaustion) is easy to measure and can
provide high values (10-30%) of performance Improvement. On the other
hand, time to exhaustion is not a true performance parameter and values are
generally higher than true performance enhancements usually by a factor of
around 10 times. Time to exhaustion does give a general indication of a
substance's potential to enhance performance.
Level 4. Enhanced performance for intermittent exertion is a true
parameter of enhanced performance, which is based on protecting the muscles
and improving recovery after exercise.
Level 5. The most difficult measurement to make but the most important
is to measure enhanced performance in trained athletes as changes are in the
order of only 1-3% (Alf 201318). If a substance has shown positive effects in
the lower test stages, this is a good indication that enhanced performance
might also be found in trained athletes. But if a substance does not show any
effects in the initial test levels, it can be concluded that this substance would
not be effective in trained athletes.
CoQ10 supplements have been shown to increase physical performance
parameters in a few studies:
• Level 1: In animals (rats) [32, 33]
• Level 2: In untrained athletes or older people [30, 34, 35]
• Level 3: In endurance athletes as time to exhaustion [16, 23, 36]
• Level 4: Enhanced performance in athletes for intermittent exertion
[18]
But CoQ10 can act, above all, as an indirect tool to enhance performance.
As CoQ10 reduces damage to cell membranes induced by exertion, recovery

Coenzyme Q10 and Ubiquinol for Physical Performance
15
time is shorter and higher exertion/performance can be achieved during further
exertion.
Physical Performance with Ubiquinol and Ubiquinone
Supplementation
As CoQ10 and QH are located in the mitochondria it would be expected
that the benefits would be stronger on the aerobic type 1 (slow twitch) muscles
that have a high content of mitochondria and are responsible for endurance
performance rather than in anaerobic type 2 (fast twitch) muscles that are
involved in sprinting and weightlifting. However, so far studies especially
using high dosages of QH supplementation have shown benefits in maximum
power output, maximum workload or maximum velocity, which is probably
mostly due to type-2 muscles that have far fewer mitochondria, and therefore
should be less dependent on CoQ10 because the muscles produce energy via
anaerobic metabolism [10, 18, 19, 35]. Thus it is a surprise that CoQ10
supplementation shows benefits more in the Type-II muscle performance than
in the aerobic Type-I muscle performance. The mechanism for the effects of
CoQ10 on Type II muscles is still unknown and speculative.
On the other hand if CoQ10 should work in the aerobic type 1 muscle it is
obvious that the concentration of CoQ10 within the mitochondria should be
higher so as to cause an increased and prolonged production of ATP preferably
from fatty acids via the ß-oxidation which could then lead to an enhancement
of aerobic endurance performance. In one study, muscular exhaustion was
reached at significantly higher workloads after CoQ10 treatment of 28 male
cyclists with 100 mg CoQ10 for 8 weeks. There was a statistically significant
difference of +4% between the, CoQ10 treatment and the placebo group (These
results could not be explained by a placebo effect, because in the placebo
group, there was no difference in maximal workload before and after treatment
[10]. These data are also confirmed by other studies [30, 34, 37].
Potential Mechanisms of Action for Ubiquinol and Ubiquinone
in Athletes
There are several potential mechanisms as to how ubiquinol and
ubiquinone could work in athletes to improve physical performance.

