Tribulus terrestris is a herb from Ayurveda. It is usually sold either as a libido or testosterone booster.

 

In regards to libido, there does seem to a positive effect. Sexual well being and erectile function were also reported to be higher after supplementation. The problem is that most studies were done on rats and there are very few human studies.

 

As for its effects on testosterone levels, there is no evidence that is does anything besides increase libido. Studies looking at sports performance and tribulus intakes have all failed to find any benefits while it has repeatedly failed to increase testosterone levels.

 

What this means is that tribulus terrestris might have a few positive applications (mostly in regards to libido), but does not seem to impact power output or testosterone levels.

 

It is not exactly known how tribulus works, but it might enhance androgen receptor density in the brain. Since this effect doesn’t seem to take place in the muscles the only confirmed effect is an increase in libido and not muscle growth.

 

There are also animal studies showing that the fruits of tribulus could protect certain organs (especially the liver and kidneys) from oxidative damages. This effect took place at fairly low dosages and will probably be further investigated in future studies.

There is no recommended dosage for tribulus. Standard doses for libido enhancement are between 200-450mg daily.

Tribulus supplements are generally safe when consume in normal doses. Studies lasted up to 90 days, so long term effects are still unknown.