Tribulus terrestris (puncture vine)

Tribulus is sold as «natural Viagra» for erectile dysfunction. Evidence base is minimal: small Bulgarian and Indian RCTs showed heterogeneous IIEF scale results; no large international RCTs. AUA 2018 lists PDE-5 inhibitors (sildenafil, tadalafil, vardenafil, avanafil) first-line for ED; tribulus is not mentioned. If tribulus was recommended for ED instead of workup (testosterone, HbA1c, lipid panel, TSH) and standard therapy, consider seeking a second opinion from a urologist.

Tribulus terrestris is the top-selling «natural testosterone booster» in sport and biohacking segments, promising testosterone, muscle mass and libido increase. Systematic reviews and RCTs refute the effect: Neychev 2008 (J Ethnopharmacol) in 21 healthy young men showed no changes in total and free testosterone, LH or FSH with tribulus vs placebo. Pokrywka 2014 systematic review confirmed no hormonal effect. Endocrine Society 2018 in confirmed hypogonadism (total testosterone <300 ng/dL on two morning samples + symptoms) recommends testosterone replacement therapy under endocrinology supervision. If tribulus was recommended for «low testosterone» without proper workup, consider seeking a second opinion from an endocrinologist.

Tribulus is sold in pre-workout formulas and «testosterone boosters» as a muscle gain product. No evidence base: no quality RCTs with lean body mass and strength endpoints. For muscle gain IOC 2018 and ISSN 2015 list creatine monohydrate (3-5 g/day), adequate protein (1.6-2.2 g/kg), progressive overload and caloric surplus; tribulus is not in the IOC-approved sports supplement list.