Tongkat Ali as a Potential Herbal Supplement for Physically Active Male and Female Seniors-A Pilot Study

Abstract

Tongkat Ali (Eurycoma longifolia; TA) is known to increase testosterone levels and alleviate aging males' symptoms. This study aimed at investigating TA as an ergogenic supplement for elderly people. Thirteen physically active male and 12 physically active female seniors (57-72 years) were supplemented with 400-mg TA extract daily for 5 weeks. Standard hematological parameters were taken. In addition, the concentrations of total and free testosterone, dihydroepiandrosterone, cortisol, insulin-like growth factor-1, and sex hormone-binding globulin were analyzed. As additional biochemical parameters, blood urea nitrogen and creatine kinase as parameters of kidney function and muscle damage, respectively, as well as the muscle strength by a simple handgrip test were determined. After treatment, hemoglobin, testosterone, and dihydroepiandrosterone concentrations, and the ratio of total testosterone/cortisol and muscle force remained significantly lower in female seniors than in male seniors. Hematocrit and erythrocyte count in male seniors increased slightly but were significantly higher than in female seniors. Treatment resulted in significant increases in total and free testosterone concentrations and muscular force in men and women. The increase in free testosterone in women is thought to be due to the significant decline in sex hormone-binding globulin concentrations. The study affirms the ergogenic benefit of TA through enhanced muscle strength. Copyright © 2013 John Wiley & Sons, Ltd.

Full text

Tongkat Ali as a Potential Herbal Supplement for
Physically Active Male and Female Seniors—A
Pilot Study
Ralf R. Henkel,
1
*
†
Ruxiang Wang,
2†
Susan H. Bassett,
3
Tao Chen,
4
Na Liu,
2
Ying Zhu
4
and
Mohd Ismail Tambi
5
1
Department of Medical Bioscience, University of the Western Cape, Bellville 7535, South Africa
2
Shenyang Center for Disease Control and Prevention, Shenyang, China
3
Department of Sport, Recreation and Exercise Science, University of the Western Cape, Bellville 7535, South Africa
4
Liaoning Sport Science Institute, Shenyang, China
5
Wellmen Clinic, Damai Service Hospital, Kuala Lumpur 52100, Malaysia
Tongkat Ali (Eurycoma longifolia; TA) is known to increase testosterone levels and alleviate aging males’
symptoms. This study aimed at investigating TA as an ergogenic supplement for elderly people. Thirteen
physically active male and 12 physically active female seniors (57–72 years) were supplemented with 400-mg TA
extract daily for 5 weeks. Standard hematological parameters were taken. In addition, the concentrations of total
and free testosterone, dihydroepiandrosterone, cortisol, insulin-like growth factor-1, and sex hormone-binding
globulin were analyzed. As additional biochemical parameters, blood urea nitrogen and creatine kinase as
parameters of kidney function and muscle damage, respectively, as well as the muscle strength by a simple
handgrip test were determined. After treatment, hemoglobin, testosterone, and dihydroepiandrosterone
concentrations, and the ratio of total testosterone/cortisol and muscle force remained significantly lower in female
seniors than in male seniors. Hematocrit and erythrocyte count in male seniors increased slightly but were
significantly higher than in female seniors. Treatment resulted in significant increases in total and free testosterone
concentrations and muscular force in men and women. The increase in free testosterone in women is thought to be
due to the significant decline in sex hormone-binding globulin concentrations. The study affirms the ergogenic
benefit of TA through enhanced muscle strength. Copyright © 2013 John Wiley & Sons, Ltd.
Keywords: Eurycoma longifolia; adaptogen; testosterone; ergogenic benefits; increased muscle strength; elderly individuals.
INTRODUCTION
Tongkat Ali (TA), Long Jack, or Eurycoma longifolia is a
common herbal shrub found along the slopes of hilly ter-
rains in the Malaysian rainforests (Malaysian Monograph
Committee, 1999; Bhat and Karim, 2010). Its medicinal
value relates to the ground where it is found, and higher
concentrations of phytochemical compounds are found
in the Malaysian Peninsular TA when compared with
TA found elsewhere.
