The puncture vine is the green climbing plant known as tribulus, the abbreviated form of its botanical name, Tribulus terrestris, a leafy green climbing plant that grows in various parts of the United States, as well as in warm weather climates such as those of India and Sri Lanka. The tribulus is regarded as a noxious weed for agricultural purposes in most U.S. states.

Tribulus, or its regional variations, has been held in high regard in the ancient medical practices of India (where the herb is known as Gokshura in the Ayurveda holistic medical teachings) and the traditional Chinese medicines for many centuries. In both cultures, tribulus leaves were valued for their use in herbal formulations and tonics for the purpose of elevating mood, as well as to ease the discomfort caused to the digestive and urinary tracts by conditions such as colic. Tribulus was also believed to act as a remedy for male impotence in both cultures, as well working as an agent to alleviate the symptoms of menopause in women.

It is the connection believed to exist between the ingestion of tribulus and the increase in male sexual potency that has fueled a more recent interest in tribulus as a weight training supplement. The active chemical ingredient contained in the leaf of the tribulus plant is steroidal saponins, also known as furostanol. There has been a significant analysis of this chemical with respect to its impact, if any, on increased levels of testosterone within the body. Testosterone, the male sex hormone, is a key regulator of many important functions within the body, including the formation, development, and maintenance of muscle mass. Taken as a freestanding supplement to build greater strength, testosterone is a banned performance-enhancing substance in almost all international athletic competitions. Testosterone, when ingested as a training supplement, is classed as an illegal anabolic steroid by the World Anti-Doping Agency (WADA), given its muscle-building properties.

Tribulus and its active ingredient furostanol are not anabolic substances, as tribulus itself does not directly affect the growth of human muscle. The tribulus research has been focused on the relationship between tribulus ingestion and its impact on the chemical that occurs naturally in the human body, the luteinizing hormone (LH). LH plays an important role in the regulation and maintenance of testosterone levels in the body, which provided the theoretical basis for the proposition that a positive impact by tribulus on LH might itself increase levels of testosterone production. There has not been any conclusive scientific research to support the proposition that tribulus consumption will definitively increase testosterone production within the body. The chief difficulty with any determination that tribulus consumption raises testosterone levels is connected to the fact that all exercise will temporarily increase the production of testosterone. It is therefore difficult to scientifically differentiate between the purported effect of tribulus and the known effect of the exercise.

Tribulus adherents believe that the herb functions within the body in a similar fashion to that of creatine, in the sense that each substance acts as an agent that works to stimulate or precipitate a positive physiological effect in training, without acting directly on the targeted body system. No side effects have been identified in research with respect to tribulus usage. Many bodybuilders and strength athletes consume tribulus in a formulation known as a "stack," where it is believed that a number of supplements, taken together, will produce a beneficial effect where the sum is greater than its constituent parts. A well-regarded stack in the strength training community consisted of tribulus, DHEA (dehydroepiandosterone, a hormone-building raw material within the body), and androstenedione (or andro, a substance known as a prohormone, and one which will be converted into testosterone within the body, a muscle-building supplement). Andro was proven to cause significant side effects among its users, including cardiovascular problems, and it has somewhat fallen from favor in the strength training and fitness community.

Persons engaged in strength training who use tribulus are now more likely to stack tribulus with a mineral supplement known by the acronym ZMA, a compound that is commercially available in several formulations. The most popular ZMA mixture is generally constituted with zinc, magnesium, and vitamin B-6; zinc is a component of over 3,000 different proteins within the body, and magnesium is essential to both nervous system function and bone formation. The popularity of this tribulus stack is rooted in word-of-mouth endorsements from users than it is supported by hard science. There are few side effects that have been identified from the use of the combination of tribulus and ZMA.

SEE ALSO Dietary supplements; Ephedra; Herbs; Muscle mass and strength; Strength training.