Effects of a Commercial Herbal-Based
Formula on Exercise Performance in Cyclists
CONRAD P. EARNEST1, GINA M. MORSS1, FRANK WYATT2, ALEXANDER N. JORDAN1, SHEREE COLSON3,
TIMOTHY S. CHURCH1, YOLONDA FITZGERALD3, LANCE AUTREY3, RADIM JURCA1,
and ALEJANDRO LUCIA4
1The Cooper Institute Center for Human Performance and Nutrition Research, Dallas, TX;2Louisiana Tech University,
Ruston, LA;3Baylor University, Center for Exercise, Nutrition & Preventive Health Research, Waco, TX; and
4Department of Physiology, European University of Madrid, SPAIN
EARNEST, C. P., G. M. MORSS, F. WYATT, A. N. JORDAN, S. COLSON, T. S. CHURCH, Y. FITZGERALD, L. AUTREY, R.
JURCA, and A. LUCIA. Effects of a Commercial Herbal-Based Formula on Exercise Performance in Cyclists. Med. Sci. Sports Exerc.,
Vol. 36, No. 3, pp. 504–509, 2004. Introduction/Purpose: We examined the effects of a commercially marketed herbal-based formula
purported to increase endurance on oxygen consumption (V˙O2) in 17 competitive category III/IV amateur cyclists [mean (SEM) age:
31.1 (1.8) yr; height: 178.5 (1.8) cm; weight: 77.1 (1.6) kg]. Methods: Each cyclist participated in two (pre/post) cycling tests
progressing 25 W·4 min?1starting at 100 W administered in a randomized, placebo-controlled, double-blind fashion. The second trial
was performed 14 d after the ingestion of a manufacturer recommended loading phase (4 d ? 6 caps·d?1) and a maintenance phase
(11 d ? 3 caps·d?1). Three treatment capsules contained 1000 mg of Cordyceps sinensis (CS-4) and 300 mg Rhodiola rosea root extract
as the primary ingredients; 800 mg of other ingredients included calcium pyruvate, sodium phosphate, potassium phosphate, ribose,
and adenosine and 200 mcg of chromium. Results: Using a 2 ? 2 ANOVA, we observed no significant treatment effect for any between
or within group variables including peak V˙O2[treatment 4.14 (0.2) L·min?1; placebo 4.10 (0.2) L·min?1], time to exhaustion [treatment
38.47 (1.7) min; placebo 36.95 (1.8) min], peak power output (PO) [treatment 300.00 (12.1) W; placebo 290.63 (12.9) W], or peak heart
rate. We also observed no differences for any subpeak exercise variable including the PO eliciting 2 mmol·L?1blood lactate (BLa)
[treatment 201.00 (18.1) W; placebo 167.50 (19.2) W] and 4 mmol·L?1BLa [treatment 235.88 (15.8) W; placebo 244.78 (14.9) W],
ventilatory threshold, respiratory compensation point, or V˙O2L·min?1and gross efficiency at each stage. Conclusion: A 2-wk
ingestion schema of a commercial herbal-based formula is insufficient to elicit positive changes in cycling performance. Key Words:
HERB, SUPPLEMENT, NUTRITION, CYCLING
competition. Beyond these three basic categories, research
efforts have validated few legal dietary supplements that
will improve cycling performance. Two herbal supplements
traditionally used in Chinese and Ayurvedic (i.e., holistic)
medicine have been marketed to endurance athletes as a
means of increasing parameters associated with oxygen
uptake. These are Cordyceps sinensis and Rhodiola rosea.
