Tribulus is a plant extract that has been used for centuries in Indian and Chinese medicine to treat illness, boost energy, and increase libido. In the 1990s, tribulus became popular with bodybuilders as a natural, safe testosterone-booster. Sometimes bodybuilders combine tribulus with other supplements or hormones to maximize the strength- and muscle-building effects of each substance. This type of combination is called a tribulus stack. The most common stacks are tribulus with DHEA, and tribulus with ZMA, which is zinc mononethionine aspartate, magnesium aspartate, and vitamin B6.
Among the bodybuilding community, it is thought that tribulus increases levels of luteinizing hormone, known as LH, which stimulates production of testosterone, a hormone associated with building strength and muscle mass. Its growth in popularity is due to the belief that it works well, and in a safe, natural, and legal manner. Tribulus is not considered a banned substance by the International Olympic Committee.
There have been a few studies on the effectiveness of this extract. Many have been performed on animals. The few studies that tried to show tribulus’ effect on strength and muscle development in humans had flaws that led some researchers to criticize the results. Although a few studies showed that tribulus has an aphrodisiac effect in animals, no recognized studies have shown it to have strength-building properties in humans.
Despite a lack of evidence for the effectiveness of tribulus, many athletes continue to use it. Tribulus is a neutral substance that does not hinder the effects of other supplements, making it a popular ingredient for stacking. DHEA is a hormone also known as 5-Dehydroepiandrosterone that is commonly stacked with tribulus. As a precursor to the sex hormones, DHEA has a similar effect on the body to anabolic steroids.
Athletes use a DHEA-tribulus stack in the belief that the combination of substances helps with muscle building and recovery better than either substance on its own. Many sports organizations have DHEA on lists of banned substances. Although DHEA has been shown in studies to be effective for other medicinal and supplemental uses, its effect on building strength has not been proven.
Some bodybuilders use a ZMA-tribulus stack to maximize muscle gains and recovery. During intense exercise, the muscles may become depleted of zinc and magnesium which limits recovery. Supplementing with ZMA is believed to help replenish stores of the minerals so that the muscles can continue to develop and increase in strength at a fast rate. Since ZMA is composed of minerals, it makes up a legal tribulus stack for athletes.