Tongkat ali (Eurycoma longifolia)

Tongkat ali is actively marketed as a «natural aphrodisiac» and a «safe alternative to Viagra». No evidence base supports these claims: RCTs are small, some are manufacturer-sponsored, and placebo-controlled data on erectile function (IIEF score) are weak. Erectile dysfunction requires cardiovascular and endocrine workup: 50-60% of cases in men over 40 relate to atherosclerosis, diabetes or hypogonadism, and these diagnoses need targeted treatment. IMPORTANT: in 2016-2019 the FDA recalled tongkat ali products for adulteration with undeclared sildenafil or tadalafil. This means some users of a «natural» supplement actually receive a PDE-5 inhibitor in an unknown dose – dangerous with nitrates (severe hypotension risk), cardiovascular disease and alpha-blocker interactions. Endocrine Society 2018 and AUA recommend, for erectile dysfunction, PDE-5 inhibitors (sildenafil, tadalafil, vardenafil) at known doses with cardiovascular monitoring. If erectile dysfunction is being treated with tongkat ali, seek a second opinion from a urologist or endocrinologist. The risk of heavy-metal contamination and adulteration is high – choose certified manufacturers.

Tongkat ali is an over-the-counter supplement actively marketed as a «natural testosterone booster». The Tambi RCT (Andrologia 2012) in 76 men with late-onset hypogonadism used the standardised water-soluble Physta extract 200 mg/day for one month: total testosterone rose from 5.7 to 8.7 nmol/L (normal >12) and Ageing Males' Symptoms scores improved. The study was sponsored by the manufacturer of Physta and lacked placebo control. Leisegang's systematic review (Andrologia 2022) pooled 11 RCTs: half showed a modest testosterone rise, half did not; evidence quality is limited by small samples (20-100 people), short duration (4-12 weeks) and sponsorship. EFSA in 2021 did not approve the novel-food application. The Endocrine Society Guideline 2018 recommends, in confirmed hypogonadism (total testosterone <12 nmol/L on two morning measurements with symptoms), testosterone replacement therapy by gel, injection or subcutaneous implant with monitoring of PSA, haematocrit and lipids; supplements do not substitute. IMPORTANT: in 2016-2019 the FDA recalled tongkat ali products for lead contamination and adulteration with sildenafil or tadalafil. If tongkat ali is being considered, discuss with an endocrinologist, choose certified manufacturers (USP, NSF, GMP) and get tested – if testosterone is low, replacement therapy is more effective than a supplement.

Tongkat ali is marketed as an «adaptogen for athletic endurance and anabolism». The Talbott RCT (J Int Soc Sports Nutr 2013) in 63 moderately stressed adults used Physta 200 mg/day for 4 weeks: salivary cortisol dropped 16%, testosterone rose 37% and questionnaire-based stress decreased. The sample is small, the duration short and the study sponsored by Biotropics Malaysia. Leisegang's systematic review 2022 found heterogeneity and low methodological quality in sports-related RCTs. No large independent RCTs on endurance measures (VO2max, time to exhaustion), strength (1RM) or muscle mass (DEXA) in trained athletes exist. EFSA did not approve the 2021 novel-food application. WADA does not list tongkat ali as prohibited, but adulterated batches may contain banned substances (anabolic steroids have been detected in tongkat ali products in Malaysian and Taiwanese studies). If tongkat ali is being considered as a «sports booster», discuss with a sports medicine physician – efficacy is unproven and contamination risk is high. For competing athletes choose products with Informed-Sport or NSF Certified for Sport certification.