In brief, Cordyceps sinensis has been a popular herbal
medicine in China for centuries (29,30). The active compo-
nent associated with Cordyceps is mycelium, which is ob-
n an effort to improve or maintain endurance perfor-
mance, cyclists traditionally use carbohydrates, water,
and electrolyte ingestion schemas during training and
tained from the parasitic fungus of a colonizing larvae of the
moth that inhabits the host’s body (29,30). To obtain the
active ingredient, the mycelium is derived from the mycelial
strain Paecilomyces hepiali to form CS-4. This latter com-
ponent has been shown to increase the cellular energy state
in mouse liver by 18% as assessed by31PNMR spectroscopy
(5). In addition, CS-4 significantly decreased oxygen con-
sumption (V˙O2) and mortality in mice exposed to a hypoxic
Rhodiola rosea is also a popular plant used in traditional
medical systems in Eastern Europe and Asia with a reputa-
tion for stimulating the nervous system, decreasing depres-
sion, enhancing work performance, eliminating fatigue, and
preventing high altitude sickness (3,29,30). Rhodiola has
been categorized as an adaptogen due to its reported ability
to increase resistance to a variety of chemical, biological,
and physical stressors via cardioprotection and central ner-
vous system enhancement (29,30). Some reports also claim
that Rhodiola attenuates various conditions such as a decline
in work performance, sleep difficulties, poor appetite, irri-
tability, headaches, and fatigue associated with intense
physical or intellectual strain (6,10,20,21). These “adapto-
genic,” cardiopulmonary protective, and central nervous
system activities have been attributed to Rhodiola’s ability
to influence the levels and activity of monoamines and
Address for correspondence: Conrad Earnest, Ph.D., FACSM, Director,
Center for Human Performance and Nutrition Research, The Cooper In-
stitute Centers for Integrated Health Research, 12330 Preston Road, Dallas,
TX 75230; E-mail: firstname.lastname@example.org.
Submitted for publication August 2003.
Accepted for publication November 2003.
MEDICINE & SCIENCE IN SPORTS & EXERCISE®
Copyright © 2004 by the American College of Sports Medicine
opioid peptides such as beta-endorphins (29,30). Interest-
ingly, one study using Rhodiola crenulata in professional
Chinese athletes did show an increase compared with con-
trols after 75 d of supplementation (18).
Enhancing public visibility and the marketability of these
supplements are reports that have accumulated over the last
10–12 yr suggesting that several Olympic teams have used
adaptogens to enhance exercise performance. These sports
include hockey, cross-country skiing, women’s soccer, cy-
cling, and track. Perhaps one of the most intriguing “testi-
monial” reports was when Cordyceps gained world attention
in 1993 following the success of Chinese female runners
who achieved records in 1500-m, 3000-m, and 10,000-m
events, while attributing their success to a diet containing
Cordyceps. Unfortunately, few if any references exist in the
more traditionally utilized Western literature substantiating
the benefits of Cordyceps or Rhodiola in endurance athletes.
In this current investigation, we examine the effects of a
commercially available multi-ingredient formula containing
as its primary ingredients Cordyceps sinensis and Rhodiola
rosea on oxygen uptake in competitive amateur cyclists.
We recruited 17 amateur male competitive cyclists for
this study. All cyclists were active in category III/IV racing
events. We tested nine cyclists at The Cooper Institute
Center for Human Performance and Nutrition Research in
Dallas, TX. We tested eight cyclists at the Baylor University
Cycling Research Center in Waco, TX, and examined all
cyclists using the same protocol and same equipment at each
laboratory (see below). All of the subjects in this investiga-
tion had previously undertaken maximal exercise testing in
the aforementioned centers and were familiar with maximal
exercise testing procedures. The research ethics committee
from each university approved the study and before under-
taking the testing of this investigation, all subjects signed a
written informed consent statement outlining the potential
risks associated with the trial.
Exercise testing procedures. All subjects reported
to each laboratory for exercise testing on two separate days.