Eurycoma longifolia roots contain a wide variety of
chemical compounds including eurycomaside, tannins,
high molecular weight polysaccharides, glycoproteins,
and mucopolysaccharides, as well as alkaloids of the
quassinoid group (Morita et al., 1993; Jiwajinda et al.,
2001; Ang et al., 2002; Bedir et al., 2003; Miyake et al.,
2009). The active components of TA have been shown
to exert a testosterone-increasing effect (Ali and Saad,
1993; Sambandan et al., 2006; Asiah et al., 2007; Chan
et al., 2009; Tambi et al., 2011). The androgenic effect
of increased serum testosterone is increased muscle
mass, therefore increased potential for generating
greater force in the muscles, evidenced by enhanced
strength (Hamzah and Yusof, 2003). Moreover, TA has
been shown to be a potent herbal energizer (Tambi,
2006a, 2006b), aphrodisiac, pro-fertility, and antiaging
treatment (Ang and Sim, 1998a, 1998b; Ang et al.,
2000; Ang and Ngai, 2001; Tambi, 2005, 2006a, 2006b).
As a result of these known effects of TA, specif ically on
serum testosterone levels, a few studies have investigated
its ergogenic effects on exercise performance in terms of
strength (Bhasin et al., 1996; Hamzah and Yusof, 2003)
and endurance capacity (Ooi et al., 2001, 2003; Muhamad
et al., 2009, 2010). One of the effects of aging is decreased
testosterone levels. Declining testosterone is linked to
loss of muscle mass and muscle strength. Men lose more
muscle mass and strength than women as they age,
suggesting that testosterone contributes to these changes
in physical function (Vermeulen, 2000).
As TA has been shown to enhance serum testosterone
levels, muscle strength should be enhanced, which would
in turn assist elderly people to become or remain physically
active. This study aimed to investigate the usefulness of TA
as an ergogenic supplement to strengthen the muscles of
elderly people.
METHODS
Study design and participants. This was a comparative
study investigating the effects of TA supplementation on
* Correspondence to: Ralf Henkel, Department of Medical Bioscience,
University of the Western Cape, Bellville 7535, South Africa.
E-mail: rhenkel@uwc.ac.za
†
Ralf R. Henkel and Ruxiang Wang contributed equally.
PHYTOTHERAPY RESEARCH
Phytother. Res. 28: 544–550 (2014)
Published online 11 June 2013 in Wiley Online Library
(wileyonlinelibrary.com) DOI: 10.1002/ptr.5017
Copyright © 2013 John Wiley & Sons, Ltd.
Received 05 March 2013
Revised 18 April 2013
Accepted 08 May 2013

various blood parameters taken before supplementation
began and repeated after 3 and 5weeks, respectively.
The participants comprised a total of 25 seniors (13 male
and 12 female), aged between 57 and 72 years, all of
whom were members of a local amateur senior cycling
club in Shenyang, China. Ethical clearance was received
from the Ethics Committee of the Shenyang Center for
Disease Control and Prevention. All volunteers gave
their written informed consent to participate in this study.
Procedure. Supplementation consisted of 400 mg of a
patented (US Patent: 7,132,117) standardized water-
soluble extract of TA (Physta
™
; Biotropics Malaysia
Berhad, Kuala Lumpur, Malaysia) (200 mg taken twice a
day), for 5 consecutive weeks. A resting, fasting blood
sample was drawn in the morning before the treatment
began (baseline) and after 3 and 5 weeks, respectively. To
assess muscular strength, a simple handgrip dynamometer
test was performed before each blood test. To avoid any
bias with regard to circadian fluctuations of hormonal
levels, medical examination and collection of the blood
samples were always carried out at the same time.
Considering the age of the participants, it was expected
that many of them would have chronic diseases such as
heart disease, high blood pressure, and diabetes, but they
were not excluded because the subjects were physically
active, cycling each day. Because TA is a traditional
remedy, it has been commonly used by many people for
centuries in Southeast Asia, but no studies on possible
contraindications or side effects are available. Participants
were allowed to take the supplement along with their usual
medications. In addition, participants were requested
not to change their normal dietary habits during the time
of supplementation.
The effect of TA supplementation on the levels of
selected hormones, red blood cells (RBCs) and hemoglobin
(HGB), blood urea nitrogen (BUN) level, and creatine
kinase (CK) level of the senior cyclists was evaluated.
Specifically, the following standard blood parameters
were taken: RBC count, HGB concentration, hematocrit
(HCT), white blood cell count, and platelet concentration.
