Tribulus Terrestris is a herbal remedy used in general tonics for energy and impotence. It is also often in dietary supplements that are made to improve testosterone levels in bodybuilders and power athletes to help them build muscle mass and strength.

It is believed that by improving testosterone levels Tribulus Terrestris helps improve the blood levels of luteinizing hormone (LH). LH helps regulate natural testosterone production and serum levels.

It is believed that the active part of tribulus terrestris is furostanol saponins. Minimal research on tribulus’ ability to improve testosterone levels exists, although many body building products claim it does. Some cultures have traditionally used it to improve energy and deal with sexual dysfunction in males.

Animal studies show that tribulus might promote mounting behavior. There are a few European studies that have found tribulus to improve testosterone levels 30 to 50% above baseline levels, although this is still in the normal range. However, these studies also show increased estradiol levels, which is undesirable for hardcore muscle builders.

Since tribulus seems to improve testosterone levels only within normal levels, it could be useful for people that have lower testosterone levels including athletes susceptible to overtraining syndrome and people on long term low calorie diets. However, it does not make you suddenly grow muscle mass everywhere like some advertisements lead you think.

One of the few well-controlled studies on tribulus terrestris was of 15 resistance-trained males. This study focused on the effects tribulus had on body composition and exercise performance. The tribulus group used 1.5mg per pound of their body weight for a 2 month period. The study fond that the tribulus group did not show any extra changes to body weight, percentage fat, total muscle mass, or muscle strength when compared to the placebo group.

There does not seem to be any major side effects related to using tribulus in the amount it is present in supplements. However, some animal studies show that there are potential side effects of reduced muscle coordination when taken in high dosages, especially for a long period.

Tribulus is usually used as part of supplements that include other ingredients meant to improve muscle mass and strength in bodybuilders and athletes. It does not seem effective enough to use by itslef, but it might be useful when used in a supplement blend with other effective ingredients. It might help keep testosterone levels in the normal range. (Posted on 2/20/11)