Tribulus terrestris, a flowering plant native to warm and tropical regions, is known by other names including puncture vine, yellow vine, and goat head among others. The extract is found in many common dietary supplement products with claims of increasing testosterone levels and thereby helping to build muscle and improve sexual performance. Though there is little evidence regarding the effectiveness of this extract, it is still widely used by many athletes.
Increase Muscle Mass
According to a study published in "The Journal of Strength and Conditioning Research," elite male rugby players who supplemented with 450 mg/d of tribulus terrestris extract for five weeks did not experience large gains in strength or muscle mass. In addition, the testosterone levels as measured by urinary excretion of the test subjects did not differ significantly from placebo users.
Increase testoserone levels
Another of the putative effects of supplementation with tribulus terrestris exract is that it is claimed to boost testosterone levels. Tribulus terrestris extract contains steroid saponins which were thought to mediate this effect. From a study published in "The Journal of Ethnopharmacology," young males who consumed 20 or 10mg of extract per kilogram of body weight for four weeks did not increase their androgen levels relative to placebo users.
Enhance exerise performance
From a clinical trial published in the "International Journal of Sports Nutrition and Exercise Metabolism," supplementation with 3.21mg of tribulus terrestris extract per kilogram of body weight for eight weeks did not enhance body composition or exercise performance in resistance-trained males. Overall, tribulus terrestris has not been studied extensively for enhancing athletic performance.
Side effects
There are few reported side effects of tribulus terrestris supplementation in the literature. Some users of this extract report minor side effects including stomach upset which may be relieved by taking it with food. Gynecomastia or breast enlargement occurs in males when they develop abnormally large mammary glands. Changes in the levels of androgens and estrogens or how your body responds to these hormones can result in gynecomastia. According to a case report in the journal "Breast," a young weight trainer developed gynecomastia after oral consumption of tribulus terrestris. Though this is a rare side effect, it is important to be aware of before you consider supplementation with tribulus terrestris extract.
References
- "Journal of Strength and Conditioning Research"; The effect of five weeks of Tribulus terrestris supplementation on muscle strength and body composition during preseason training in elite rugby league players; Shane Rogerson, Christopher J. Riches, Carl Jennsings, Robert P. Weatherby, Rudi A. Meier, Sonya M. Marshall-Gradisnik; May 2007
- "Journal of Ethnopharmacology"; The aphrodisiac herb Tribulus terrestris does not influence the androgen production in young men; V.K. Neychev, V.I. Mitev; October 2005
- "Breast"; Gynaecomastia and the plant product "Tribulis terrestris"; J.K. Jameel, P.J. Kneeshaw, V.S. Rao, P.J. Drew; October 2004
- "International Journal of Sports Nutrition and Exercise Metabolism"; The effects of Tribulus terrestris on body composition and exercise performance in resistance-trained males; J. Antonio, J. Uelmen, R. Rodriguez, C. Earnest; June 2000
- National Library of Medicine: Tribulus
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