Stefan Siebrecht, Darren Yak Leong Chan, Franklin Rosenfeld et al.
16
Increase of Creatine Phosphate Production
The administration of 100 mg of CoQ10 over a period of six months
significantly increased creatine phosphate production after exercise in post-
polio patients [38]. Whether this could be a potential mechanism in healthy
athletes is not yet known.
Increasing Muscle Content of CoQ10
CoQ10 and QH work in the mitochondria of muscles.Type-1 muscle fibers
work mainly aerobically and therefore have many mitochondria in their cells.
In mitochondria, CoQ10/QH contributes to the electron transport of the
respiratory chain, which facilitates the production of ATP in muscle. Now the
question arises, can an increase of the CoQ10/QH content in the type 1 muscle
fibers increase the ATP production in the muscle, and thus lead to an increase
in the physical performance of the muscle. This would be the case if
CoQ10/QH production were involved at the rate limiting step of the respiratory
chain for ATP production. The question is whether it is possible to increase the
CoQ10 levels in the muscles through oral supplementation with CoQ10 and if
the CoQ10 that reaches the muscle is in fact really entering the mitochondrial
membrane and if this results in activation and an increase in the mitochondrial
metabolism and consequently ATP production. The uptake of CoQ10 into the
mitochondrial membrane is very strictly regulated and some scientists have
doubts that the mitochondrial CoQ10 can be increased by supplementation in
humans.
However, in animal models it was shown that chronic ingestion of
relatively large doses of CoQ10 in the diet was able to increase the CoQ10
concentrations especially in the mitochondrial fractions of heart and brain in
rodent models. This indicates that the dosage and the duration of oral CoQ10
administration are important key factors that influence the uptake by the
mitochondria in heart and the brain and possibly also muscle and other tissue
mitochondria [69, 70].
Lenaz has already claimed in 1987 that CoQ10 saturation of the
mitochondria is not reached under normal conditions and that slight changes in
the mitochondrial Q10/QH content cause greater changes in mitochondrial
energy production [39] (Figure 4). This would indicate that there is still a
capacity for the mitochondria to absorb more CoQ10 and to therefore increase
its metabolism.

Coenzyme Q10 and Ubiquinol for Physical Performance
17
Figure 4. Mitochondrial energy production as function of their CoQ10/ubiquinol
content (schematic) (Lenaz 1991).
Kon showed that the CoQ10 content increased in the aerobic working
type 1 (slow-twitch) muscles in rats after oral administration with CoQ10 [40].
Another effect was the reduction of the exercise-induced increase of the
muscle enzyme creatine kinase (CK) in the plasma thus CoQ10 promotes better
function and protection of cell membranes, and also causes a reduction in
stress-induced muscle damage. This study showed that the CoQ10 levels in the
type 1 (slow twitch) muscles can be increased by CoQ10 supplementation at
least in animal models. Similar evidence that the CoQ10 content in healthy
young human muscles can be increased by CoQ10 or QH supplementation is
still missing. However, in humans Rosenfeldt et al. showed that the CoQ10
content in the heart muscle of cardiac surgery patients could be elevated by
CoQ10 supplementation and that this resulted in increased efficiency of ATP
production [41]. Whether a similar effect in the muscles of healthy athletes
occurs has not yet been shown.
One study in humans a dosage of 120 mg CoQ10 given to athletes for 20
days was unable to increase the muscle CoQ10 content [42]. To increase the
human muscle CoQ10 content it seems to be necessary to maintain the plasma
CoQ10 levels as high as possible over a longer period of time, so that the

Stefan Siebrecht, Darren Yak Leong Chan, Franklin Rosenfeld et al.
18
muscle tissues have sufficient time to absorb the CoQ10 from the plasma.
Higher dosages of 200 - 300 mg CoQ10 per a day or preferably the better
bioavailable QH should be taken for a longer period of at least 4-12 weeks or
maybe even longer to increase muscle CoQ10 content. Whether it is possible to
increase the muscular CoQ10 content significantly by such CoQ10 or QH
supplementation and if this has any impact on physical performance is not yet
known and must be established by clinical trials.
In athletes, Cooke showed in 2008 that after 14 days of administration of
200 mg CoQ10 levels in muscle tended to increase. On the other hand an acute
CoQ10 dose increased muscular CoQ10 from 1.2µg/mg to 1.6µg/mg where the
placebo group showed a decrease in the muscular CoQ10 content, from
1.6µg/mg to 1.5µg/mg [23]. This could mean that acute exercise triggers the
uptake of CoQ10 into the muscle maybe due to an increased uptake of fats and
lipoproteins that also transport CoQ10. After exercise the muscular CoQ10 level
decreased again.
This could be an argument for a supplementation of QH and CoQ10 to
raise the QH plasma level as high as possible before the exercise to enable the
body to absorb more QH into the muscle. To raise the total muscle CoQ10
content it seems that doses of CoQ10 higher than 200 mg per day or for a
longer period than 14 days are necessary.
Changing of Muscle Composition
Clinical trials have shown an effect of CoQ10 administration on skeletal
muscles (vastus lateralis part of quadriceps) of aged individuals [43]. After
supplementation of 300mg CoQ10 per day for four weeks prior to hip
replacement surgery, muscle samples were analysed for changes in gene and
protein expression and muscle fiber type composition. In the CoQ10-treated
subjects, 47 genes were up-regulated and 68 down-regulated in comparison
with placebo-treated subjects. The expression of 174 proteins was induced by
CoQ10 while 77 proteins were repressed by CoQ10 supplementation. Muscle
fibers types were also affected by CoQ10 treatment; CoQ10-treated individual
showed a lower proportion of type I (slow twitch) fibers and a higher
proportion of type IIb (fast twitch) fibers, compared to age-matched placebo-
treated subjects [43]. Type II fast twitch muscles are important for strength
development. Elderly people especially lose Type II muscles during aging, and
hence could profit from CoQ10 supplementation.