As hormonal parameters, total and free testosterone,
dihydroepiandrosterone-sulfate, and cortisol were examined
in the serum samples. As parameters related to exercise, the
concentrations of BUN, CK, the mean corpuscular HGB,
mean corpuscular HGB concentration, red cell distribution
width, microcorpuscular volume, and the ratio of free
testosterone/cortisol (T/C) were measured. Finally, insulin-
like growth factor-1 and sex hormone-binding globulin
(SHBG) were evaluated. All tests were carried out in
the clinical laboratory according to standard procedures.
To assess the aging health and sexual health of the
subjects, the male participants were asked to f ill out
the Aging Males’Symptoms (AMS) questionnaire
according to Heinemann et al. (1999) before and after
the treatment (Table 1). For the female participants, a
similar questionnaire was developed as Aging Females’
Symptoms (AFS) (Table 2). Additionally, a comment
form on the herbal treatment was completed at the
end of the trial, in order to determine if there were
any side effects experienced (Table 3).
Statistical analysis. Statistical analysis of the data was
performed by using MedCalc version 12.0.1 (MedCalc
Software, Mariakerke, Belgium). Data were expressed
as mean SD. After testing for normal distribution by
means of the Kolmogorov–Smirnov test, parametric
tests, analysis of variance (ANOVA) trend analysis,
and Student’st-test as well as Fisher’s exact test and
McNemar test were applied. p-values of less than 0.05
were considered significant.
RESULTS
Summary statistics of the study
The patient interviews and physical examinations revealed
that the treatment with 400-mg TA daily for 5 consecutive
Table 1. Answers of male participants to Aging Males’Symptoms questionnaire before and after the 5-week treatment period
Symptoms
Before After
012 3 01 2 3
Decline in your feeling of general well-being 2 3 8 2 5 6
Joint pain and muscular ache 3 4 3 3 3 5 5
Excessive sweating 7 4 2 8 5
Sleep problems 4 5 4 6 5 2
Increased need for sleep, often feeling tired 3 7 3 2 5 6
Irritability 2 7 4 2 9 2
Nervousness 6 5 2 6 7
Anxiety 3 4 4 2 4 6 3
Physical exhaustion/lacking vitality 1 6 6 4 8 1
Decrease in muscular strength 2 5 6 3 8 2
Depressive mood 2 5 4 2 5 4 4
Feeling that you have passed your peak 6 5 2 6 6 1
Feeling burnt out, having hit rock bottom 2 8 3 7 6
Decreased in beard growth 5 6 2 7 5 1
Decrease in ability/frequency to perform sexually 4 9 9 4
Decrease in the number of morning erections 8 5 2 10 1
Decrease in sexual desire/libido 3 10 8 5
0, none; 1, mild; 2, moderate; 3, severe; Fisher’s exact test, p= 1.0; McNemar test, p= 0.1021.
545TONGKAT ALI AS ERGOGENIC SUPPLEMENT
Copyright © 2013 John Wiley & Sons, Ltd. Phytother. Res. 28: 544–550 (2014)

weeks resulted in no side effects in any of the subjects.
Tables 4 and 5 summarize the results of the clinical and
biochemical parameters of the male and female partici-
pants in the study, respectively. The ages of both examina-
tion groups, male and female, were matching (male:
65.9 4.8 years; female: 63.1 4.0 years; and p= 0.1231).
Differences between male and female participants
As expected, before the treatment, female subjects
showed significantly lower values of HGB concentration
(p= 0.0046), white blood cell count ( p=0.0326), total
and free testoster one concentrations ( p<0.0001),
dihydroepiandrosterone concentration ( p=0.0097), the
ratio of total testosterone to cortisol ( p<0.0001), and
muscle strength ( p= 0.0005), as determined by the force
achieved in the handgrip test, compared with the values
of the male participants. For the erythrocyte count
(p= 0.0599) and the HCT ( p= 0.0518), the female partic-
ipants in the study had lower, but not significant,
values than the male participants. In contrast, the serum
concentration of SHBG was significantly ( p=0.0370)
higher in the female participants than in the male
participants.
