Tongkat Ali Extract: Benefits, Side Effects, and Dosage

Tongkat ali, or longjack, is an herbal supplement that comes from the roots of the green shrub tree Eurycoma longifolia, which is native to Southeast Asia.

It’s used in traditional medicine in Malaysia, Indonesia, Vietnam, and other Asian countries to treat malaria, infections, fevers, male infertility, and erectile dysfunction (Trusted Source 4).

The health benefits of tongkat ali likely stem from various compounds found in the plant.

Specifically, tongkat ali contains flavonoids, alkaloids, and other compounds that act as antioxidants. Antioxidants are compounds that fight cellular damage caused by molecules called free radicals. They may benefit your body in other ways as well (Trusted Source 3, Trusted Source 5, Trusted Source 6, Trusted Source 7).

Tongkat ali is typically consumed in pills that contain an extract of the herb or as part of herbal drinks (Trusted Source 3).

Most of the alleged health benefits of tongkat ali are not well researched, but some studies suggest that it may help treat male infertility, improve mood, and increase muscle mass.

May increase testosterone levels and improve male fertility

Tongkat ali’s potential to increase testosterone in men with low levels of this primary sex hormone is well known and well documented.

Low testosterone can result from aging, chemotherapy, radiation treatments, some medications, injury or infection of the testicles, and certain diseases, such as chronic alcoholism and obstructive sleep apnea (Trusted Source 8).

Effects of inadequate testosterone levels include low libido, erectile dysfunction, and in some cases, infertility. Since compounds in tongkat ali may boost low testosterone, it could treat these issues (Trusted Source 8, Trusted Source 9, Trusted Source 10).

A 1-month study in 76 older men with low testosterone found that taking 200 mg of tongkat ali extract per day significantly increased levels of this hormone to normal values in over 90% of participants (Trusted Source 10).

What’s more, studies in both animals and humans show that taking tongkat ali stimulates sexual arousal and may improve erectile dysfunction in men (Trusted Source 11, Trusted Source 12, Trusted Source 13, Trusted Source 14).

Finally, tongkat ali may improve sperm motility and concentration, boosting male fertility (Trusted Source 1, Trusted Source 14, Trusted Source 15, Trusted Source 16, 17Trusted Source).

One study in 75 male partners of couples with infertility found that taking 200 mg of tongkat ali extract per day significantly improved sperm concentration and motility after 3 months. The treatment helped over 14% of couples become pregnant (Trusted Source 1).

Similarly, a 12-week study in 108 men ages 30–55 observed that taking 300 mg of tongkat ali extract daily increased sperm volume and motility by an average of 18% and 44%, respectively (Trusted Source 14).

According to these studies, tongkat ali effectively treats low testosterone and infertility in some men, but more extensive research is needed.

May relieve stress

Tongkat ali may lower stress hormones in your body, decrease anxiety, and improve mood.

A 1999 study first identified the possible role of this remedy in treating mood issues and found that tongkat ali extract was comparable to a common anti-anxiety medication in reducing symptoms of anxiety in mice (Trusted Source 18).

Similar effects have been seen in humans, but research is limited.

A 1-month study in 63 adults with moderate stress found that supplementing with 200 mg of tongkat ali extract per day reduced levels of the stress hormone cortisol in saliva by 16%, compared to those who received a placebo (Trusted Source 2).

Participants also reported significantly less stress, anger, and tension after taking tongkat ali (Trusted Source 2).

While these results are promising, more studies in humans are needed.

May improve body composition

Tongkat ali is often claimed to boost athletic performance and increase muscle mass.

This is because it contains compounds called quassinoids, including eurycomaoside, eurycolactone, and eurycomanone, which may help your body use energy more efficiently, reduce fatigue, and improve endurance (Trusted Source 3).

In other words, the supplement may act as an ergogenic aid, which is a substance that can enhance physical performance and improve body composition (Trusted Source 3, Trusted Source 19).

A small, 5-week study in 14 men participating in a strength training program found that those who took 100 mg of tongkat ali extract per day experienced significantly greater increases in lean body mass than those taking a placebo (Trusted Source 20).

They also lost more fat than participants in the placebo group (Trusted Source 20).

What’s more, a 5-week study in 25 active older adults discovered that supplementing with 400 mg of tongkat ali extract daily significantly increased muscular strength, compared to a placebo (Trusted Source 21).

However, a small study in cyclists observed that consuming a drink with tongkat ali during exercise did not improve performance or strength any more than plain water (Trusted Source 22).

These conflicting results suggest that tongkat ali may exhibit some ergogenic effects, depending on the dose and length of treatment, but more research is needed.

The few studies on the use of tongkat ali in humans have not reported any side effects (Trusted Source 1, Trusted Source 2, Trusted Source 21).

One study noted that taking 300 mg of tongkat ali extract daily was as safe as taking a placebo. (Trusted Source 14).

Other studies suggest that taking up to 1.2 grams of tongkat ali extract per day is safe for adults, but this amount has not been used in research. Plus, no studies examine its long-term use, making it unclear whether the supplement is safe over longer periods (Trusted Source 23, Trusted Source 24).

What’s more, one study examining the mercury content of 100 tongkat ali supplements from Malaysia found that 26% had levels of mercury higher than the recommended limit (Trusted Source 25).

Consuming too much mercury can result in mercury poisoning, which is characterized by mood changes, memory problems, and motor skill issues (Trusted Source 26).

Furthermore, the effects of tongkat ali in children or pregnant and breastfeeding women have not been researched. Therefore, it’s unknown whether the remedy is safe for these populations.

Tongkat ali, or longjack, is an herbal supplement suggested to improve low testosterone, male fertility, anxiety, athletic performance, and muscle mass.