Tongkat Ali Side Effects: What to Know Before You Take It

Tongkat ali, also called longjack or Eurycoma longifolia, is a Southeast Asian root that shows up in a lot of men's testosterone support formulas. It's one of the better-studied botanicals in the category, which is part of why it's so popular.

But "natural" doesn't mean side-effect free. Here's what the research and real-world reports actually say about tongkat ali side effects, who should skip it, and how to lower your risk if you take it.

This article is general information, not medical advice. Your doctor knows your health history and medications; we don't.

Common tongkat ali side effects

Most clinical trials on tongkat ali were designed to measure benefits, not to carefully track side effects, so there's no reliable data on how often each one happens. These are the ones that come up most consistently in studies, drug references and user reports:

• Trouble sleeping. The most commonly reported side effect, especially at higher doses or when taken later in the day.
• Restlessness and irritability. Some men describe feeling wired or short-tempered.
• Stomach upset. Nausea, abdominal discomfort or diarrhea, particularly on an empty stomach.
• Headaches. Reported occasionally.
• Itching. Noted in some human studies.

For most people, these are mild. Many fade as the body adjusts or go away when the dose is lowered or taken earlier in the day. If a side effect is strong or doesn't go away, stop taking it.

The bigger risks most articles skip

1. Product quality and contamination

This is arguably the most important safety issue with tongkat ali, and it has nothing to do with the plant itself.

Researchers testing tongkat ali products sold in Malaysia, the main source country, found that roughly a quarter to a third of them contained mercury above Malaysia's safety limit for traditional medicines. Other tongkat products have been found contaminated with lead, or adulterated with sildenafil, the active drug in Viagra, which isn't listed on the label.

The plant name also causes confusion. "Tongkat ali" is used for more than one species in Southeast Asia, and some cheap products may not contain real Eurycoma longifolia at all.

What that means for you: where you buy matters. Look for a brand that names the species, prints the dose, and says its products are third-party tested.

2. Medication interactions

• Propranolol. A small study in healthy volunteers found tongkat ali reduced how much propranolol, a beta-blocker used for blood pressure and heart conditions, the body absorbed. If you take propranolol or another blood pressure medication, talk to your doctor first.
• Blood sugar medications. Tongkat ali may lower blood sugar, so it could add to the effect of diabetes medications.
• Other medications. Possible interactions with immunosuppressants and blood thinners have been raised, mostly on theoretical grounds. If you take any prescription medication, check with your doctor or pharmacist.

3. Long-term safety hasn't been established

Most human studies on tongkat ali last weeks to a few months. There's very little data on taking it for years.

It's also worth knowing that in 2021 the European Food Safety Authority reviewed tongkat ali root extract and said its safety had not been established, citing animal data suggesting a potential for DNA damage. Tongkat ali isn't authorized as a food supplement ingredient in the UK. In the US, it's sold as a dietary supplement. None of this proves harm in people at normal doses, but it's a fair reason to use it thoughtfully rather than indefinitely without a check-in.

Who should not take tongkat ali

• Anyone pregnant or breastfeeding. There isn't enough safety data.
• Anyone under 18. Testosterone support products aren't meant for teens.
• Men with hormone-sensitive conditions, including prostate cancer or other hormone-related cancers, unless their doctor approves it.
• Anyone on TRT or other hormone therapy, without talking to their doctor first.
• Anyone taking propranolol, blood pressure medication or diabetes medication, without a doctor's sign-off.
• Anyone with a sleep problem or anxiety disorder, since insomnia and restlessness are the most common side effects.

How much tongkat ali is typically used?

Most human studies have used roughly 200 to 400mg a day of a standardized root extract. Some products contain more, and raw root powder isn't directly comparable to a concentrated extract, so milligram numbers across brands don't always mean the same thing.

Reports of insomnia, irritability and restlessness tend to cluster at higher doses. Taking more than the amounts used in research doesn't have good evidence behind it and appears more likely to cause side effects.

