Tongkat Ali: Benefits, Testosterone, Side Effects and UK Legal Status

What is tongkat ali?

Tongkat ali is a herbal supplement made from the root of Eurycoma longifolia, a slender tree native to Malaysia, Indonesia and neighbouring countries. It’s also called longjack or Malaysian ginseng. The root has been used in traditional medicine there for fever, low libido and tiredness, and today it’s sold mainly to men for testosterone, libido and gym performance.

Supplements usually contain a hot water extract of the root, standardised to compounds such as eurycomanone and glycosaponins. Physta is one branded extract. Ratios like “200:1” describe how concentrated an extract is, not how well it works. It is not related to true ginseng; see our guide to ginseng for that.

Is tongkat ali legal in the UK?

Tongkat ali is not authorised as a food in Great Britain. The EU Novel Food Catalogue lists all parts of Eurycoma longifolia as a novel food, and it isn’t on the FSA’s register of authorised novel foods (checked 10 November 2026). So UK sellers of tongkat ali supplements may be selling an unauthorised novel food.

• What a novel food is: a food or ingredient that wasn’t eaten to a significant degree in the UK or EU before 15 May 1997. It needs a safety assessment and authorisation before it can be sold as food.
• What happened to the application: a Malaysian extract maker applied to the FSA in 2016; the case moved to the EU, where EFSA found the extract had the potential to damage DNA in lab and animal tests.
• Why you still see it for sale: it’s widely sold online and on marketplaces, often shipped from overseas, and some UK shops stock it. A product being on sale doesn’t mean it has been assessed.

We think it’s fair to say this plainly: as things stand, tongkat ali has no authorisation to be sold as a food or food supplement in Great Britain, and we couldn’t find it registered as a herbal medicine either.

What does tongkat ali do? What the trials show

Tongkat ali is mainly studied for testosterone, sexual function and stress hormones. A handful of small trials, many funded by the makers of the extract tested, report modest rises in testosterone and some mood scores. There are no authorised health claims for it in Great Britain, and long-term human safety data are lacking.

Several of these trials tested the same branded water extract, made by the company that funded them, so the results may not apply to other products. For herbs with a longer evidence trail for men, see ashwagandha for men, maca root and shilajit, each with its own cautions.

Does tongkat ali increase testosterone?

Possibly, by a modest amount, mainly in men whose testosterone is already low. A 2022 meta-analysis of five small trials found total testosterone rose with tongkat ali, but the trials were few, short and mostly industry-linked. It is not a treatment for low testosterone, which needs a GP blood test.

The NHS says genuinely low testosterone later in life, called late-onset hypogonadism, is uncommon and isn’t a normal part of ageing. Symptoms such as low sex drive, erection problems, low mood and poor sleep have many causes, including stress, alcohol and being overweight. A GP can arrange a blood test and, if testosterone is low, refer you to a specialist. See our guide to the male menopause.

If a product promises to “boost testosterone”, remember that no such claim is authorised for any supplement ingredient in Great Britain. Zinc is the one nutrient with an authorised claim here: it contributes to the maintenance of normal testosterone levels in the blood. See our guide to zinc, and to magnesium for men for what that mineral’s claims do and don’t cover.

Does tongkat ali help with stress?

One small trial suggests it might affect stress hormones, but that’s far from proven. In 63 moderately stressed adults, four weeks of a tongkat ali root extract lowered salivary cortisol and improved some mood scores compared with placebo. The study was funded by the extract maker and hasn’t been widely repeated.

For stress that’s affecting your life, the basics come first: sleep, activity, alcohol and talking to someone. Our guides to supplements to lower cortisol and stress in men compare the options and their cautions.

How much tongkat ali a day?

Trials have mostly used 100 to 200mg a day of a standardised tongkat ali root water extract, for 4 weeks to 6 months. There is no UK-approved amount, because tongkat ali isn’t authorised as a food here, and EFSA couldn’t establish a safe intake even for the 200mg a day proposed by the applicant.

• Check the extract, not just the mg: “200mg of 200:1 extract” and “200mg of root powder” are very different products.
• Higher isn’t better: there’s no evidence that taking more than the trial amounts helps, and safety at any dose isn’t established.
• Count every product: tongkat ali turns up in “men’s” blends and pre-workouts, so check labels before you add another.

Is tongkat ali safe? Side effects and contamination

Short trials report few side effects, but tongkat ali’s safety isn’t established. EFSA found a root extract had the potential to damage DNA, a case of liver injury was published in 2024, and Malaysian testing found mercury or lead above local limits in a share of tongkat ali products. Long-term safety is unknown.

Those contamination studies are 20 years old and from Malaysia, and they don’t tell you about any product sold in the UK today. But because tongkat ali isn’t authorised as a food here, products on sale haven’t been through a UK safety assessment. For erection problems, the NHS warns that many websites sell fake medicines.

iStop taking it and see a GP urgently if you notice yellowing of your skin or eyes, dark pee, itching or pain on the right side of your tummy.

Who should not take tongkat ali?

Avoid tongkat ali if you’re under 18, pregnant or breastfeeding, have a hormone-sensitive condition such as prostate or breast cancer, have heart disease, or have liver or kidney disease. If you take any regular medicine, including for blood pressure or diabetes, check with your GP or pharmacist first.

• Hormone-sensitive conditions: it’s sold to raise testosterone, so it isn’t suitable alongside prostate cancer, breast cancer or other hormone-sensitive conditions, or with testosterone therapy.
• Heart disease: speak to your cardiologist or GP before any supplement sold for testosterone or performance.
• Pregnancy and breastfeeding: EFSA’s assessment excluded pregnant and breastfeeding women.
• Under 18s: not for children or teenagers.

Tongkat ali and medicines

Tongkat ali can change how some medicines are absorbed. In a study of 14 healthy men, taking 200mg of tongkat ali extract with the beta blocker propranolol lowered the amount of propranolol reaching the blood by 29%. Speak to your GP or pharmacist first if you take any regular medicine.

• Blood pressure medicines: as above for propranolol; see do beta blockers make you tired? and normal blood pressure by age.
• Diabetes medicines: the root is traditionally used for diabetes, so check before combining; see does diabetes make you tired?
• Other supplements sold for testosterone or blood flow: don’t stack several at once, such as L-arginine with tongkat ali, without advice.

Never stop or change a prescribed medicine to try a supplement.

When to see a GP instead

See a GP if you have low sex drive, low energy or low mood that won’t lift, or erection problems that keep happening. The NHS says erection problems that keep happening might be a sign of a health condition that can be treated, such as high blood pressure, high cholesterol or diabetes. A blood test can check testosterone.

Our guides to supplements for men over 50 (and 40) and Movember and men’s health cover the checks worth having.