Effect of Tongkat Ali in female participants
After 5 weeks of treatment with TA, the differences in the
HGB ( p<0.0001), total and free testosterone ( p<
0.0001), and dihydroepiandrosterone concentrations
(p= 0.0398), the ratio of total T/C ( p<0.0001), and the
muscle force as determined in the handgrip test ( p<
0.0001) remained significantly lower in female partici-
pants than in male participants. Additionally, the HCT
and RBC count in the male participants increased
slightly, thus reaching significance when compared with
those levels measured in the female participants
(p= 0.0001 and p= 0.0009, respectively).
Whereas the SHBG levels in the male participants
remained unc hanged ( p= 0.3647) after 5 weeks of
treatment with TA, the serum SHBG concentration in
the female participants decreased significantly ( p<
0.0001) by 20.8% to levels comparable with male partici-
pants (Tables 4 and 5). As a result, no difference
(p= 0.5493) between the serum SHBG levels in male
and female participants was observed.
For the femaleparticipants inthe study, total (ANOVA
trend analysis: p= 0.0098) and free testosterone (ANOVA
trend analysis: p= 0.0001) concentrations and muscle
force (ANOVA trend analysis: p= 0.0641) increased
Table 2. Answers of female participants to Aging Females’Symptoms questionnaire before and after the 5-week treatment period
Symptoms
Before After
01230 1 23
Heart discomfort 9 2 10 1
Sleep problems 3 7 1 5 6
Depressive mood 4 3 4 6 4 1
Irritability 5 3 3 5 5 1
Anxiety 7 4 9 2
Physical and mental exhaustion 7 3 3 3 5 3
Sexual problems 7 4 2 7 2
Bladder problems 2 4 3 2 3 5 2 1
Dryness of vagina 4 5 2 4 7
Joint and muscular discomfort 3 2 5 1 4 5 2
0, none; 1, mild; 2, moderate; 3, severe; Fisher’s exact test, p= 0.004; McNemar test, p= 0.0017.
Table 3. Answers to the general questions after the trial
Yes N o
Question Male (n= 13) % Female (n= 11) % Male (n= 13) % Female (n= 11) %
Do you think the supplement is helpful
to your health?
13 100 11 100
Do you feel any improvement in your
desire to actively exercise?
8 61.54 9 81.82 5 38.46 2 18.18
Did you feel any improvement in your
endurance capacity for exercise?
7 53.85 8 72.72 6 46.15 3 27.27
Do you want to continue to use this
supplement?
13 100 11 100
Did you feel hot after taking the supplement? 13 100 11 100
Did you feel dry in your mouth after taking
the supplement?
13 100 11 100
Did you feel a slight headache after taking
the supplement?
13 100 11 100
546 R. R. HENKEL ET AL.
Copyright © 2013 John Wiley & Sons, Ltd. Phytother. Res. 28: 544–550 (2014)

Table 4. Effect of Tongkat Ali on clinical and biochemical parameters in men before (baseline), after 3 weeks, and at the end (5 weeks) of
the treatment
Variable (n=13) Baseline 3 weeks 5 weeks (5 week)
p-value
Baseline versus
3 weeks
Baseline versus
5 weeks
Red blood cell count (10
6
/mL) 4.76 0.46 4.89 0.44 4.95 0.35 0.4163 0.1235
Hemoglobin concentration (g/L) 124.00 11.93 129.09 7.45 131.58 8.07 0.0603 0.0093*
Mean corpuscular hemoglobin (pg) 25.36 2.76 26.83 1.26 25.693.85 0.1365 0.8302
Mean corpuscular hemoglobin
concentration (g/L)
261.75 18.05 277.0913.31 273.60 8.67 0.1041 0.1275
Hematocrit (%) 46.193.56 46.73 4.02 47.81 2.60 0.6269 0.1624
Red cell distribution width (%) 14.55 0.24 14.62 0.49 14.66 0.50 0.6061 0.4990
White blood cells count (10
6
/mL) 6.37 1.46 6.14 1.48 6.17 1.38 0.5793 0.4287
Platelets (PLT/L) 143.92 26.91 122.63 24.68 142.6424.61 0.0854 0.8590
Microcorpuscular volume (fL) 95.91 4.74 96.91 4.85 97.36 5.22 0.5356 0.4746
Blood urea nitrogen (mmol/L) 14.98 4.28 16.50 3.43 18.96 3.13 0.4401 0.0117*
Creatine kinase (U/L) 201.72 166.71 112.6836.24 114.11 60.52 0.0887 0.0415*
Total testosterone (ng/mL) 3.84 0.79 4.09 1.02 4.42 1.15 0.2405 0.0090*
Free testosterone (pg/mL) 5.20 1.60 5.99 1.62 8.38 2.18 0.0459* 0.0005*
Dihydroepiandrosterone (mg/mL) 180.55 104.80 197.64 101.48 179.44 101.29 0.5285 0.9603
Cortisol (ng/mL) 201.56 49.34 177.26 41.92 201.69 55.61 0.0650 0.9916
Ratio total testosterone/cortisol 0.020 0.006 0.024 0.007 0.023 0.007 0.0320* 0.0533
Insulin-like growth factor-1 (ng/mL) 174.75 48.39 181.54 32.04 169.21 29.43 0.8645 0.7674
Sex hormone-binding globulin (nmol/L) 45.58 14.61 39.08 13.32 43.01 18.14 0.0776 0.3647
Handgrip test (kg) 46.03 11.30 55.27 11.00 53.67 9.86 0.0135* 0.0375*
*Significant at p<0.05.