Coenzyme Q10 and Ubiquinol for Physical Performance
19
Such an effect of CoQ10 and QH would also be interesting for strength
development in athletes such as weight lifters to accelerate muscle remodelling
towards a greater increase in muscle strength. It seems that CoQ10 and QH
stimulate the creation of fast twitch Type-2 muscle fibers which are needed for
fast developing muscle force and muscle strength. That would at least explain
why CoQ10 and QH supplementation has been shown to be effective in
disciplines such as maximum power output and strength (Type-2 muscle fiber
action) and not in endurance performance (Type-1 muscle fiber action).
Changing of Gene Expression by Ubiquinone and Ubiquinol
Supplementation
CoQ10 and QH supplementation have been shown to change the
expression of some genes that could be of great importance for athletes:
Up-Regulation
• Glutamate receptor protein GluR5, which has a function in neuronal
transmission and synapse development [44]
• Guanylyl cyclase, which is the receptor for nitric oxide signalling [45]
and which is redox sensitive [46]
• Fibroblast growth factor receptor N-SAM is essential for muscle
growth and development
• Activation of Lipolysis
• A number of protein kinases that are involved in cell cycle control and
cell signalling
Down-regulation
• TTF-1 interacting peptide 20, which is important in transcription
termination
• TR3 orphan receptor, which is a steroid hormone receptor involved in
apoptosis(Uemura 199847, Li 200048)
• Gene regulator hZFH helicase [49] is the major group Rhinovirus
receptor, which is an adhesion molecule essential for cold virus
infection [50]

Stefan Siebrecht, Darren Yak Leong Chan, Franklin Rosenfeld et al.
20
Other Potential Positive Effects of CoQ10 and Ubiquinol
Supplementation for Athletes
Stabilizing Red Blood Cells
CoQ10 is also important in the red blood cell membranes. CoQ10
supplementation can increase the CoQ10 content in red blood cells and make
the membrane more flexible and more resistant to oxidative stress [51].
This is important for athletes because the red blood cells are important for
the oxygen transport and a functioning membrane is needed for optimal
transfer of oxygen.
Increasing Blood Flow to the Working Muscles
It is known that CoQ10 supplementation improves endothelial function and
increases blood flow [8].
If similar mechanisms occur in athletes during exercise then an increased
blood flow to the working muscle would be beneficial to support aerobic
metabolism, to decrease formation of reactive oxygen radicals, decrease
formation of lactate and could reduce exercise-induced muscle damage.
Increasing Immune Function
CoQ10 has shown in animals and cells in vitro to enhance the activity of
immune cells and the cellular response to vaccines. An increased immune
function would be beneficial for athletes to reduce “open window” upper
respiratory tract infections) of athletes that often happen after strenuous
exercise
Antioxidant Action
High level physical activity increases production of oxygen free radicals
especially in untrained individuals [52]. High levels of oxygen free radicals
can impair cellular function [53]. Thus by building up antioxidant levels
CoQ10 could decrease the exercise-induced oxidative stress and thus improve
performance.

