Evidence explainerTongkat ali

Tongkat Ali Side Effects: Short Safety Data, a Drug Interaction and Tainted Products

Short trials reported no severe adverse events, but tongkat ali cut propranolol absorption, and FDA warns that many sexual-enhancement and male-energy products hide drug ingredients.

By Kymata Health editorial teamPublished October 9, 2026Last reviewed October 9, 2026

Medical review pending. Written by our editorial team from the studies cited below; a credentialed clinician has not reviewed it yet. Educational only, not medical advice.

Key takeaways

  • A 4-week trial of 200 mg/day, with 81 people analysed, reported no severe adverse events [1].
  • Taken with propranolol, 200 mg of a water extract lowered the drug's bioavailability by 29% and its peak level by 42% in 14 healthy young men [2].
  • FDA says many products sold for sexual enhancement, male energy or stamina are likely to be contaminated with dangerous hidden ingredients [3].
  • In a 2-week trial in young men, estradiol rose along with testosterone [4].
  • Our sources include no long-term safety studies.

The evidence, graded

Pulled from our monograph evidence tables. Grades follow our evidence-grading policy.

  • Grade CImprovedImmune vigor scores and T-cell countsTongkat ali · RCT · n=81 · 2016 · PMID 26816234Immune vigor score, immunological grade and total, naive and CD4+ T-cell counts were higher than placebo at week 4. No severe adverse events.
  • Grade DImprovedTotal and free testosteroneTongkat ali · RCT · n=32 · 2021 · PMID 33559971Total testosterone, free testosterone and estradiol rose more than with placebo; luteinising hormone, FSH and SHBG did not change.

What trials report

In a 4-week placebo-controlled trial of 200 mg/day of a standardised root water extract, 40 people on tongkat ali and 41 on placebo were analysed, and no severe adverse events were observed [1].

In a 2-week trial of 600 mg/day in 32 healthy young men, estradiol rose along with total and free testosterone, while luteinising hormone, follicle-stimulating hormone and SHBG did not change [4]. Both trials were short, so they say little about months or years of use [1][4].

The propranolol interaction

In a crossover study of 14 healthy young men, 200 mg of a water-based extract taken with propranolol lowered the drug's bioavailability (AUC) by 29% and its peak level by 42%, and delayed its peak by almost 86% [2]. Its elimination half-life was not significantly affected, pointing to reduced absorption [2].

The authors note that men taking propranolol for high blood pressure may also use the herb, and advise caution when the two are taken together [2].

Hidden ingredients in sexual-enhancement products

FDA says many products sold for sexual enhancement, including male enhancement supplements and male energy or stamina pills, are likely to be contaminated with dangerous hidden ingredients [3]. These products are sometimes falsely advertised as dietary supplements or all-natural, and can lead to severe health issues and hospitalization [3].

FDA adds that its notification list covers only a small fraction of contaminated products, and that a product missing from the list is not necessarily safe [3].

Who should be careful

People taking propranolol should check with a pharmacist first, given the absorption study [2]. Our sources do not cover pregnancy or breastfeeding, so anyone pregnant, breastfeeding or managing a chronic condition should talk to a clinician before adding tongkat ali.

For what the trials measured, read does tongkat ali work.

Quick answers

Does tongkat ali cause hair loss?

None of the trials in our sources reported hair loss as an outcome or a side effect.

Does tongkat ali affect the liver or kidneys?

Our sources include no liver or kidney data for tongkat ali; the 4-week trial reported no severe adverse events [1].

Can tongkat ali be taken with heart medicines?

It lowered propranolol's bioavailability by 29% in one study, so anyone on prescription medicines should check with a pharmacist first [2].

Keep reading

Full monographs

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References

  1. [1]Immunomodulation in Middle-Aged Humans Via the Ingestion of Physta Standardized Root Water Extract of Eurycoma longifolia Jack: A Randomized, Double-Blind, Placebo-Controlled, Parallel Study. Phytother Res, 2016. PMID 26816234
  2. [2]Modification of propranolol's bioavailability by Eurycoma longifolia water-based extract. J Clin Pharm Ther, 2010. PMID 21054461
  3. [3]Sexual Enhancement and Energy Product Notifications (content current as of 09/25/2026). U.S. Food and Drug Administration, 2026.
  4. [4]The effect of Eurycoma Longifolia on the regulation of reproductive hormones in young males. Andrologia, 2021. PMID 33559971

Tongkat ali and other dietary supplements are not intended to diagnose, treat, cure or prevent any disease, and these statements have not been evaluated by the FDA. Talk to your clinician or pharmacist before starting a supplement, especially if you take prescription medicines. This page has no product or affiliate links.

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