Tongkat Ali: What the Research Says About Testosterone and Stress

Tongkat Ali — the root extract of Eurycoma longifolia, a rainforest tree native to Malaysia and Indonesia — has been used in traditional medicine for centuries as a remedy for fatigue and low libido. Over the past two decades it has moved into clinical research, and the findings are more nuanced than most supplement marketing suggests. The evidence for its effects on testosterone and cortisol is real but context-dependent, and the mechanisms involve more than simple hormone boosting.

What Tongkat Ali Actually Is

The active compounds in Tongkat Ali are quassinoids — primarily eurycomanone — along with eurypeptides and glycosaponins. These compounds appear to work through two principal pathways: inhibiting the conversion of testosterone to estrogen by suppressing aromatase activity, and reducing the binding of testosterone to sex hormone-binding globulin (SHBG), which releases more free testosterone into circulation. Neither pathway involves stimulating the hypothalamic-pituitary-gonadal axis directly, which distinguishes it from synthetic androgens and anabolic steroids. The mechanism is modulatory rather than override.

The Testosterone Evidence

The most cited human trial is a 2012 study published in Phytotherapy Research, in which 76 men with late-onset hypogonadism received 200mg of a standardized water-soluble Tongkat Ali extract daily for one month. At baseline, 35.5 percent of subjects had testosterone levels classified as normal. After four weeks of supplementation, that figure rose to 90.8 percent. Serum testosterone concentrations increased by an average of 46 percent across the cohort. These were men with clinically low testosterone — not healthy young men with already-normal levels.

A 2014 pilot study in the Journal of the International Society of Sports Nutrition examined 13 physically active male subjects given 400mg of Tongkat Ali extract daily for five weeks alongside resistance training. Lean body mass increased, fat mass decreased, and arm muscle circumference improved compared to placebo. Importantly, the effect size was modest and the sample small — a recurring limitation in this literature.

For men with normal baseline testosterone, the evidence is considerably weaker. A 2013 study in Andrologia found no significant change in testosterone in healthy men given 400mg daily for two months. The pattern across the literature suggests Tongkat Ali is more effective at restoring testosterone toward a normal range than at elevating it significantly above normal baseline levels.

The Cortisol Angle

One of the more compelling findings involves the cortisol-to-testosterone ratio — a biomarker of physiological stress load used in sports medicine. A 2013 study published in the Journal of the International Society of Sports Nutrition randomized moderately stressed adults to 200mg of Tongkat Ali extract or placebo for four weeks. The Tongkat Ali group showed a 16 percent reduction in salivary cortisol, a 37 percent increase in serum testosterone, and significant improvements on a mood state questionnaire measuring tension, anger, and confusion. The mechanism proposed is that eurycomanone inhibits cortisol synthesis in the adrenal cortex during periods of chronic stress.

This matters because cortisol and testosterone are inversely related — chronic cortisol elevation actively suppresses testosterone production at the hypothalamic and gonadal level. If Tongkat Ali lowers cortisol, it may partially restore testosterone through reducing that suppression, rather than acting directly on androgen biosynthesis. The distinction changes how you think about who is likely to benefit.

Athletic Performance

The performance data is limited but directionally interesting. A double-blind crossover study in the British Journal of Sports Medicine (2003) found that recreational athletes given Tongkat Ali for five weeks showed significantly greater improvements in lean body mass, 1-rep max on leg press, and arm circumference compared to placebo, with concurrent changes in testosterone and cortisol. Cycling studies have shown modest improvements in aerobic output at the same doses, though the evidence here is less consistent.

Momentous Tongkat Ali — the extract used in the protocols popularized by Andrew Huberman — uses a standardized water-soluble extract at 400mg per serving with Informed Sport certification, which third-party tests for banned substance contamination. This matters especially for competitive athletes.

Dosing and Extract Standardization

The most studied dose is 200–400mg daily of a standardized water-soluble extract. The key variable is extraction ratio and eurycomanone content — a 200:1 extract ratio does not automatically mean higher potency than a 100:1 ratio if the eurycomanone percentage is not standardized. Look for extracts that specify eurycomanone content (typically 0.8–2%) rather than relying on extraction ratio alone.

Cycling is commonly recommended in traditional use (e.g., five days on, two days off) but lacks clinical trial support. Human studies up to 12 weeks have not reported significant adverse events at doses up to 400mg daily. Liver function tests have not shown abnormalities in the clinical literature at these doses, though case reports of hepatotoxicity exist at much higher doses — a caution against megadosing.

Synergy With Shilajit

Shilajit — a mineral resin from Himalayan rock — is often paired with Tongkat Ali in modern stacks. A 2016 study in Andrologia found that PrimaVie shilajit extract at 250mg twice daily significantly increased total testosterone, free testosterone, and DHEA in healthy male volunteers aged 45–55 over 90 days. The proposed mechanism involves fulvic acid improving mitochondrial electron transport and nutrient delivery to Leydig cells — the testosterone-producing cells in the testes. The two compounds address different aspects of the same system, which is why they're frequently combined. LIVS Pure Himalayan Shilajit provides 50% standardized fulvic acid — the active fraction — at 1000mg per serving.

Who Is Most Likely to Benefit

The clearest case for Tongkat Ali is men over 40 experiencing age-related testosterone decline, men under significant chronic stress with measurably elevated cortisol, or those with clinically confirmed low testosterone who are not yet candidates for hormone replacement therapy. For young men with already-normal testosterone levels, the expected effect on absolute testosterone numbers is small, though the cortisol-modulating effect may still be meaningful in the context of training recovery and mood.

Women have been included in some trials, with positive effects on mood and tension reported, though testosterone-specific outcomes are less relevant. The cortisol and stress-buffer effects appear to apply regardless of sex.

If you're evaluating it, Double Wood Tongkat Ali 200:1 provides 1000mg per serving with third-party testing — a common starting dose that maps to the 200mg eurycomanone-standardized extract doses studied in the clinical literature when the extract contains approximately 0.8% eurycomanone.