Table 5. Effect of Tongkat Ali on clinical and biochemical parameters in women before (baseline), after 3 weeks, and at the end (5 weeks)
of the treatment
Variable (n=12) Baseline 3 weeks 5 weeks
p-value
Baseline versus
3 weeks
Baseline versus
5 weeks
Red blood cell count (10
6
/mL) 4.45 0.28 4.35 0.32 4.41 0.31 0.2309 0.7551
Hemoglobin concentration (g/L) 111.27 6.10 111.467.72 113.91 8.19 0.9264 0.2358
Mean corpuscular hemoglobin (pg) 24.96 0.75 25.66 0.85 25.65 1.33 0.0509 0.0999
Mean corpuscular hemoglobin
concentration (g/L)
265.09 9.79 274.09 9.55 271.54 5.28 0.0295* 0.1305*
Hematocrit (%) 42.74 4.46 41.07 3.18 41.94 2.88 0.2200 0.5637
Red cell distribution width (%) 14.41 0.51 14.34 0.51 14.27 0.59 0.7089 0.3946
White blood cell count (10
6
/mL) 5.20 0.89 5.28 0.76 5.17 0.87 0.6214 0.9113
Platelets (PLT/L) 149.82 27.09 121.82 32.41 125.73 26.90 0.0112* 0.0116*
Microcorpuscular volume (fL) 94.46 3.91 94.54 4.27 109.73 28.67 0.8213 0.1173
Blood urea nitrogen (mmol/L) 14.66 4.04 15.47 4.66 16.82 3.66 0.3949 0.1988
Creatine kinase (U/L) 125.72 73.78 103.93 45.05 81.52 31.14 0.0765 0.0924
Total testosterone (ng/mL) 0.35 0.17 0.44 0.19 0.52 0.30 0.0284* 0.0098*
Free testosterone (pg/mL) 0.50 0.24 0.66 0.38 1.11 0.66 0.0353* 0.0032*
Dihydroepiandrosterone (mg/mL) 88.79 37.09 117.53 77.68 105.63 61.45 0.1019 0.2870
Cortisol (ng/mL) 176.59 54.34 171.42 26.27 187.02 35.90 0.7628 0.4761
Ratio total testosterone/cortisol 0.002 0.001 0.003 0.001 0.003 0.002 0.2482 0.1380
Insulin-like growth factor-1 (ng/mL) 145.27 49.97 134.39 32.93 145.70 43.48 0.3683 0.9694
Sex hormone-binding globulin (nmol/L) 59.66 17.18 50.39 15.85 47.26 16.65 0.0009* <0.0001*
Handgrip test (kg) 29.61 7.28 36.87 8.03 33.67 8.38 0.0069* 0.0641*
*Significant at p<0.05.
547TONGKAT ALI AS ERGOGENIC SUPPLEMENT
Copyright © 2013 John Wiley & Sons, Ltd. Phytother. Res. 28: 544–550 (2014)

significantly by 48.6%, 122%, and 13.7%, respectively.
In contrast, significant declines were observed for the
concentration of platelets (decline by 16.1%; ANOVA
trend analysis: p= 0.0116) and SHBG (decline by 20.8%;
ANOVA trend analysis: p<0.0001). Whereas the evalua-
tion of the AFS score revealed significant improvements
(Fisher’s exact test: p= 0.0040; McNemar test: p= 0.0017),
all other clinical and biochemical parameters were not
influenced by the treatment (Table 2).
