Tongkat ali has attracted a fair amount of scientific interest, much of it from Malaysia, where the government has backed research into the plant as a national crop. This guide sets out what kind of research exists and how much weight it can bear. It is not a summary of benefits, and it should not be read as one.
Why we do not make health claims
In Great Britain, a food supplement can only carry a health claim if that claim has been assessed and added to the government's register of authorised nutrition and health claims. There are no authorised health claims for tongkat ali. That means no seller, including us, can lawfully tell you that tongkat ali will do anything specific for your health, and you should be wary of any that do.
What kind of research exists
Most of the published work on tongkat ali falls into three groups. The first is laboratory and animal research, which looks at how compounds from the root behave in cells or in rodents. This is useful for understanding a plant but tells us very little about what happens in people.
The second group is small human trials. Researchers have looked at measures such as hormone levels, stress hormones, mood scores, energy and exercise recovery, usually over a few weeks and in groups of between a few dozen and around a hundred people. One frequently cited example is a 2013 study by Talbott and colleagues in the Journal of the International Society of Sports Nutrition, which followed 63 moderately stressed adults for four weeks and measured stress hormones and mood.
The third group is reviews that pool the results of several trials. These generally conclude that the findings are interesting but that the trials are small, short and varied in their methods, and that larger, independent studies are needed before firm conclusions can be drawn.
The limits of the evidence
- Small numbers. Most trials involve fewer than a hundred people, which makes chance findings more likely.
- Short timescales. Studies typically run for four to twelve weeks, so little is known about long term use.
- Different extracts. Trials use different extracts at different strengths, so a result from one product cannot be assumed to apply to another.
- Funding. A number of trials have been funded by companies that sell tongkat ali extracts, which does not make them wrong but is worth bearing in mind.
Reading the research yourself
If you want to look at the studies directly, PubMed, run by the US National Library of Medicine, is a free and reliable place to start. Search for Eurycoma longifolia rather than tongkat ali to find the scientific papers. Look at how many people took part, how long the study ran, whether there was a placebo group and who paid for it. If you are thinking of taking any supplement because of a health concern, the best first step is a conversation with your GP.
Last reviewed 2 November 2026