Evidence Review
Systematic Review: Testosterone and Erectile Dysfunction in Men (Vilar Neto et al., 2025)
A 2025 systematic review in Nutrients analyzed 10 clinical trials enrolling 483 men aged 16–70 with erectile dysfunction. Tribulus doses ranged from 400–750 mg/day over 1–3 months. [1]
On testosterone: eight of ten studies found no statistically significant change in serum testosterone. Two studies did show increases of approximately 60–70 ng/dL, but exclusively in men with baseline hypogonadism. The authors concluded there is "no robust evidence" for testosterone elevation in healthy men and that marketing claims remain "unsubstantiated" by the current clinical evidence base.
On erectile function: three of five studies assessing this outcome found significant improvement on validated scales (primarily the International Index of Erectile Function, IIEF). The overall assessment was "low level of evidence regarding effectiveness" — meaningful enough to keep investigating, but not yet at the level where strong recommendations can be made.
Safety across the included trials was generally favorable, with no significant difference in adverse events between treatment and placebo arms.
Randomized Controlled Trial: Male Sexual Dysfunction (Kamenov et al., 2017)
A well-designed double-blind RCT published in Maturitas enrolled 180 men aged 18–65 with mild to moderate erectile dysfunction, with or without hypoactive sexual desire disorder. [2] After 12 weeks, men receiving tribulus showed a mean improvement of 2.70 points on the IIEF score compared to placebo (p < 0.0001). This is a clinically modest but statistically robust difference. The treatment was well tolerated with no drug-related serious adverse events.
The authors propose that the benefit operates primarily through nitric oxide pathways rather than hormonal ones — meaning tribulus may improve erectile function through vascular rather than endocrine mechanisms.
Systematic Review: Female Sexual Dysfunction (Martimbianco et al., 2020)
Five RCTs with 279 female participants (premenopausal and postmenopausal) were analyzed in a 2020 systematic review in Revista Brasileira de Ginecologia e Obstetrícia. [3] Both premenopausal and postmenopausal women showed significant increases in standardized sexual function scores. Premenopausal women also showed a statistically significant increase in serum testosterone levels after three months.
The authors assigned a "very low certainty of evidence" rating, primarily due to small sample sizes and heterogeneous outcome measures. Adverse events were minimal across all included trials. The reviewers recommend shared decision-making between patients and clinicians given the early-stage nature of the evidence.
Placebo-Controlled Study: Late-Onset Hypogonadism (GamalEl Din et al., 2019)
A 2019 trial in Urologia specifically enrolled 70 aging men with testosterone in the low-normal range and existing erectile dysfunction. [4] After three months of tribulus supplementation, the treatment group showed significant increases in total testosterone (p < 0.001) and meaningful improvement on the Arabic Index of Erectile Function (baseline mean 10.7 rising to 16.1, p < 0.001). Lower urinary tract symptoms did not worsen.
Notably, this trial detected a small but statistically significant elevation in AST liver enzyme (26.5 to 27.8, p = 0.03) and PSA (1.4 to 1.7, p = 0.007). Neither value crossed into clinical concern in healthy subjects, but the PSA signal warrants caution in men with prostate risk factors.
Infertility Trial: No Benefit Detected (Roaiah et al., 2016)
A trial at Cairo University enrolled 30 men with idiopathic infertility and administered 750 mg/day of tribulus extract in divided doses for three months. [5] No statistically significant improvements were found in sperm concentration, motility, or morphology, and testosterone levels were unchanged. This null result is important context: tribulus does not appear to be an effective treatment for male infertility, which is a distinct clinical condition from erectile dysfunction.
Overall Evidence Assessment
The picture that emerges from current clinical evidence is specific: tribulus terrestris shows genuine promise for sexual dysfunction — modest erectile improvement in men and libido support in women — likely through nitric oxide and androgen-sensitizing mechanisms rather than direct testosterone production. Claims of meaningful testosterone elevation in healthy individuals are not well supported. Evidence quality across studies remains low to moderate, with small sample sizes and short durations as recurring limitations. For individuals with documented low-normal testosterone or mild sexual dysfunction, tribulus represents a reasonable low-risk option worth discussing with a healthcare provider.