Effects of Tongkat Ali in male participants
In men, treatment with TA for 5 weeks resulted in the
significant increases in total (ANOVA trend analysis:
p= 0.0195) and free (ANOVA trend analysis: p=0.0001)
testosterone concentrations and muscular force, as deter-
mined by the handgrip test (ANOVA trend analysis:
p= 0.0602), by 15.1%, 61.1%, and 16.6%, respectively.
In addition, significant increases in the BUN (ANOVA
trend analysis: p= 0.0190) and HGB concentrations
(ANOVA trend analysis: p= 0.0188) by 26.6% and 6.1%,
respectively, were observed. In contrast, CK activity
declined by 43.4% (Table 1), but in the ANOVA trend
analysis, this was not signif icant ( p= 0.9472). All other
clinical and biochemical parameters remained unchanged.
Evaluation of the AMS questionnaire did not reveal any
significant changes (Fisher’s exact test: p=1.0; McNemar
test: p= 0.1021) (Table 1).
Satisfaction survey
The feedback given by the patients after the treatment
(Table 3) generally revealed affirmative answers, thus
indicating that the treatment subjectively improved the
participants’wellness and capacity to do physical exercise.
DISCUSSION
To the best of our knowledge, this is the first study on
TA that evaluates the wellness trend in physically active
seniors. The sample size of the study was small because
of recruitment difficulties, but the subjects recruited
were a very enthusiastic group. They were physically
active, cycling each day, and many of them had chronic
diseases such as heart disease, high blood pressure,
and diabetes and took medicines along with the herbal
supplement. It was noted that the difference in health
conditions and the medicines each subject took some-
what influenced the result. This could probably explain
why the results for some hormone levels in the fifth
week were not as good as in the third week.
Effect on serum testosterone levels
As expected (Tambi et al., 2011), serum testosterone con-
centrations increased significantly in men, but, interest-
ingly, both total and free testosterone also increased
significantly in female participants by 48.6% and 122%
after 5 weeks, respectively. This high increase in free
bioavailable testosterone in female participants cannot
be explained only by the higher concentrations of total
testosterone. Most probably, the decline in serum SHBG
concentrations contributed to the increase in free testos-
terone in female participants. Although significantly
elevated after the treatment with TA, the testosterone
levels (total and free testosterone) in the female partici-
pants were still well within normal physiological levels
of 0.063–0.836 ng/mL and 1.0–8.5 pg/mL, respectively.
Thus, it appears that a potential abuse by athletes (Myhal
and Lamb, 2000) need not be considered.
Muscle strength and potential damage
Even though muscle size was not measured as a parame-
ter, the increase in muscle force, as determined by the
handgrip test, in both genders indirectly reflected an
increased muscle mass and was directly linked to the
significant increase in total and free testosterone concen-
trations. Thus, this study confirms the observations by
Bhasin et al. (1996) as well as Hamzah and Yusof (2003).
In addition, despite the participants being active cyclists,
results demonstrate that the muscles were not being
damaged by the exercise, as evidenced by the drop in
CK enzyme levels (significantly for men). CK is an enzyme
that is released from injured or dying muscle cells and is
therefore regarded as an indicator of muscle damage
(Jones et al., 1986). Furthermore, this study shows that
the ergogenic effects are not only limited to men but also
occur in elderly women, because the serum testosterone
concentrations also increased in the female group.
Nevertheless, this decrease in muscle damage is
accompanied by an increase in BUN levels, which indi-
cates either increased protein catabolism or decreased
kidney function or both. In the urea cycle, nitrogen from
muscle and enteral proteins is converted into urea
(Halperin and Rolleston, 1993). The results of this study
revealed a significant increase in BUN for men over the
5 weeks of TA supplementation and a nonsignificant
increase in women. Considering that, under anabolic
conditions, muscle mass is built up instead of metabolized
and that muscle damage due to exercise after the treat-
ment with TA was decreased, it is unlikely that muscle
protein was being used to produce energy during the
course of this study. Therefore, the BUN levels observed
in this study should be regarded as an indicator of kidney
function (Kuroda et al., 2012) rather than protein catabo-
lism. However, the BUN levels observed in this study,
even after the treatment, were still well within normal
range, and a cause for this increase cannot be explained
by the current data.
