Effects of Tribulus (Tribulus terrestris L.) Supplementation on Erectile Dysfunction and Testosterone Levels in Men-A...

Background: Tribulus terrestris L. Zygophyllaceae (TT) is a plant that has been claimed to increase testosterone levels and improve sexual function, particularly erectile dysfunction, with potential benefits for male sexual health. Purpose: This systematic review aimed to evaluate the effectiveness of TT supplementation in improving sexual function and serum testosterone levels in men. Methods: We conducted a systematic review adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. After searching the literature (n = 162), 52 studies were selected for full-text reading, and 10 studies were eligible for this review, comprising 9 clinical trials and 1 quasi-experimental study (a study without a control). The Jadad score revealed low methodological quality for 50% of the studies. Results: The studies involved 15 to 172 participants (total = 483) aged between 16 and 70 years with different health conditions: healthy men (n = 5), oligozoospermia (n = 1), erectile dysfunction (n = 1), erectile dysfunction associated with hypogonadism (n = 2), and unexplained infertility (n = 1). TT supplementation at doses of 400 to 750 mg/d for 1 to 3 months improved erectile dysfunction in 3 of the 5 studies that assessed this parameter. Eight out of ten studies did not report significant changes in androgen profile following TT supplementation, but the subjects in the neutral studies did not have low androgen levels at baseline. Therefore, only 2 studies showed significant intra-group increase in total testosterone levels, which had low clinical magnitude (60-70 ng/dL) and involved subjects with hypogonadism. Conclusions: TT supplementation has a low level of evidence regarding its effectiveness in improving erectile function in men with erectile dysfunction, and no robust evidence was found for increasing testosterone levels.