Tongkat Ali Safety: Side Effects, Liver Questions and Who Should Not Take It

What LiverTox actually says about tongkat ali and the liver

LiverTox is the National Institutes of Health's clinical reference on drug- and herb-induced liver injury. It assigns tongkat ali a likelihood score of D — a possible but rare cause of clinically apparent liver injury. On the trial data it is direct: in small, short-term clinical studies of different preparations and concentrations, adverse effects were usually described as uncommon, unrelated to therapy and minimal, with no changes in serum ALT, AST, GGT or bilirubin.

Then come the two caveats no vendor page reproduces. First: the effects of long-term use and of higher doses have not been assessed in humans. Second: there is no standardisation of purity and concentration across the extracts on the market. Short-term use of a studied extract looks clean; everything outside that box is untested rather than proven safe.

The one published case report, and what it does not prove

A 2024 case report in Cureus describes a 47-year-old man who developed jaundice about a week after starting tongkat ali for bodybuilding, with enzymes peaking at ALT 876 U/L, AST 445 U/L, ALP 238 U/L and total bilirubin 14.3 mg/dL. He recovered after stopping. Read it as what it is: one patient, an unverified product and dose, with the authors noting the mechanism is not understood and this was the first reported case of its kind. LiverTox adds that reported cases have largely occurred in young male bodybuilders, where unacknowledged anabolic steroid use weakens the attribution to Eurycoma longifolia. A case report cannot establish causation. It can keep the question open.

The safety evidence, source by source

Every source we could verify to primary, and how much weight each carries. The picture changes sharply depending on whether you are reading a trial, a regulator or a case report.

Source	What it is	What it found	Strength
NIH LiverTox, "Tongkat Ali" (NBK609015)	NIH reference on herb-induced liver injury	Likelihood score D. Adverse effects uncommon and minimal in short-term studies, no changes in ALT, AST, GGT or bilirubin. Long-term use and higher doses not assessed in humans; no standardisation of purity across extracts.	Highest — expert synthesis
EFSA NDA Panel, EFSA Journal 2021;19(12):e06937	EU safety assessment of a standardised water root extract at up to 200 mg/day	In vitro chromosome aberration positive; in vivo comet assay in rats positive in stomach and duodenum at 2,000 mg/kg body weight/day, no effect in liver. Conclusion: "the safety of the NF has not been established under any condition of use."	High regulatory weight — animal and in vitro, not human
Chinnappan SM et al., Food Nutr Res 2021;65	RCT; 105 men aged 50–70, baseline testosterone under 300 ng/dL; Physta 100 or 200 mg vs placebo; 12 weeks	Eight adverse events, none judged related; mild GI complaints in three subjects per active arm; no significant change in SGOT or SGPT.	Good — short, screened population
George A et al., Food Nutr Res 2018;62	RCT; 86 completers aged 25–65; 50 mg Physta plus multivitamins; 24 weeks	Thirteen adverse events (six placebo, seven active); no significant change in vital signs or metabolic panel; safe and well tolerated.	Good — longest RCT located; low dose, combination product
Talbott SM et al., J Int Soc Sports Nutr 2013;10:28 (PMID 23705671)	RCT; 63 moderately stressed adults; 200 mg/day water extract; 4 weeks	No adverse safety signal reported, but outcomes were cortisol, testosterone and mood — tolerability evidence only.	Moderate — very short, small
Kaliounji et al., Cureus 2024 (PMC11032125)	Single case report	47-year-old man, about one week of use; peak ALT 876 U/L, AST 445 U/L, ALP 238 U/L, bilirubin 14.3 mg/dL; recovered after stopping.	Low for causation — n = 1, product unverified
Operation Supplement Safety (US Dept of Defense)	Government supplement-safety guidance	Generally safe in small-dose short-term oral studies; side effects gastrointestinal and itching; products reported contaminated with heavy metals such as lead and mercury, or adulterated with sildenafil.	High for practical risk — product quality, not pharmacology

Reported side effects at conventional doses

Pooling what the trials and the government guidance actually recorded, the complaints at conventional doses are mild and mostly digestive: constipation, dyspepsia and abdominal discomfort in the trials, plus gastrointestinal upset and itching in the OPSS summary. Insomnia and restlessness are widely claimed online; we could not trace either to a controlled trial, so treat them as anecdote. If you experience anything more than mild and transient, stop and speak to a clinician.

