Objective: The objective of this study was to evaluate the efficacy of Tribulus terrestris for the treatment of hypoactive sexual desire disorder in postmenopausal women and evaluate its effect on the serum levels of testosterone.
Methods: We performed a prospective randomized, double-blinded, placebo-controlled study, during 18 months. A total of 45 healthy sexually active postmenopausal women reporting diminished libido were selected to participate in the study and were randomly assigned to receive 750 mg/d of T terrestris or placebo for 120 days. Randomization was performed using sealed envelopes. All participants answered the Female Sexual Function Index and the Sexual Quotient-female version questionnaires and had their serum levels of prolactin, thyroid-stimulating hormone, total testosterone, and sex hormone-binding globulin measured.
Results: A total of 36 participants completed the study, because 3 from each group were excluded due to side effects and 3 dropped out due to personal reasons. FSFI questionnaire results demonstrated an improvement in all domains in both groups (P < 0.05) except for lubrication which was improved only in the study group. QS-F results showed a significant improvement in the domains of desire (P < 0.01), arousal/lubrication (P = 0.02), pain (P = 0.02), and anorgasmia (P < 0.01) in women who used T terrestris, whereas no improvement was observed in the placebo group (P > 0.05). Moreover, free and bioavailable testosterone levels showed a significant increase in the T terrestris group (P < 0.05).
Conclusions: Tribulus terrestris might be a safe alternative for the treatment of hypoactive sexual desire disorder in postmenopausal women, because it was effective in reducing symptoms with few side effects. Its probable mechanism of action involves an increase in the serum levels of free and bioavailable testosterone.