Tongkat ali, Eurycoma longifolia
Also called: longjack, Eurycoma longifolia, pasak bumi, 100:1 extract, eurycomanone.
A Southeast Asian root sold for testosterone: small trials, one commercial extract everywhere, documented contamination and safety not established in Europe.
What it is
Tongkat ali is a Southeast Asian shrub whose root contains quassinoids, including eurycomanone, used as a standardization marker. LiverTox puts the traditional dose at 100 to 400 mg per day, whereas products for bodybuilders contain 1,000 to 1,600 mg. People buy it for testosterone, libido and muscle mass.
What the label does not say
- The testosterone trials are small: the 2022 meta-analysis brings together 5 randomized trials and 232 men, at 100 to 600 mg per day for 3 days to 6 months, with a significant rise mostly in hypogonadal men, 87% heterogeneity and the same commercial extract in seven of nine studies. In healthy men with normal levels, the rise did not reach significance.
- Contamination: of 100 tongkat ali products analyzed in Malaysia, 36 exceeded the 0.5 ppm mercury limit (0.52 to 5.30 ppm), including registered products, with variability from one lot to another.
- In 2021, the EFSA concluded that the safety of the root extract, proposed at 200 mg per day, was not established, because of a genotoxic signal (positive comet assay in the stomach and duodenum at the highest dose tested). In Canada, licensed products display "helps to promote testosterone production in men", with a contraindication in case of prostate cancer, diabetes, heart, kidney or liver disease.
- LiverTox classes tongkat ali in category D (a possible rare cause of liver injury): isolated cases, mostly in bodybuilders, with undeclared use of anabolic steroids that muddies the reading.
The forms on the shelf
- Standardized aqueous extract (0.8 to 1.5% eurycomanone, 40 to 65% glycosaponins according to the EFSA): this is the patented commercial extract used in seven of the nine studies identified by the 2022 meta-analysis.
- "100:1" or "200:1" extracts: the ratio says how many grams of root went into making one gram of extract, not what the extract contains. Without a eurycomanone or glycosaponin content, the number compares nothing.
- Raw root powder: without standardization.
Published reference values
- No recommended intake. Trial doses: 100 to 600 mg of standardized extract per day; traditional dose 100 to 400 mg; dose proposed in Europe 200 mg.
- Effects reported in the trials: digestive symptoms and itching in one trial, few effects elsewhere; allergic reactions mentioned on Canadian licences.
- Canadian licences require advice in case of benign prostatic hyperplasia, a weakened immune system, use of blood sugar-lowering drugs or propranolol.
When
The trials gave the extract daily for weeks or months; LiverTox notes that the effect on testosterone takes several weeks to appear. There are no data on the timing of the dose.
Keep apart from
- Blood sugar-lowering drugs and propranolol: medical advice required on Canadian licences, with no documented spacing by the hour.
To mention to a professional
- Prostate cancer or enlargement, diabetes, heart, kidney or liver disease, immunosuppression, use of anabolic steroids, pregnancy and breastfeeding (products intended for men 18 and over): check with a health care professional.
What it is sold for, and what the data show
Tongkat ali is sold for testosterone and muscle mass. The data come from five small trials, most with a patented extract, with an effect mostly in men with low levels; nothing shows a gain in mass in healthy men. On the other side: documented mercury contamination, safety not established by the EFSA and isolated liver cases.
Sources
- LiverTox (NIH), Tongkat Ali
- Leisegang et al., Eurycoma longifolia (Jack) Improves Serum Total Testosterone in Men: A Systematic Review and Meta-Analysis of Clinical Trials, Medicina, 2022
- EFSA, Safety of Eurycoma longifolia (Tongkat Ali) root extract as a novel food, EFSA Journal, 2021
- Ang, Lee and Cheang, Determination of Mercury by Cold Vapor Atomic Absorption Spectrophotometer in Tongkat Ali Preparations Obtained in Malaysia, International Journal of Toxicology, 2004
- Health Canada, Licensed Natural Health Products Database, record for a Eurycoma longifolia product (claim, warnings and contraindications)
Educational information, drawn from the sources above. It does not replace the advice of a health professional, who remains the reference for your situation, your medications, pregnancy or breastfeeding.