For reference: Mars Men contains 500mg of tongkat ali root extract per daily serving as of October 2026. We broke down the full formula in our Mars Men review.

How to lower your risk if you take it

• Buy from a brand that prints the dose and says it's third-party tested.
• Start with the label dose, not more.
• Take it with food if it bothers your stomach.
• Pay attention to sleep. If you're sleeping worse, try taking it earlier in the day, lowering the dose, or stopping.
• Get bloodwork before you start and again after a few months. It's the only way to know what it's actually doing for you.
• Stop and call your doctor if you notice a racing heart, severe headaches, chest discomfort, or any reaction that worries you.

Does tongkat ali actually work?

The evidence is mixed but more promising than for many herbs in this category. A number of small human studies have found modest improvements in testosterone, stress markers or sexual function, most often in men who started with low levels or high stress. Results in men with normal levels are less impressive. For a broader look at the botanicals in this space, see our guide to herbs for testosterone support.

Tongkat ali in Blue Collar Nutrition products

Since we sell products that contain it, here's exactly where it shows up, with the amounts printed on our labels:

• Hammer contains 400mg of longjack (tongkat ali) root per two-tablet serving, taken about an hour before bed. Because trouble sleeping is the most common tongkat side effect, pay attention to how you sleep. If you notice it's worse, stop and talk to your doctor.
• Overdrive Men's contains a much smaller 50mg of tongkat ali root per three-capsule serving, taken in the morning after breakfast, alongside tribulus, chrysin, epimedium and other ingredients, every dose printed.
• The Rock-Hard Pack includes both Hammer and Overdrive Men's, so you'd be taking both amounts.

Every Blue Collar Nutrition product is made in the USA with global ingredients and third-party tested. If you want the reasoning behind how these products work together, it's laid out in the Rock-Hard formula breakdown.

Frequently asked questions

What are the side effects of tongkat ali?
The most commonly reported side effects are trouble sleeping, restlessness and irritability, especially at higher doses. Some people also report stomach upset, headaches or itching. Most are mild and ease with a lower dose or earlier timing.

Is tongkat ali safe?
Short-term human studies suggest it's generally well tolerated at typical doses. The main concerns are contaminated or mislabeled products, a possible interaction with the blood pressure drug propranolol, and limited data on long-term use. In 2021 the European Food Safety Authority said its safety had not been established, citing animal data. Talk to your doctor before starting it, especially if you take medication.

Can tongkat ali cause insomnia?
Yes. Trouble sleeping is the most commonly reported side effect, and it's more likely at higher doses or when taken later in the day. Taking it earlier or lowering the dose often helps.

Does tongkat ali raise blood pressure?
It isn't generally linked to raising blood pressure in men at typical doses, but it may interact with blood pressure medications. A small study found it reduced the absorption of propranolol, a beta-blocker. If you take blood pressure medication, check with your doctor first.

Who should not take tongkat ali?
People who are pregnant or breastfeeding, anyone under 18, men with hormone-sensitive conditions such as prostate cancer, anyone on TRT or hormone therapy, and anyone taking propranolol, blood pressure or diabetes medication without a doctor's approval.

How much tongkat ali is safe to take?
Most human studies have used about 200 to 400mg a day of a standardized extract for up to several months. Side effects appear more common above that range. Follow the label and talk to your doctor before taking more.

Can tongkat ali be contaminated?
Yes. Studies of products sold in Malaysia found that roughly a quarter to a third exceeded the safety limit for mercury, and some tongkat products have been found with lead or hidden sildenafil. Buy from a brand that names the species, prints the dose and says it's third-party tested.

Does Hammer contain tongkat ali?
Yes. Hammer contains 400mg of longjack (tongkat ali) root per two-tablet serving. Overdrive Men's contains 50mg per three-capsule serving.

These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease. Consult your physician before beginning any supplement, particularly if you have a medical condition or take prescription medication.