Tongkat ali side effects: banned in the Netherlands, and why

The most important of all tongkat ali side effects is not a side effect but a ban. Tongkat ali is not admitted in the EU. The NVWA, the Dutch food authority, still found it at 10 companies in 2024, in 11 products. EFSA concluded that the substance is genotoxic: it can damage the genetic material in a cell.

What strikes me as a training partner? This appears on exactly one of the pages above this one. And then in a single sentence. The rest explain where you can order it.

I will explain why it is banned and what the trials did measure. And what you can check in your blood if you have already used it.

What is tongkat ali?

Tongkat ali (Eurycoma longifolia) is a tree from Malaysia and Indonesia. An extract is made from the root that has long been used there as a potency remedy. In English it is also called longjack.

Supplements use a standardised water-soluble extract, often 200 to 400 mg a day. Those are also the doses from the trials. The trials are small and mostly come from Malaysia, where the maker of the extract is based.

That is not a disqualification. It is a reason to read the numbers twice.

Why is tongkat ali banned?

Tongkat ali is banned because it is an unauthorised novel food. Herbal preparations with tongkat ali were not, or hardly, on the European market before 15 May 1997. That puts them under the novel food rules. A novel food may only be sold after a safety assessment.

EFSA carried out that assessment, and the outcome was bad. EFSA concluded that tongkat ali is genotoxic. In the NVWA's words: it can damage the genetic material in a cell and cause mutations. That may lead to cancer.

So it is not on the EU Union list and its sale in the Netherlands is banned. The NVWA inspects for it: in 2024 it found tongkat ali products at 10 companies. Against web shops outside Europe the NVWA has no legal means. And that is still where most tongkat ali comes from.

What does tongkat ali do to your body?

The trials show a rise in testosterone, but in specific groups and partly in saliva. Talbott followed 63 moderately stressed adults, 32 men and 31 women, for four weeks. Salivary cortisol fell by 16 percent. Salivary testosterone rose by 37 percent (Talbott 2013, PMID 23705671).

Saliva is not blood. A salivary value swings a lot, and a Dutch lab reports testosterone from serum. That 37 percent does not translate one to one to your lab report.

The strongest blood study comes from Malaysia. Of 76 men with late-onset hypogonadism, 35.5 percent had normal testosterone before the study. After a month of 200 mg a day it was 90.8 percent (Tambi 2012, PMID 21671978).

Henkel followed 25 active seniors aged 57 to 72. They took 400 mg a day for five weeks. Total and free testosterone rose, and so did muscle strength (Henkel 2014, PMID 23754792). In the women, the rise in free testosterone came mainly from a fall in SHBG.

What is missing: a trial in young, trained men with normal values. Exactly the group that buys it.

What are the possible side effects of supplements like this?

The side effects of tongkat ali reported in the trials are mild. Restlessness, poor sleep and a warm feeling. EFSA's concern is about something else. You do not notice genotoxicity, and the risk adds up over years.

A second risk comes on top. Products from foreign web shops are not inspected. Heavy metals and unlabelled medicines have been found before in herbal supplements from that corner.

The Dutch RIVM warned against ashwagandha in March 2024, after reports of liver damage. Tongkat ali is one step further along: there the regulator has banned the sale itself.

Which supplements are nonsense?

Nonsense is a big word, but most testosterone boosters do not make the grade. Of 50 boosters researchers screened in 2020, 24.8 percent had data showing a rise. In 10.1 percent testosterone actually fell (Clemesha 2020, PMID 31385468).

Tongkat ali is not the biggest nonsense in that line-up. It is the only herb that is banned. That is a different category.

Which supplements do something measurable, and in whom, is in the overview of testosterone supplements.

Already used it? This is what you can measure

Imagine you have used tongkat ali from an American web shop for six months. And you are reading this now. Panic does not help. Measuring does.

Total testosterone, free testosterone and SHBG come together in the hormone panel. The other values are measured separately via the biomarker pages. Creatinine is in 360 health; liver values are measured separately or as an add-on.

Genotoxicity does not show in a blood test. That is exactly why EFSA and the NVWA do not leave that risk to the user.

What you can do with this

My line: I write about tongkat ali because you buy it anyway, not because I recommend it. The trials are smaller than the marketing, and the regulator has taken it off the shelf.

Want something that has been measured and is allowed? Read what ashwagandha measured in athletes, with the RIVM's caveat alongside.

Or start at the boring end. Zinc and vitamin D raise testosterone only when you are short of them. And that you can measure.

If a value is off, discuss it with your GP and say what you have used. Every blood test result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.

References

• NVWA. Inspectieresultaten tongkat ali (Eurycoma longifolia Jack) 2024. nvwa.nl.
• Talbott SM, Talbott JA, George A, Pugh M. Effect of Tongkat Ali on stress hormones and psychological mood state in moderately stressed subjects. J Int Soc Sports Nutr. 2013 (PMID 23705671).
• Tambi MI, Imran MK, Henkel RR. Standardised water-soluble extract of Eurycoma longifolia, Tongkat ali, as testosterone booster for managing men with late-onset hypogonadism? Andrologia. 2012 (PMID 21671978).
• Henkel RR, Wang R, Bassett SH, et al. Tongkat Ali as a potential herbal supplement for physically active male and female seniors, a pilot study. Phytother Res. 2014 (PMID 23754792).
• Clemesha CG, Thaker H, Samplaski MK. 'Testosterone Boosting' Supplements Composition and Claims Are not Supported by the Academic Literature. World J Mens Health. 2020 (PMID 31385468).
• RIVM. RIVM raadt gebruik producten met kruiden Huperzia serrata, Tabernanthe iboga of ashwagandha af. 5 maart 2024.