200–400 mg/day of standardized extract.
Small increases in testosterone and improved libido, especially when starting from low levels.
View the study (meta-analysis) →⏱ 3 min read
Tongkat ali, also known as Eurycoma longifolia or pasak bumi, is a Southeast Asian shrub whose root is used in traditional Malaysian, Indonesian, and Thai medicine as a tonic for male libido, energy, and recovery after illness or convalescence; the active compounds identified are quassinoids (especially eurycomanone), saponins, and alkaloids with documented activity on the hypothalamic-pituitary-gonadal axis, stress modulation, and mild anabolic effects.
Unlike pharmacological pseudo-androgens or exogenous testosterone therapies, tongkat ali does not introduce hormones into the body but appears to modulate endogenous production, possibly by displacing testosterone bound to sex hormone-binding globulin (SHBG) and thereby increasing the biologically active free fraction; this mechanism, together with a relatively good safety profile with short- to medium-term use, has positioned tongkat ali as a frequent option in formulations for men with symptoms suggestive of borderline low androgen levels.
The strongest evidence for tongkat ali is a modest increase in total and free testosterone in men with hypogonadal symptoms or low baseline testosterone: several randomized trials have shown significant increases in testosterone, reductions in cortisol, and subjective improvements in libido, energy, and well-being at doses of 200-400 milligrams per day of standardized extract for 4-12 weeks.
A randomized trial published in 2013 with 76 older men with subclinical hypogonadism showed that 200 mg/day of standardized extract (Physta) for 1 month significantly increased testosterone and improved male quality-of-life scales (AMS); these effects are modest compared with exogenous testosterone replacement therapy, but they may be useful for men with borderline values who prefer nonpharmacological interventions.
In people with moderate chronic stress, several trials have shown significant reductions in salivary cortisol, increases in testosterone, and improvements in subjective well-being scales at doses of 200 milligrams per day for 4 weeks, an indication that combines adaptogenic modulation with the mild anabolic effect characteristic of this plant.
Beyond the increase in testosterone, several studies have documented improvements in sexual function parameters (desire, erection, satisfaction) in adult men with mild to moderate sexual dysfunction, a traditional indication with some modern clinical support, although the methodological heterogeneity of the studies limits the strength of the conclusions.
Several small trials have shown improvements in sperm parameters (concentration, motility, morphology) in men with idiopathic infertility with supplementation for 3-9 months, an indication consistent with the hormonal and antioxidant profile of the plant.
The doses studied range from 200 to 400 milligrams per day of standardized extract (ideally with a declared eurycomanone content of around 1-2 percent), divided into one or two doses with or without food; the effects on testosterone and well-being appear gradually, typically from the third or fourth week, and require maintaining use for at least 8-12 weeks for a full evaluation.
Generally well tolerated at moderate doses; the most frequent adverse effects are insomnia (especially if taken late, which is why morning use is recommended), irritability, and occasionally headache or palpitations in sensitive people; people with hormone-dependent cancers should avoid it because of the increase in testosterone; those taking hormone replacement therapy, anticoagulants, or antihypertensives should consult a clinician first; in pregnancy and breastfeeding the data are limited, although the indication is clearly male; it is not recommended for people under 18; traditional non-standardized preparations may be contaminated with heavy metals, so it is advisable to choose products with certified purity testing.
Information, not medical advice. Scientific evidence reflects the quality of the studies.