Tongkat Ali / Longjack

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 (5Trusted Source).

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 (3Trusted Source, 6, 7Trusted Source, 8Trusted Source).

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

SummaryTongkat ali is an herbal medicine derived from the Southeast Asian Eurycoma longifolia shrub. It contains several potentially beneficial compounds and is used to treat a variety of ailments, including male infertility and infections.

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 (9Trusted Source).

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 (9Trusted Source, 10Trusted Source, 11Trusted Source).

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 (11Trusted Source).

What’s more, studies in both animals and humans show that taking tongkat ali stimulates sexual arousal and may improve erectile dysfunction in men (12Trusted Source, 13Trusted Source, 14Trusted Source, 15Trusted Source).

Finally, tongkat ali may improve sperm motility and concentration, boosting male fertility (1Trusted Source, 15Trusted Source, 16Trusted Source, 17Trusted Source, 18Trusted 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 (1Trusted Source).

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 (15Trusted Source).

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 (19Trusted Source).

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 (2Trusted Source).

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

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 (3Trusted Source).

In other words, the supplement may act as an ergogenic aid, which is a substance that can enhance physical performance and improve body composition (3Trusted Source, 20).

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 (21).

They also lost more fat than participants in the placebo group (21).

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 (22Trusted Source).

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 (23Trusted Source).

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.

SummaryStudies show that tongkat ali may boost testosterone levels and help treat infertility in men, relieve stress, and possibly increase muscle mass. Still, more extensive research is needed.