Tongkat Ali: What the Research Says, Dosage and Side Effects

Does tongkat ali work? Possibly, for some men: small trials suggest a standardised tongkat ali root extract can raise testosterone a little, mostly in men whose levels started low, but the studies are few, short and often funded by the companies that make the extract. Below: the research, study doses, side effects, LJ100, and tongkat ali vs ashwagandha and fadogia agrestis.

What is tongkat ali?

Tongkat ali (Eurycoma longifolia), also sold as longjack, is a tree native to Southeast Asia. Its root has a long history in traditional medicine there, and supplements use root extracts. Researchers usually measure a compound called eurycomanone to judge the strength of an extract (Farag and colleagues, 2023). Today it is mostly marketed for testosterone, libido, energy and stress.

Does tongkat ali work? What the research says

Testosterone. The largest analysis so far, a 2022 systematic review, looked at nine studies and pooled five randomised trials with 232 men. Total testosterone rose more with tongkat ali than with placebo, and the rise was clearest in men who started with low testosterone. The authors flagged weak points: few, small and very different trials, results that varied widely and signs of publication bias (Leisegang and colleagues, 2022).

Stress and mood. In a four-week trial, 63 moderately stressed adults took 200 mg a day of a standardised extract or a placebo. The tongkat group had lower saliva cortisol, higher saliva testosterone and better scores for tension, anger and confusion. The extract maker funded the study (Talbott and colleagues, 2013).

Sexual function. A 2015 meta-analysis could only pool two trials with 139 men and found no clear overall difference from placebo in erectile function scores, although men with lower scores at the start did improve (Kotirum and colleagues, 2015).

The honest summary: research suggests tongkat ali may help some men, mainly those with low testosterone, but the evidence is small, mixed and largely industry funded. If you think your testosterone is low, see your GP for a blood test rather than relying on supplements.

Tongkat ali dosage: what studies used

These are the amounts researchers used, not a personal recommendation. Always follow your product label.

• Amount: trials in the 2022 review used 100 to 600 mg of root extract a day, most often 100 to 300 mg.
• Length: from 3 days to 6 months, with many trials running 4 to 12 weeks.
• Extract: seven of the nine studies used Physta, a freeze-dried water extract standardised to 0.8 to 1.5 percent eurycomanone.

What is LJ100? According to the 2023 review by Farag and colleagues, LJ100 is the name the same patented extract is sold under in the United States, so a label listing LJ100 or Physta uses the type of extract tested in most of the research.

Ratio extracts are different. Many tongkat products, including the ones we stock, list a ratio such as 200:1 rather than a standardised eurycomanone level. A ratio describes how much raw root went into the extract, not how much of the marker compound is in each capsule, so a 400 or 500 mg capsule cannot be compared directly with a trial dose. Quality also varies: in a Malaysian survey cited by the 2022 review, only 11 of 41 tongkat products had eurycomanone within the recommended range, and some had none.

Tongkat ali side effects and safety

Most trials lasted weeks to a few months, so long-term safety is unknown. Within those trials, few side effects were reported: one trial noted stomach symptoms and itching, and studies that checked liver enzymes found no changes (Leisegang and colleagues; Talbott and colleagues).

Product quality can be a bigger worry than the herb: testing in Malaysia found some tongkat products with lead or mercury above local limits, according to the 2023 review. Buy established brands and stick to the label dose.

Labels carry their own warnings too. Allmax, for example, says not to use its tongkat if you are under 18, pregnant, breastfeeding or taking prescription medication. Because tongkat ali is marketed for its effects on hormones, talk to your GP or pharmacist first if you have a medical condition or take regular medicines.

Drug-tested athletes: the Australian Institute of Sport (AIS) lists "Tribulus terrestris and other testosterone boosters" in Group D of its Sports Supplement Framework: ingredients that are banned or at high risk of contamination with substances that could cause a positive test, and are not to be used by athletes (AIS Group D). Tongkat ali is usually sold as a testosterone booster, so check with your sport first and read our guide to supplements for drug-tested athletes.