Concentration of Tongkat Ali and duration of treatment
On the other hand, other authors did not find any
beneficial effects of TA extract on endurance running ca-
pacity and cycling after administration of either an herbal
ergogenic drink containing 0.001-mg TA/mL (Ooi et al.,
2001, 2003) during the exercise or two TA capsules
(75 mg TA per capsule) daily for 7 days before the
exercise (Muhamad et al., 2010). These authors suggest
that either the total dosage of TA administered was too
low or the period of TA supplementation was too short.
This argument is supported by the current study, where
various parameters show clear trends, either positive or
negative, with the duration of the treatment.
548 R. R. HENKEL ET AL.
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Effect on hematological parameters
Tongkat Ali had a positive effect on serum HGB con-
centration ( p<0.05 for men). However, no aerobic
measures were taken in the study with which to deter-
mine whether this had a benef icial ergogenic effect.
Although HGB concentration relates directly to the
oxygen-carrying capacity of the blood, one also has to
consider the muscles’ability to take up and use this
oxygen to produce adenosine triphosphate. This result is
in contrast to those described by Muhamad et al.(2010)
who did not find any influence of TA supplementation
on HGB concentration and HCT. Once again, this might
be due to the period of TA administration being too short
and/or the dose being too low. Similarly, Ooi et al.(2001,
2003) and Muhamad et al. (2009, 2010) have studied the
effects of TA on cycling and running performance and
noted no beneficial effects of acute supplementation,
perhaps because of the dosage being too low. However,
the fact that increased HGB concentrations were seen in
this study warrants further investigation.
Benefits of Tongkat Ali supplementation
During exercise, testosterone and cortisol are affected in
opposite ways, resulting in a change of the hormonal
status from a catabolic state, dominated by cortisol,
toward an anabolic state, dominated by testosterone
(Adlercreutz et al., 1986). Therefore, as a measure to
determine the anabolic/catabolic status of a muscle
during training, the calculation of the T/C ratio has been
suggested (Hakkinen, 1989). The ratio diminishes with
increasing training load and performance capacity
(Hoogeveen and Zonderland, 1996; Mujika et al., 1996)
and is regarded as an indication of overtraining and
fatigue if it decreases below a cutoff level (Adlercreutz
et al., 1986; Hakkinen and Pakarinen, 1991).
In the present study, relevant changes in this parameter
were only observed in men, where a clear trend toward
a higher value after administration of TA was evident.
For women, although a slight increase was observed,
the changes were not significant. Considering that the
increased T/C ratio in men is due to the significantly
increased testosterone levels, this indicates that TA
increases the body’s anabolic status. For elderly men,
hypogonadotropic or infertile patients, this is beneficial
(Tambi and Imran, 2010; Tambi et al., 2011), as it improves
libido, fertility, and well-being (Vermeulen, 2000).
In men, aging symptoms (AMS) in terms of the
questionnaire did not change as one would expect
(Tambi et al., 2011), which was most probably due to
the small sample size. Interestingly, in the female partic-
ipants of the study, the aging symptoms (AFS) improved
significantly. In the literature, information on such an
effect of TA in women is not available. On the contrary,
Wah ab et al. (2010) suggested that TA extract would act as
a potential agent that reverses the inhibitory effects of
estrogen on spermatogenesis in male rats. Unfortunately,
serum estrogen and progesterone concentrations were
not taken as parameters in this study. Therefore, this result
warrants further investigation to elucidate potential
beneficial effects of TA, which, thus far, is said to have
beneficial effects in respect of the well-being in men
(Tambi, 2006a, 2006b) and also in women.
In conclusion, this observational study on the effect of
a standardized water-soluble extract of TA has shown
that the herbal supplement had no adverse effects and
is acceptable to the senior recreational athlete as a form
of health supplement for general well-being. The study
has affirmed the ergogenic benefit of TA for physically
active seniors and has the potential to assist the elderly
to exercise, thereby enhancing health and wellness,
through enhanced muscle strength.
Acknowledgement
The authors wish to thank Biotropics Malaysia Berhad, Kuala
Lumpur, Malaysia, for financially supporting this study.
Conflict of Interest
The authors declare not to have any conflict of interest.
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