Coenzyme Q10 and Ubiquinol for Physical Performance
21
UBIQUINOL AND UBIQUINONE DOSAGES FOR ATHLETES
In studies to date similar dosages have been used in athletes as in non-
athletes. QH and CoQ10 are metabolically active ingredients that work
especially in the muscles and other tissues but little is known yet about the
actual need and demand for ubiquinol and ubiquinone in highly trained
intensive performing athletes. The same dosage of QH taken orally by athletes
with different bodyweights, leads to a different uptakes of QH per kg body
weight. So the CoQ10/QH dosage should be adapted to the body weight or the
weight of the muscles in the subject.
Table 1. Ubiquinol/Q10 dosage of 100 mg as function of bodyweight
Dosages of 300 mg QH have shown to enhance physical performance in
German Olympic athletes [18]. These athletes were lean with a body weight
between 70-80 kg and they took 300 mg QH per day, which is around 4 mg
per kg body weight. The same dosage consumed by a heavy strength athlete of
150 kg body weight would result in a dosage of only 2 mg per kg body weight
(see Table 1).
To achieve a constant and comparable QH dosage in all athletes with
different bodyweights of for example 4 mg QH per kg bodyweight a heavy
strength athlete with a weight of 150 kg would have to take 600 mg of QH. In
the future we expect that the optimal dosage for CoQ10 and QH
supplementation in athletes should be around the area of 4 - 6 mg CoQ10 or
QH per kg bodyweight which means that the supplemented QH dosages
should be adjusted by body weight (see Table 2).

Stefan Siebrecht, Darren Yak Leong Chan, Franklin Rosenfeld et al.
22
Table 2. Different ubiquinol/Q10 dosages as function of bodyweight
CONCLUSION
Overall we conclude that for athletes the CoQ10 dosages used in earlier
studies were simply too low to achieve consistently positive results. Clinical
studies on athletes show increasingly positive effects at a dosage of 300 mg of
CoQ10 and QH. It seems that there is a correlation between the CoQ10 plasma
levels > 3.3 mg/l and physical performance.
By QH, adequate plasma levels can be achieved with lower dosages than
with the CoQ10. In contrast, by using higher dosages of QH much higher
plasma CoQ10 levels can be achieved that are relevant for athletes in several
ways: to increase the muscular CoQ10 content and to induce performance
enhancing effects. Performance enhancing effects a have been shown after
supplementation of higher dosages of CoQ10 and or QH of 300 mg per day
over 4-6 weeks.
In the future the individual CoQ10 plasma levels should be measured and
individual dosages of 4-6 mg CoQ10/QH per kg bodyweight should be used by
athletes to achieve CoQ10 plasma levels higher than 2.5 mg/l (better higher
than 3.3 mg/l) for optimal performance.

Table 3. Studies of CoQ10 and ubiquinol (QH) supplementation in physical exercise
Author
Year
Year
Subjects
Q10/Ubiquinol
(QH) Dosage
Protocol
Performance
Benefits
Summary
1.
Alf et al.
(2012) [18]
2012
100 male and female
young top trained,
German Olympic
athletes, Double blind
placebo controlled
study
300 mg QH / day
6 weeks
Cycling to maximum
power output till they
reached the 4 mmol
lactate threshold
Yes
Maximum Power Output
(+2,5%)
(+11% QH Group vs +8,5%
Placebo)
2.
Amadio et
al. (1991)
[31]
1991
10 Male professional
basketball players (5
Verum, 5 control)
100 mg Q10 /
day
40 days
Astrand-Rhyming
test used for the
indirect calculation
of the V02max
Yes
VO2 max (+18%)
Plasma Q10 (0,85 to 1,85 mg/l) 
Cardiac performance parameters
3.
Bloomer et
al (2012)
[19]
2012
15 trained man and
women
(10 men and 5 women;
30–65 years
300 mg QH / day
4 weeks
Graded exercise
treadmill test and a
repeated cycle sprint
test were performed
(separated by 48
hours)
Trend
Trend to increased maximum
work load (P=0,06009), moderate
to strong correlation with higher
Q10 Plasma levels
4.
Bonetti et
al. (2000)
[10]
2000
28 Male cyclists,
single blind, placebo
controlled
100 mg Q10 /
day
8 weeks
Cycling
Incremental test with
increase of 50
W/minutes until
exhaustion
Yes, in some
parameters
Plasma Q10 levels
Aerobic power
Maximum Workload (+4%,
significant)
Improved tolerance of higher
workloads