All cyclists performed their first test on day 0 (baseline)
without supplementation. We examined all cyclists a second
time after a 14-d supplementation period. We chose this
length of supplementation based on the product manufac-
turer’s recommendation. During the supplementation pe-
riod, each subject ingested an adaptogen formula (treatment;
detailed below) or a matched placebo. Each testing period
entailed having the subject perform a staged cycling test to
exhaustion. We adjusted the ergometer before each test to
duplicate the measurements of each cyclist’s personal
Exercise test. We performed each test on a Lode Ex-
calibur Sport Ergometer (Groningen, The Netherlands) and
analyzed the riders for cardiorespiratory parameters using a
Parvomedics Truemax Metabolic System (Salt Lake City,
UT). We instructed each subject to prepare for each test as
if preparing for a race. This preparation included not chang-
ing their training parameters or dietary patterns for the week
preceding each test. On the day before each test, subjects
followed a similar type of high-carbohydrate (CHO) diet
(CHO intake of ?450–500 g·d?1). Two to three hours
before the test, subjects ate a light snack. We also asked
each subject to abstain from ingesting any drugs that would
influence heart rate (HR) on the day of each test. The one
exception was caffeine, which we asked the subjects to
refrain from consuming for at least 5 h before testing.
Each cycling test began with a warm-up at 50 W (10 min)
and then progressed to 75 W (2 min). After this warm-up,
the test began by increasing the power output (PO) to 100
W. Once PO was set at 100 W, each stage inclusive of the
100-W stage lasted 4 min and progressed 25 W every 4 min
until the rider reached exhaustion or could no longer main-
tain a pedal cadence of 50 rpm. During the test, subjects
adopted a conventional (upright) cycling posture during the
duration of the tests. This posture was characterized by a
trunk inclination of ? 75% and by the cyclists placing their
hands on the handlebars with elbows slightly bent (flexion
? 10%). We allowed each rider to choose their preferred
cadence within the range of 70–90 rpm. Though we desired
to have each rider perform a maximal exercise test, per se,
we do not consider this a true V˙O2maxtest, which would
optimally be shorter. Instead, we applied a slow rate of PO
increase in this study in an effort to delineate where poten-
tial treatment effects might lie [i.e., (i) submaximal efforts,
(ii) efforts surrounding various thresholds (outlined below),
or (iii) efforts near peak performance]. Thus, we will refer
to all “maximal” data as peak data.
Measurements during the tests. We collected gas
exchange data continuously using an automated computer-
ized breath-by-breath Parvomedics Truemax Metabolic Sys-
tem using a pneumotachometer and a paramagnetic O2
analyzer and infrared CO2analyzer to perform O2and CO2
analyses, respectively. This system has been shown to be
accurate as compared with Douglas bag criteria (1). In
addition, each center used the same calibration procedures
for each metabolic cart inclusive of a 3-L calibration sy-
ringe, and calibration gases of similar concentration (16%
O2, 4% CO2, and balanced nitrogen) that were obtained
from the manufacturer of the metabolic cart. We averaged
all gas exchange data in 60-s intervals, and only the last
minute of each stage was used in our analyses. The follow-
ing variables were measured during each test: V˙O2, pulmo-
nary ventilation (V˙E), ventilatory equivalents for oxygen
tidal partial pressure of oxygen (PETO2) and carbon dioxide
(PETCO2). We subsequently used these parameters to ex-
amine the PO where ventilatory threshold (VT) and respi-
ratory compensation point (RCP) occurred. The VT was
determined using the criteria of an increase in both V˙E·V˙O2
and PETO2with no concomitant increase in V˙E·V˙CO2
whereas the RCP was determined using the criteria of an
increase in both the V˙E·V˙O2
crease in PETCO2(15). V˙O2peakand peak power output (PO;
W) was chosen as the peak values observed during the last
full min completed during the cycling tests. Blood samples
?1) and carbon dioxide (V˙E·V˙CO2
?1), and end-
?1and V˙E·V˙CO2and a de-
CYCLING AND HERBAL SUPPLEMENTATIONMedicine & Science in Sports & Exercise?
