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Laura Bystrom, PhD
Amy Keller, PhD
Mariann Garner-Wizard
Cheryl McCutchan, PhD
Executive Editor – Mark Blumenthal
Shari Henson
Heather S Oliff, PhD
Managing Editor – Lori Glenn
Consulting Editors – Thomas Brendler, Francis Brinker, ND, Allison McCutcheon, PhD, J. Erin Smith, MSc, Carrie Waterman, PhD
Assistant Editor – Tamarind Reaves
File: ■ Tongkat Ali (Eurycoma longifolia, Simaroubaceae)
■ Testosterone
■ Renal and Liver Function
HC 091434-517
Date: March 31, 2015
RE: Tongkat Ali Does Not Affect Testosterone:Epitestosterone Ratio or Liver and
Kidney Function after Six Weeks of Supplementation in Recreational Athletes
Chen CK, Mohamad WMZW, Ooi FK, Ismail SB, Abdullah MR, George A.
Supplementation of Eurycoma longifolia Jack extract for 6 weeks does not affect urinary
testosterone: epitestosterone ratio, liver and renal functions in male recreational
athletes. Int J Prev Med. 2014;5(6):728-733.
Testosterone supplementation to enhance athletic performance is prohibited in sports
and is detected using urine tests that quantify the ratio of testosterone to epitestosterone
(T:E). The traditional medicine and reputed aphrodisiac Eurycoma longifolia (EL;
Simaroubaceae), commercially known as Tongkat Ali in Malaysia, has been shown to
elevate serum testosterone1,2 and increase muscle strength in humans.3 This 6-week,
double-blind, placebo-controlled, crossover study evaluated the effects of a proprietary
standardized EL extract (Physta®; Biotropics Malaysia Berhad; Shah Alam, Selangor,
Malaysia) on T:E ratio and liver and renal function in male recreational athletes. The
characteristics of Physta were not described in the article. According to the company
website, Physta contains 0.8-1.5% eurycomanone, ˃22% total protein, ˃30% total
polysaccharide, and ˃40% glycosaponin (http://www.biotropicsingredients.com/physta/).
This study was funded by Biotropics Malaysia Berhad and one of the authors is an
employee of the company.
Enrolled in the study were 13 healthy male recreational athletes (average age 29.0 ± 5.5
years) with a maximum oxygen consumption of 51.7 ± 6.8 mL/kg/min and no history of
liver or kidney disease.The subjects consumed either 400 mg of Physta or placebo
(maltodextrin) daily for 6 weeks during the first supplementation period. After a 3-week
washout period, they consumed the alternate supplement for another 6 weeks.
At baseline and at the end of each 6-week supplementation period, subjects reported to
the Sports Science Laboratory at the Universiti Sains Malaysia in Kelantan, Malaysia to
provide urine and blood samples.
After the 6-week intervention, T:E ratios did not significantly change in either group, and
no statistically significant between-group differences were observed. Similarly, there
were no statistical differences in liver or kidney function tests after either intervention.
The few trials investigating the effect of EL on athletic performance have produced
conflicting results. Acute EL supplementation at a low dosage (0.67 mg per trial) 30
minutes prior to exercise did not improve endurance cycling capacity among young
cyclists in a thermoneutral environment4; nor did an increased dosage (150 mg daily for
7 days) provide any beneficial effect on endurance training.5 In those studies, "it is
possible that the duration and dosage of supplementation was not sufficient to affect
performance," write the authors. Another trial found that 100 mg/day of EL for 5 weeks
increased fat free mass and muscle strength and size in healthy adult males.3
In summary, supplementation for 6 weeks with 400 mg/day of EL did not significantly
affect T:E ratios, nor did it have any adverse effects on liver and kidney function. The
authors conclude that future studies with even higher dosages and longer
supplementation periods are warranted, not only to assess the effect of EL on athletic
performance but also to ensure that it does not pose any doping or safety issues.
Nevertheless, it is noted that dosages as low as 100 mg/day of EL have already shown
an improvement in muscle strength and size.
—Shari Henson
Taxonomic Note:
The authors of this article (and others) erroneously refer to Tongkat Ali as Eurycoma
longifolia Jack (ELJ). The accepted scientific name is Eurycoma longifolia. "Jack" is the
authority for this Latin binomial (the authority is the person who first assigned the
scientific name to the species; in this case, William Jack in 1822).
References
1
Tambi MIM. Water soluble extract of Eurycoma longifolia in enhancing testosterone in males. Proceedings
of the SupplySide West International Trade Show and Conference; October 1-3, 2003; Las Vegas, Nevada.
2
Tambi MIBM, Imran MK, Henkel RR. Standardised water-soluble extract of Eurycoma longifolia, Tongkat
ali, as testosterone booster for managing men with late-onset hypogonadism? Andrologia. 2012;44(Suppl
s1):226-230.
3
Hamzah S, Yusof A. The ergogenic effects of Eurycoma longifolia Jack: A pilot study. Br J Sports Med.
2003;37:465-466.
4
Ooi FK, Singh R, Sirisinghe RG, Ang B, Jamalullail S. Effects of a herbal ergogenic drink on cycling
performance in young cyclists. Malays J Nutr. 2001;7(1):33-40.
5
Muhamad AS, Chen CK, Ooi FK, Abdullah MR, Lam CK. Effects of Eurycoma longifolia Jack
supplementation on recreational athletes' endurance running capacity and physiological responses in the
heat. International Journal of Applied Sports Sciences. 2010;22(2):1-19.
Referenced article can be found at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4085925/.
The American Botanical Council provides this review as an educational service. By providing this service, ABC does not warrant
that the data is accurate and correct, nor does distribution of the article constitute any endorsement of the information contained or of
the views of the authors.
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