The EFSA 2021 opinion, stated plainly

This is the finding vendor pages omit or soften, so here it is without spin. In 2021 the European Food Safety Authority's Panel on Nutrition, Novel Foods and Food Allergens assessed a standardised Eurycoma longifolia water root extract submitted as a novel food at up to 200 mg per day — roughly the trial dose. The in vitro chromosome aberration test came back positive, indicating clastogenic potential. The follow-up in vivo alkaline comet assay in rats showed significant DNA strand breaks in the stomach and duodenum at the highest dose tested, 2,000 mg per kilogram of body weight per day, with histopathology suggesting genotoxicity rather than simple cell damage. There was no effect in the liver. The Panel concluded that the safety of the novel food had not been established under any condition of use.

Three things follow. The dose that produced the signal is enormous relative to human intake. The finding is in animals and cell systems, not people. And a regulator declining to approve something is not a regulator finding it harmful — EFSA's position is that the question was not answered, which is why the ingredient is not authorised as a novel food in the EU. The honest reading is caution, not alarm, and certainly not the silence you get from pages selling it.

Who should not take tongkat ali

Drawn from what the trials screened out, what LiverTox flags and what the interaction references say. Not exhaustive, and not a substitute for asking your own doctor.

• Anyone under 18. No trial has enrolled minors.
• Anyone taking prescription medication. Interactions are under-studied for this plant, and "no reported interaction" is a gap in the literature, not a clearance.
• Anyone treated for a prostate or hormonal condition. Ingredients marketed for hormonal pathways do not belong in a treatment plan without the prescriber's knowledge.
• Anyone scheduled for surgery. Stop well in advance and tell the surgical team.
• Anyone with existing liver disease. People with liver conditions were screened out of the trials, so there is no human safety data covering them — not reassuring data, none at all.
• Anyone on warfarin, other anticoagulants or antiplatelet drugs, if the formula also contains saw palmetto, as multi-botanical male-vitality products including Primordial Vigor X commonly do. Memorial Sloan Kettering's saw palmetto monograph advises against use with warfarin or other blood thinners and with antiplatelets such as clopidogrel; the Merck Manual consumer entry states saw palmetto may interact with warfarin, anticoagulants and antiplatelet medications and result in bleeding.
• Women, and anyone pregnant or breastfeeding. These products are formulated for adult men, and the Merck Manual advises that women who are pregnant or may become pregnant should not take saw palmetto.

The risk that has nothing to do with the herb

Most safety writing on this topic argues about the botanical. The more actionable risk is the product. OPSS — the US Department of Defense's supplement safety programme — reports that tongkat ali products have been found contaminated with heavy metals such as lead and mercury, or adulterated with sildenafil, a prescription medicine that has no business in a supplement and can be dangerous for anyone taking nitrates.

That is a property of an unregulated supply chain, not of Eurycoma longifolia, and it is why certification language deserves scrutiny. "GMP certified" and "FDA registered" describe the facility, not a batch tested for identity, potency, heavy metals or adulterants. The seals that speak to contents are third-party programmes such as USP Verified, NSF Certified for Sport and Informed Sport — and even then the certifier's lot database is the proof, not the logo.

Applied here: Primordial Vigor X publishes an 870 mg total for a three-botanical blend of Tribulus terrestris, tongkat ali and saw palmetto berry, but no verified per-ingredient breakdown or standardisation. You cannot map its tongkat ali content onto any trial dose above, and neither can we — which is why our Primordial Vigor X review tells you to read the Supplement Facts panel rather than take a number on trust. For what the studies measured, see our evidence review of tongkat ali and Tribulus.

What the evidence does not show

Not that tongkat ali is safe long term. The longest randomised trial we located ran 24 weeks, at 50 mg a day, in a combination product. "No signal in six months" is not "safe for five years".

Not that higher doses are safe. Trials clustered at 50–300 mg a day. Products sold at 600 mg or 1,000 mg sit outside the tested range, and LiverTox says higher doses have not been assessed in humans.

Not that the genotoxicity question is closed. EFSA's comet-assay finding was in rats at a dose far above human intake, with no human equivalent study.

Not that the case report was caused by tongkat ali. One patient, one unverified product, and documented confounding by anabolic steroid use in that population.

And none of this is a treatment claim. Tongkat ali is a dietary supplement, not intended to diagnose, treat, cure or prevent any disease. Persistent fatigue, low mood, low libido or urinary symptoms deserve a clinician's assessment rather than a capsule. Whether to cycle it is a separate question — covered in should you cycle tongkat ali.

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