(25 ?L) for the measurement of blood lactate (BLa; Analox
GM7 MicroStat Analyzer; London, UK) were taken from
fingertips at rest and during the last 30 s of each stage
starting at 100 W. V˙O2and PO at 2 mmol·L?1, and 4
mmol·L?1were determined from individual V˙O2-PO and
blood lactate-PO relationships. For those PO eliciting a
respiratory exchange ratio (RER) value ?1.00, we also
calculated gross efficiency (GE). GE is defined as the ratio
of work accomplished per minute [i.e., W converted to
kcal·min?1) compared with the energy expended per minute
[i.e., V˙O2(average for the last minute of each PO) converted
to kcal·min?1], using the corresponding energy equivalent
for each V˙O2value based on RER (4).
Supplementation. We used a commercially available
supplement known as OptygenTMfor this study (First En-
durance; Salt Lake City, UT; www.firstendurance.com). We
instructed riders to consume their respective treatments ac-
cording to manufacturer recommendations and ingest their
supplements in two phases: A loading phase (6 capsules·d?1
for 4 d) and a maintenance phase (3 capsules·d?1for 11 d).
We provided subjects with identical capsules for each treat-
ment condition. Each set of capsules (i.e., treatment and
placebo) was colored in a dark red, nontransparent capsule.
The placebo was comprised of methycellulose, an inert
substance with no significant caloric value or biologic ac-
tivity. Although each product had a distinctive odor, we
were unable to precisely match the smell of the active
treatment. Each three capsules contained a manufacturer
claimed combined quantity of 1000 mg of Cordyceps CS-4
(Cordyceps sinensis) (mycelia biomass) minimum 7%
cordycepic acid and 300 mg of Rhodiola extract (Rhodiola
rosea root) containing a minimum 2.5% salidrosidesmini-
mum and 3.0% rosavins as its primary ingredients. The
supplement also contained a “proprietary blend” of 800 mg
of combined calcium pyruvate, sodium phosphate, potas-
sium phosphate, ribose, and adenosine. However, as is
stated by DSHEA, “When the dietary ingredients in a sup-
plement are considered to be a proprietary blend, just the
total amount of the blend need be stated. In the absence of
individual amounts, FDA requires that the dietary ingredi-
ents in a proprietary blend are to be listed in order of
predominance by weight (www.cfsan.fda.gov/?dms/guid-
ance.html).” Therefore, we have no further information re-
garding the exact weight of each substance contained in the
matrix. This product also contains 200-mcg chromium (as
chelate). Lastly, even though we received from the manu-
facturer a certificate of analysis attesting to the veracity of
the product, we did not have the product independently
Statistics. We analyzed our data using a 2 ? 2 [treat-
ment (placebo/treatment) ? time (pre/post)] ANOVA. Our
primary analysis examined the relationship between treat-
ment and peak V˙O2, peak HR, and time to exhaustion for
each testing period. As a secondary analysis, we examined
the V˙O2and GE for the O2cost averaged over the final
minute of each stage below an RER of 1.0. During this latter
analysis, we also examined the PO corresponding to the
accumulation of 2 mmol·L?1and 4 mmol·L?1of BLa
during each trial condition, as well as the PO at VT and
RCP. If we observed a significant statistical result, we used
a Fischer’s least significant difference posthoc analysis to
examine statistical differences for each statistically signifi-
cant parameter. Results are shown as mean (SEM).