Tongkat ali vs ashwagandha vs fadogia agrestis

These are often grouped as "natural testosterone" herbs, but the evidence differs a lot.

Tongkat ali vs ashwagandha. The NIH Office of Dietary Supplements says ashwagandha extracts may help reduce stress and anxiety and improve sleep, and might also increase testosterone, but most trials are small and short. Side effects are usually mild, such as stomach upset, loose stools, nausea and drowsiness, though there are rare reports of liver problems, and it might not be safe in pregnancy or breastfeeding (NIH ODS ashwagandha fact sheet). If stress and sleep are your main goals, ashwagandha has more research behind it. Tongkat ali has been studied more directly for testosterone, though the effects are modest. Our ashwagandha guide goes into more detail.

Fadogia agrestis. Fadogia is a shrub used in traditional African medicine (Avula and colleagues, 2019). In rats, a stem extract raised testosterone over five days (Yakubu and colleagues, 2005), but a 28-day study at the same doses found changes in testicular function markers that the authors described as adverse effects (Yakubu and colleagues, 2008), and another found signs of damage to liver and kidney cell membranes (Yakubu and colleagues, 2009). We could not find any published human trials. Quality is a problem too: in the 2019 analysis, 5 of 17 supplements sold as fadogia contained none of the plant's marker compounds.

Tongkat ali and fadogia agrestis together. This stack is popular online, but no human trial has tested the combination, and fadogia has no human safety data. For that reason we have not featured fadogia products in this guide.

Products to look at

These single-ingredient tongkat products are stocked at Supps247. Figures come from each label; none state a standardised eurycomanone level, so they cannot be matched exactly to study doses.

Browse the full testosterone support range, or the ashwagandha range if stress or sleep is your main goal. Drug-tested athletes should check every product with their sport.

FAQs

Does tongkat ali work for testosterone?

Research suggests it may, modestly. A 2022 review pooling five randomised trials found total testosterone rose more with tongkat ali than with placebo, with the clearest effect in men who started with low levels. The trials were small and varied a lot, and most used one branded extract. If you think your testosterone is low, see your GP for a blood test first.

How much tongkat ali should I take?

Follow your product label. For context, trials used 100 to 600 mg a day of a standardised root extract, most often 100 to 300 mg, for anywhere from a few days to six months. Most products on shelves list a ratio such as 200:1 instead of a standardised level, so their capsules cannot be compared directly with the doses used in studies.

What are the side effects of tongkat ali?

Short trials reported few side effects, with stomach symptoms and itching noted in one study and no liver enzyme changes in studies that checked. Long-term safety is unknown, and some products tested in Malaysia contained lead or mercury above local limits. Avoid it if you are under 18, pregnant or breastfeeding, and check with your GP or pharmacist if you take medication.

Is tongkat ali better than ashwagandha?

They suit different goals. Tongkat ali has been studied mainly for testosterone, with small and mixed results. Ashwagandha has more trials for stress, anxiety and sleep, according to the NIH Office of Dietary Supplements, though most are small and short. Ashwagandha might not be safe in pregnancy and has rare reports of liver problems, so talk to your GP before using either with medication.

Can I take tongkat ali and fadogia agrestis together?

The combination is popular online, but no human trial has tested it, and we could not find any published human trials of fadogia on its own. In rats, fadogia caused changes in the testes, liver and kidneys at the same doses that raised testosterone in a shorter study. Until there is human safety data, we suggest caution and a chat with your GP before trying fadogia.

Sources: Leisegang and colleagues, Medicina (2022); Talbott and colleagues, JISSN (2013); Kotirum and colleagues, Complementary Therapies in Medicine (2015); Farag and colleagues, ACS Omega (2023); NIH ODS, ashwagandha fact sheet; AIS Sports Supplement Framework, Group D; Yakubu and colleagues, Asian Journal of Andrology (2005); Yakubu and colleagues, Journal of Ethnopharmacology (2008); Yakubu and colleagues, Human and Experimental Toxicology (2009); Avula and colleagues, Planta Medica (2019); product label images.

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Always read the label and follow the directions for use. If you have a medical condition, are pregnant or take regular medication, check with your doctor first.