Though tribulus terrestris has long been a constituent in tonics in Indian ayurveda practice, it is now a popular herbal nutritional supplement that is marketed as an ingredient to produce large gains in strength and lean muscle mass in people who engage in resistance training or weight lifting. Does tribulus terrestris actually work to help athletes to promote gains in strength or lean muscle mass?
A recent study, published in the Journal of Strength and Conditioning Research, studied the effects of Tribulus terrestris extract on muscular strength, body composition, and urinary T/E (testosterone/epitestosterone) ratio in elite Australian male rugby players.
Dose: T. terrestris extract (450 mg/d or placebo capsules were consumed once daily for 5 weeks.
Note: All subjects performed structured heavy resistance training as part of the club’s preseason preparations.
Conclusions:
“It was concluded that T. terrestris did not produce the large gains in strength or lean muscle mass that many manufacturers claim can be experienced within 5-28 days. Furthermore, T. terrestris did not alter the urinary T/E (testosterone/epitestosterone) ratio and would not place an athlete at risk of testing positive based on the World Anti-Doping Agency’s urinary T/E ratio limit of 4:1.”
The results of this study are consistent with the results of a previous study which was published in the International Journal of Sports Nutrition and Exercise Metabolism (Antonio et al, 2001), which concluded, “supplementation with tribulus does not enhance body composition or exercise performance in resistance-trained males.”
References:
Rogerson S, Riches CJ, Jennings C, Weatherby RP, Meir RA, Marshall-Gradisnik SM. The effect of five weeks of Tribulus terrestris supplementation on muscle strength and body composition during preseason training in elite rugby league players. J Strength Cond Res. 2007 May;21(2):348-53.
Antonio J, Uelmen J, Rodriguez R, Earnest C. The effects of Tribulus terrestris on body composition and exercise performance in resistance-trained males. Int J Sport Nutr Exerc Metab. 2000 Jun;10(2):208-15.
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8 Comments
September 8, 2008 at 10:56 pm
Great post! I agree completely with this and have seen no human research that demonstrated “testosterone increasing effects” with this herb. It is one of the common herbs used in many test formulas but has no reason for inclusion.
September 8, 2008 at 11:23 pm
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September 13, 2008 at 12:21 am
Thank you for your comment, Scott. I see that Tribulus has stimulated quite the discussion on your blog. For my blog readers, click the link below to read more about the tribulus debate:
http://www.supplementgenius.com/2008/09/08/does-tribulus-really-work/
September 21, 2008 at 5:50 pm
I have used tribulus (and am currently using it now) and I can say that I have definitely noticed an improvement in strength. Depending upon the brand you use and whether they are in pill or capsule form also makes a difference. I’m not sure about my actual test results as I have not gone to have my testosterone levels tested since about a year and a half ago, but I at least notice an increase in energy as well as in other areas. I also use other supplements such as creatine, l-arginine, and l-ornithine which all play their role, but I find tribulus to be helpful in the mix. I know that’s not very scientific but I wouldn’t write it off as completely ineffective. It seems to work for some people and have little effect on others.
September 21, 2008 at 8:21 pm
Andrew, thank you for your comment about tribulus. For my blog site, I simply highlight the latest research studies on various supplements and generally offer my opinion based on such info. Hopefully, this helps my blog readers to make a better informed decision on which supplements to use.
September 23, 2008 at 11:17 pm
I’m no statistics expert, but even a layman like me knows a bunch of elite rugby players is hardly a random segment of the population. So, Tribulus didn’t help peak-condition athletes enhance their performance levels. So what? What other supplements were they taking — legal and illicit — that may have compounded the studies effects? Did they alter their fitness regimen at all?
How about all the studies in which primates and other animals showed a 50% gain in testosterone levels? Or the body-building websites in which their is an overwhelming consensus among posters that tribulus increased exercise drive? Perhaps those rugby psychos already have maxed out testosterone.
I want to know how tribulus would effect a random sample of people. Did it make them want to get off the couch more often and exercise more frequently and harder?
Chris
September 24, 2008 at 3:46 am
Chris, thank you for your recent comment. Overall, there is no currently available published research which suggest that tribulis terrestris (tt) increases testosterone levels in humans. How closely elite rugby players approximate a random sample of people may be debatable. However, I can assure you that a group of rugby players is a closer approximation to a random sample of people than the research you refer to regarding primates, rabbits and rats.
To be certain, the study by Gauthaman K el al (2008), which I assume that you are referring to involved primates given an intravenous bolus injections of tt, castrated rats, and rabbits. The rabbits did not have a statistically significant elevation in testosterone levels. Only the castrated rats and the primates which were given i.v. bolus injections of tt experienced statistically significant increases in testosterone levels.
Generalizing data from this study has several problems including the assumption that an effect on one species will be the same on humans. Further, the rats studied were additionally castrated which also complicates things. The primates, as mentioned, were given a I.V. bolus injection which is an entirely different route of administration than tt supplements.
Here’s an additional study on tt in 21, young (20-36 year old men):
“The findings in the current study anticipate that Tribulus terrestris steroid saponins possess neither direct nor indirect androgen-increasing properties (Neychev et al, 2005).”
Neychev VK, Mitev VI. The aphrodisiac herb Tribulus terrestris does not influence the androgen production in young men. J Ethnopharmacol. 2005 Oct 3;101(1-3):319-23.Click here to read
Given that the current evidence for tt is lacking in humans, further research would be necessary to suggest that it has a role for athletes.
April 15, 2009 at 3:17 pm
I can tell that this is not the first time you write about this topic. Why have you chosen it again?