All 17 subjects successfully completed each testing pe-
riod, with nine subjects assigned to the treatment group and
eight subjects to the placebo group. The rider characteristics
for the treatment group were age: 31.6 (2.8) yr, weight: 76.6
(2.1) kg, and height: 176.0 (2.3) cm. The rider characteris-
tics for the placebo group were age: 30.5 (2.2) yr, weight:
77.7 (2.6) kg, and height: 181.3 (2.6) cm. We did not
observe any statistically significant difference between or
within treatment groups for any peak exercise variables
including peak V˙O2, time to exhaustion, peak W, or peak
HR (Table 1). Furthermore, we did not observe any statis-
tically significant difference between or within treatment
group differences for any of the subpeak exercise variables
including the PO eliciting 2 mmol·L?1and 4 mmol·L?1BLa
(Table 1), VT, RCP, or V˙O2(Fig. 1) or GE (Fig. 2) at any
The primary findings from our study is that a formula
based primarily on two herbs, Cordyceps sinensis and
Rhodiola rosea, and a matrix of other ingredients marketed
to enhance ATP production and endurance performance had
no effect on exercise performance. These findings included
TABLE 1. Data represent peak exercise and various threshold data for each
Time to exhaustion (min)
Peak PO (W)
Peak HR (beats?min?1)
PO at 2 mmol?L?1BLa
PO at 4 mmol?L?1BLa
PO at VT
PO at RCP
RER, respiratory exchange ratio; HR, heart rate; PO, power output (W); VT, ventilatory
threshold; RCP, respiratory compensation.
Official Journal of the American College of Sports Medicinehttp://www.acsm-msse.org
peak V˙O2, peak PO, and time to exhaustion. We also did not
observe any treatment effects on subpeak exercise perfor-
mance inclusive of various “threshold” parameters tradition-
ally examined in the study of exercise physiology. There-
fore, it appears that this commercial product confers no
ergogenic effect when ingested over a 14-d treatment pe-
riod. Whether this formula will prove to have a benefit to
exercise when ingested over longer periods has yet to be
The comparison of our data to previous studies is diffi-
cult, as most references to the effects of the herbs contained
in this formula appear in non-English journals (i.e., Chinese
and Russian), as conference abstracts (5,27,28), or as review
articles that cite many non-English reports (3,10,29). Thus,
one must presume that the authors of these reviews have
read and correctly interpreted the information presented.
Though we do not doubt the validity of these reports, per se,
it is difficult to make thorough comparisons.
The effect of Cordyceps sinensis has been reviewed thor-
oughly elsewhere as to its effects on various physiological
functions (29,30). Given the breadth of these reports, it is
likely that a “physiologic effect” does exist via Cordyceps
use. However, Cordyceps’ role in enhancing exercise per-
formance is unclear. As with many dietary supplements, the
efficacy of Cordyceps is largely anecdotal and heavily le-
veraged on media reports attesting to the purported use by
successful Chinese athletes. Currently, we are aware of only
two conference abstracts attesting to the role of Cordyceps
in energy metabolism. The first was performed in mice,
where it was shown that the administration of Cordyceps
showed an increase in31PNMR spectroscopy hepatic ATP
(5). Though no evidence was provided in this report regard-
ing the effects of Cordyceps in muscle tissue, should these
effects be noted in muscle, an increase in exercise perfor-
mance might be possible. To this end, Xaio et al. (28) have
presented conference data in elderly humans showing an
increase in pre/post V˙O2max [mean (SEM); 1.9 (0.1)
L·min?1vs 2.0 L·min?1(0.1)] (28). These effects were
noted at peak exercise, as well as during anaerobic threshold
as determined by the visual plotting of V˙CO2vs V˙O2and
V˙EQO2vs time [1.15 (0.1) L·min?1vs 1.3 L·min?1(0.1)].
Though statistically significant, the calculation of statistical
power surrounding these data reveals values of 0.10 and
0.20 for each respective comparison. Another distinguishing
feature is that this particular study used a 6-wk ingestion
schema, which may be necessary to observe a treatment
effect if one does indeed exist.
The reported data regarding Rhodiola rosea is equally
difficult for comparison purposes. In one full paper, a
Rhodiola rosea extract was administered to students for 20 d
during a stressful examination period (21). The most sig-
nificant improvement in the Rhodiola group was a reported
FIGURE 1—Data (mean ? SEM) represent the oxygen consumption (V˙O2) during the last minute of each stage for each treatment group.
