Pro-sexual and androgen enhancing effects of Tribulus terrestris L.: Fact or Fiction

Ethno-pharmacological relevance: Historically, aphrodisiacs have had a reputation for making sex more achievable and satisfying. It has been long believed that Tribulus terrestris L. (TT), an annual plant of the family Zygophyllaceae, possesses aphrodisiac properties purportedly attributed to its ability to influence levels or mimic function of sex hormones. Due to this appealing beliefs, the popularity of medicinal products from TT is expanding at a remarkable pace among consumers who are attempting to enhance their sexual health. However, reliable scientific evidence supporting these purported bioactivities are scant and far from conclusive.

Aim of the review: To critically analyze and updated the evidence supporting a role for TT as an aphrodisiac and to reappraise the widely believed view of TT as an androgen enhancing botanical supplement.

Material and method: An extensive review of the literature was carried out based on systematic search of major scientific databases (PubMed, Elsevier, Springer Link, Google Scholar, Medline Plus, and Web of Science) for studies of phytochemical, pharmacological and traditional uses of TT published between 1968 and 2015. In addition, the reference lists of the available articles were reviewed and relevant studies including material in journals which are not indexed internationally were reviewed.

Results: Analysis of phytochemical and pharmacological studies in humans and animals revealed an important role for TT in treating erectile dysfunction and sexual desire problems; however, empirical evidence to support the hypothesis that this desirable effects are due to androgen enhancing properties of TT is, at best, inconclusive, and analysis of empirical evidence from a comprehensive review of available literature proved this hypothesis wrong. While the mechanisms underlying TT aphrodisiac activity remain largely unknown, there is emerging compelling evidence from experimental studies in animals for possible endothelium and nitric oxide-dependent mechanisms underlying TT aphrodisiac and pro-erectile activities.

Conclusion: It is becoming increasingly clear that the deep-seated traditional view of TT bioactivity focused exclusively on its androgen enhancing properties is outdated and incapable for accommodating the emerging evidence from recent clinical and experimental studies pointing toward new and, perhaps, more plausible modes of action. Novel paradigms guiding the development of new testable hypotheses for TT aphrodisiac properties are needed to stimulate further investigations into potential biological mechanisms in which many apparently conflicting observations can be reconciled.