Table 3. (Continued)
Author
Year
Year
Subjects
Q10/Ubiquinol
(QH) Dosage
Protocol
Performance
Benefits
Summary
5.
Braun et al.
(1991)54
1991*
10 male
cyclists
Parallel group
design
100 mg Q10 / day
8 weeks
Cycling
Incremental test to exhaustion
No
Oxygen Consumption (+4%,
NS)
Performance increased equally
in both groups from pre- to
post-supplementation. Q10 had
no effect on cycling
performance or any measured
parameters. Malondialdehyde
concentrations reduced in both
groups after training.
6.
Cerioli et
al.
(1991)55
1991
13 Male young
healthy
untrained
100 mg Q10 / day
30 days
Ergometer bicycle test for 60
min at 50% VO2Max and
followed by increases of 25
watts every 2 minutes till
exhaustion
Yes
Blood free fatty acid
concentration
Fat metabolism (Conclusion)
Aerobic exercise capacity
(Concl.)
7.
Cooke et
al.
(2008)23
2008
22 trained and
untrained
athletes
200 mg Q10 / day
14 days
Isokinetic knee extension
endurance test, a 30-second
Wingate anaerobic capacity
test, and a maximal
cardiopulmonary graded
exercise test interspersed with
30-minutes of recovery
Yes (Trend)
Muscle CoQ10 concentration
Serum SOD oxidative stress
Plasma CoQ10 concentrations
Time to exhaustion
(tendency)

Author
Year
Year
Subjects
Q10/Ubiquinol
(QH) Dosage
Protocol
Performance
Benefits
Summary
8.
Fiorella et
al. (1991)
[36]
1991
11 Highly
trained runners
100 mg Q10 / day
40 days
Running test
Yes
Longer distance (+12,9%)
Time to exhaustion (+7,9%) 
Exercise capacity (+13%)
9.
Geiß et al.
(2004) [12]
1994
10 trained
endurance
athletes
Placebo
controlled
double blind
study
180 mg Q10 / per
day
4 weeks
30 min cycling (submaximal)
50 levels increasing power to
maximum power output
Yes
Increase in Blood Q10 
10.
Gökbel et
al. (2010)
[35]
2010
15 healthy
sedentary men
100 mg Q10 / day
8 weeks
Five Wingate tests with
75g/kg body weight load with
2-minute intervals between
tests
3 times at baseline, after Q10,
or placebo supplementation
Yes
Mean Power output 
Fatigue index
11.
Guerra et
al. (1987)
[56]
1987
Professional
Cyclists
Cyclists had decreased plasma
levels of Q10 after several
races and at the end of the
cycling season
12.
Kaikkonen
et al.
(1998) [57]
1998
37 moderately
trained
marathon
runners
90 mg Q10 / day /
3 weeks
(+13.5 mg Vit E)
Marathon run
Not measured
No Change in Plasma Q10
Levels!!!
No Change in Plasma of any
other parameter!

Table 3. (Continued)
Author
Year
Year
Subjects
Q10/Ubiquinol
(QH) Dosage
Protocol
Performance
Benefits
Summary
13.
Kon et al.
(2008) [17]
2008
18 Male
professional
Kendo athletes
300 mg Q10 / day
20 days
Practicing Kendo for 5,5
h per d for 6 d
Yes
Plasma Creatin Phosphinase release

Plasma Myoglobin Release 
CoQ10 may prevent muscle damage
during sustained exercise.
14.
Laaksonen
et al.
(1995) [58]
1995*
11 young and 8
older trained
males
Crossover
design
120 mg Q10 / day
6 weeks
Cycling
Prolonged endurance test
to exhaustion
No—in fact,
performance
impairment
No change in muscle coenzyme Q10
concentrations or plasma
malondialdehyde as a result of
coenzyme Q10 supplementation.
Negative effect on time to
exhaustion (placebo had greater
endurance, -6%).
15.
Leelarungr
ayub
(2010) [59]
2010
16 young
swimmers
(7 males and 9
females,
15.13±0.96
years)
300 mg Q10 / day
12 days
Exhaustive exercise time
was evaluated before
(days 1 and 9) and after-
supplementation (day 22)
on a mechanical treadmill
using a modified Bruce
protocol. Swimming
speeds for 100 and 800
meters were recorded
Yes
Plasma CoQ10 (2.34±0.78 mg/l) 
Erythrocyte GSH increased
(p<0.05)
Maximal treadmill time (p<0.05) 
100m swimming time decreased
(p<0.05) 
800m swimming times (p>0.05). 

