Lack of effect of Tribulus terrestris on muscle strength in rugby league players

The good news? There’s no risk of a positive test for doping.

First, the details.

  • 22 Australian elite male rugby league players were randomly assigned to take T. terrestris (puncture vine) extract (450 mg/day) or placebo capsules once daily for 5 weeks.
  • Neither the researchers nor volunteers knew their treatment.
  • All volunteers performed structured heavy resistance training as part of the club’s preseason preparations.

And, the results.

  • After 5 weeks of training, strength and fat-free mass increased significantly, but there were no differences between the group.
  • There was no difference in the urinary testosterone/epitestosterone (T/E) ratio, which may place athletes at risk of a positive drug test.

The bottom line?
The authors concluded, “T. terrestris did not produce the large gains in strength or lean muscle mass that many manufacturers claim can be experienced within 5 to 28 days. Furthermore, T. terrestris did not alter the urinary T/E 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.

Body building websites typically claim that T. terrestris “boosts” testosterone levels. “Boost” is your first clue that the drug is useless. These study results provide your second clue.

9/25/07 15:03 JR

Hi, I’m JR

John Russo, Jr., PharmD, is president of The MedCom Resource, Inc. Previously, he was senior vice president of medical communications at www.Vicus.com, a complementary and alternative medicine website.