CYCLING AND HERBAL SUPPLEMENTATION Medicine & Science in Sports & Exercise?
improvement in physical fitness, mental fatigue, and neu-
romotoric tests. However, it is unclear how these measure-
ments were ascertained, though similar effects have been
reported by others (20). However, it does appear as though
Rhodiola does not increase oxyhemoglobin saturation, at
least with acute exposure, as a recent trial entailing 60 min
of acute hypoxic exposure (13.5% O2) and 7 d of Rhodiola
supplementation (447 mg·d?1) showed no benefit (27). In
fairness, we would like to caution the reader that our ob-
servation is also made from a conference report and that a
complete analysis of the study protocol is not possible. The
one report that we have found examining humans has shown
a modest increase in V˙O2maxin professional Chinese ath-
letes using Rhosea crenulta (18). However, this type of
Rhodiola is a different species, which likely confers differ-
ent chemical properties and biologic function.
This formula also contained chromium and an 800-mg
proprietary blend composed of calcium pyruvate, sodium
phosphate, potassium phosphate, D-ribose, and adenosine.
In short, all of these ingredients are promoted to enhance
energetics in humans. When applicable, even though some
of these ingredients have demonstrated an ergogenic effect
during exercise, the quantities contained in this formula are
not present in the quantities found to be effective in the
literature. For example, chromium has been promoted to
enhance insulin sensitivity and, subsequently, glucose and
fatty acid disposal (16,17,19). However, no ergogenic ben-
efit can be assigned to the use of chromium during exercise
performance (7). Further, even though some evidence sug-
gests that pyruvate may have an ergogenic benefit when
administered in large, gram quantities (i.e., ? 30 g·d?1) the
quantities present in this formula are dramatically lower
than these reports showing efficacy (22–24).
An interesting observation at this point is that DSHEA
does not require companies to reveal the actual concentra-
tion of an ingredient when presented in a proprietary blend.
Thus, it is safe to assume that the pyruvate present in this
product’s matrix is below the 800 mg listed on the label. In
addition to pyruvate, there is some data available to suggest
that sodium phosphate and potassium phosphate may im-
prove several indices of performance including maximal leg
power, oxygen consumption, and endurance performance
(8,12,13,26). For the same reasons cited above, the admin-
istration of phosphates in trials demonstrating efficacy is
larger (?4 g·d?1) than what is present in this formula. The
data are even less impressive for D-ribose, a carbohydrate
involved in purine nucleotide metabolism and serves as a
backbone for de novo ATP synthesis.
Supplementation with this molecule has been shown to
have some clinical efficacy in clinical populations with
AMP deaminase deficiency and myoadenylate deaminase
deficiency (9,25). However, two trials in healthy strength
FIGURE 2—Data (mean ? SEM) represent the gross efficiency (GE) for each treatment group during the last minute of each stage.
Official Journal of the American College of Sports Medicine http://www.acsm-msse.org
training athletes have shown no benefit from D-ribose sup- Download full-text
plementation and no data have been reported on its effects
on endurance performance (2,11).
Our study and its conclusions have several limitations.
First, we did not have the product independently analyzed.
Though we obtained a certificate of analysis with an
accompanying product identification number, we cannot
be certain that all of the ingredients listed were present.
Second, we cannot say to what amount those ingredients
in the “proprietary blend” are present as DSHEA does not
require companies to list these quantities, only the order
from which they are present in largest to smallest quan-
tities. Third, it is possible that we did not allow the
cyclists to ingest the product for a long enough period,
despite manufacturer recommendations. Despite these
limitations, we conclude that an herbal-based commercial
formula containing Cordyceps sinensis and Rhodiola
rosea as its primary ingredients and other matrix material
postulated to improve ATP production has no effect on
cycling performance when ingested for 14 d. Whether a
longer supplementation period will prove efficacious is
still a matter for scientific inquiry.
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