Author
Year
Year
Subjects
Q10/Ubiquinol (QH)
Dosage
Protocol
Performance
Benefits
Summary
16.
Malm et al.
(1996) [60]
1996*
15 active males
Parallel group
design
120 mg Q10 / day
20 days
Days 2–10: usual
activity
Days 11–15: 2/d
anaerobic training
Days 16–20: recovery
Cycling
Days 1, 11, 15 and
20
30-second Wingate
cycle + 5-minute
recovery + 10 × 10-
second sprints
No—in fact,
impairment
Placebo group improved
anaerobic work capacity at day 15
or 20—training effect. However,
Q10 group did achieve this
training effect. CK levels
maintained during placebo trial
but were increased at various time
points in Q10 group.
17.
Malm et al.
(1997) [61]
1997*
18 males
Parallel group
design
120 mg Q10 / day
22 days
Days 2–9: usual
activity
Days 11–14: 2/d
anaerobic training
Days 15–22: recovery
Cycling anaerobic
test (days 1, 11, 15
and 20)
30-second Wingate
cycle + 5-minute
recovery + 10 × 10-
second sprints
Aerobic test (pre-trial
and day 18)
Cycling VO2 max
Aerobic test (pre-trial
and day 22)
Running VO2 max
No—in fact,
impairment
No
No
Placebo and Q10 group both
improved performance of
repeated sprint test after training,
however, only placebo group
maintained this improvement
during recovery to day 20.
Placebo group achieved higher
average power, and greater
improvement in latter intervals
during anaerobic training
sessions. No change in VO2 max
outcomes in either group over
time or in oxygen use during
submaximal cycling.

Table 3. (Continued)
18.
Author
Year
Year
Subjects
Q10/Ubiquinol
(QH) Dosage
Protocol
Performance
Benefits
Summary
19.
Mizuno et
al. (2008)
[16]
2008
17 healthy
volunteers,
double-blinded,
placebo-
controlled, three
crossover
design
100mg Q10 / day
300mg Q10 / day
8 days
Workload trials on a bicycle
ergometer at fixed workloads
twice for 2 h and then rested
for 4 h. During the physical
tasks, subjects performed non-
workload trials with maximum
velocity for 10 s at 30 min (30-
rnin trial) after the start of
physical tasks and 30 min
before the end of the tasks
(210-rnin trial).
Yes
Maximum velocity 
Subjective fatigue sensation 
(both effects only in the 300 mg
group)
20.
Nielsen et
al. (1999)
[62]
1999*
7 well-trained
male triathletes
Crossover
design
100 mg Q10 /
day
6 weeks
(+ vitamin E +
vitamin C)
Cycling
Incremental VO2 max test to
exhaustion
No
No effect on maximal oxygen
uptake or muscle energy
metabolism (determined by
nuclear magnetic resonance
spectroscopy).
21.
Porter et al.
(1995) [63]
1995
15 middle-aged
men (44,7 y)
(44.7 + 2.0
years)
Placebo
controlled
150 mg Q10 /
day
2 months
Cycling Ergometer test
blood levels of CoQ10 
subjective perceived level of
vigor 
Lactate release (Tendency) 
Aerobic capacity 
firearm exercise metabolism 

