Tribulus Terrestris

Proposed mechanisms. Tribulus contains steroidal saponins (especially protodioscin) that have been hypothesized to influence androgen pathways and nitric-oxide signaling. Lab and translational summaries note possible effects on DHEA, NO-mediated vasodilation, and other pathways related to sexual function—but the testosterone link remains uncertain. Memorial Sloan Kettering Cancer Center

What modern reviews conclude. A 2025 PRISMA systematic review of clinical trials (10 studies, n=483) found no robust evidence that tribulus raises testosterone in men overall. Most trials showed no significant change in androgen profile; two small, lower-quality trials in men with documented hypogonadism reported modest increases (~60–70 ng/dL)—a change often too small to resolve symptomatic hypogonadism by itself. The same review found some signal for improved erectile function in mild–moderate ED, but emphasized low study quality. MDPI

Big picture. If your goal is treating low testosterone, tribulus is not a proven testosterone booster. At best, a minority of small studies in men with confirmed low T have shown modest increases; most studies (especially in eugonadal men) show no T increase. MDPI

First, confirm true hypogonadism. Guidelines advise diagnosing low T with two separate early-morning total testosterone tests (ideally before 11 a.m.), plus evaluation of LH/FSH to define primary vs secondary hypogonadism. If low/borderline, repeat and assess SHBG, prolactin, and causes. Don’t start any therapy targeted at “low T” without this step. Chromosome Variations Association

If, after proper diagnosis and clinician discussion, you still want to trial tribulus, the most common evidence-based pattern is:

• Extract & standardization: Products standardized to ≈45% saponins (protodioscin-rich) were used in positive RCTs. Look for third-party tested products (e.g., USP/NSF) and standardized saponin content to approximate study material. MM Encapsulation
• Dose used in RCTs with hypogonadal men: 250 mg capsule, three times daily (TID) of a 45% saponin extract, for 3 months (total 750 mg/day). MM Encapsulation
• Alternate trial doses: Reviews summarizing trials report 400–750 mg/day for 1–3 months. MDPI
• With food? Many clinicians advise taking with meals to reduce GI upset (reflecting general practice with saponin-rich botanicals); trials did not consistently specify timing. (General practice note—evidence limited.)

Monitoring if you trial it (prudent approach):

1. Baseline labs: morning total T (± free T), LH/FSH, ALT/AST, PSA (if appropriate for age/risk). NICE
2. Duration: 8–12 weeks is what the RCTs used; reassess by week 12. MM Encapsulation
3. Re-check: T panel, symptoms, liver enzymes, and PSA (one RCT noted small but statistically significant PSA and AST increases with tribulus). Discontinue if no meaningful clinical response or if labs/symptoms worsen. MM Encapsulation

Important: For men with confirmed hypogonadism who remain symptomatic, testosterone-replacement therapy (TRT) has far stronger evidence; consider discussing guideline-based options with your clinician. Chromosome Variations Association

Systematic reviews / overviews

• 2025 Nutrients PRISMA review: “No robust evidence for increasing testosterone levels; modest increases only in small, lower-quality hypogonadal trials.” Also notes mixed but sometimes positive effects on ED symptoms at 400–750 mg/day for 1–3 months. MDPI
• 2022 systematic review (single-herb effects on testosterone in men): Broad review of herbal RCTs found limited and inconsistent effects of tribulus on serum testosterone. ScienceDirect
• 2025 IJIR meta-analysis (ED focus): Found benefit signals for erectile dysfunction, not designed to prove testosterone increases. Nature

Randomized/controlled trials in hypogonadal or low-T men

• GamalEl Din et al., 2018 (Urologia Journal): 70 men (ED + partial androgen deficiency). Tribulus 250 mg TID x 3 months (45% saponins) vs placebo → ↑ total T and IIEF-5; small ↑ AST and PSA; no LUTS worsening. Single-blind; methodologic limits. PDF available. MM Encapsulation
• Roaiah et al., 2016 (pilot): Aging men with partial androgen deficiency showed intra-group T increases and improved erectile function; small, pilot, lower quality. gmouton.com

Trials showing no T increase (context)

• The majority of trials in eugonadal men (athletes/healthy volunteers) did not raise testosterone, reinforcing that tribulus is not a general T-booster. Summarized in the 2025 review. MDPI