Author
Year
Year
Subjects
Q10/Ubiquinol
(QH) Dosage
Protocol
Performance
Benefits
Summary
22.
Snider et
al. (1992)
[64]
1992*
11 highly
trained
triathletes
Crossover
design
100 mg Q10 /
day
4 weeks
+ vitamin E,
inosine,
Cytochrome C
Cycling and running
90 minutes on treadmill at 70%
VO2 max +
cycling at 70% VO2 max to
exhaustion
No
Time to exhaustion (+4%,
P=0,57)
No differences in blood
metabolites or RPE.
High dose Vitamin E blocks
absorption of Q10!
23.
Vanfraeche
m et al.
(1981) [37]
1981
6 inactive young
men
60 mg Q10 / day
4 to 8 weeks
Maximal aerobic test on an
electromagnetic bicycle
ergometer (Löde)
Yes
Exercise performance 
24.
Weston et
al. (1997)
[65]
1997*
18 trained male
cyclists and
triathletes
Parallel group
design
1 mg/kg Q10 /
day
for 28 days
Cycling
Incremental test to exhaustion
No
Test undertaken pre- and post
28 days of training; coenzyme
Q10 did not enhance
performance compared with
placebo group.
25.
Wyss et al.
(1990) [11]
1990
18 healthy
young untrained
male athletes
double-blinded
placebo-
controlled
crossover study
100 mg Q10 /
day
30 days
strenuous exercise test with
increasing work load, tests to
measure vo2max of each
athlete
Yes
Total oxygen uptake after
maximum intensity exercise
(+9%) 
Oxygen equivalence of lactic
acid
Total oxygen metabolism 
Maximum oxygen uptake 
Maximum work capacity
(+33%) 
Total work volume 

Table 3. (Continued)
Author
Year
Year
Subjects
Q10/Ubiquinol
(QH) Dosage
Protocol
Performance
Benefits
Summary
26.
Yamabe et
al. (1991)
[34]
1991
Subjects with
decreased work
ability absent from
disease
Middle aged
housekeepers with
sedentary lives
90 mg Q10 / day
6 months
Treadmill exercise test. 1
min incremental Test
which was appropriate to
detect the anaerobic
threshold. Subjects
underwent the
symptomatic maximal load
Yes
Physical ability 
Exercise aerobic function
Increase in exercise time
Peak VO2 
Anaerobic threshold 
Severity of symptoms of
physical inability 
27.
Ylikoski et
al. (1997)
[66]
1997
25 Finnish top-level
cross-country skiers
double-blind cross-
over study
Parallel Group
design
90 mg Q10 / day
6 weeks
Cross-country skiing
Treadmill pole-walking to
exhaustion
Yes
VO2Max (+3%)
Exercise capacity (+5%)
Improved performance and
recovery time in 94% Q10
period vs 33% in placebo
period.
Improved VO2 max with
coenzyme Q10
supplementation. Increase in
aerobic and anaerobic
thresholds. No control of
exercise during
supplementation periods.

28.
Author
Year
Year
Subjects
Q10/Ubiquinol
(QH) Dosage
Protocol
Performance
Benefits
Summary
29.
Zeppili et
al. (1991)
[30]
1991
9 Volleyball
athletes and
inactive adults
100 mg Q10 / day
30 days
Maximal graded supine bicycle
exercise test (30 watt increase
every 4 min)
Yes
Total work capacity
(+10%)
Maximum oxygen uptake
(+11%)
Plasma Q10 concentration
30.
Zhou et al
(2005) [67]
2005
6 healthy
volunteers
Single blind
study
mg Q10 / day
4 x 2-week phases,
Placebo run-in
CoQ10 (150 mg/d)
CoQ10 (150 mg/d)
+ Vit E (1,000 IU)
Placebo wash-out
Three-stage cycle economy test (4
minutes at each of 50, 100, and
150 watts), followed by a
VO2max test (25 watts increment
every minute till exhaustion),
were performed prior to the
supplementation and at the end of
each phase. (Comment: High dose
Vitamin E blocks the absorption
of Q10!)
No,
Yes, in some
subjective
parameters
Plasma CoQ10 (P<0.05)
Muscle CoQ10
concentration
VO2max ventilatory
threshold
Exercise economy
Oxygen deficit
31.
Zuliani et
al. (1989)
[29]
1989
12 healthy
untrained
subjects
100 mg Q10 / day
28 days
Exhaustive cycling exercise test
Free Fatty Acid levels 
*Adapted from a table of chapter 16. Supplements and sports foods, Burke and Deakin (eds). Clinical Sports Nutrition, 4th ED, McGraw
Hill, Sydney 2010 (Version December 2011) [68].

Stefan Siebrecht, Darren Yak Leong Chan, Franklin Rosenfeld et al.
32
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LCH