Man lifting barbell weight over head

Is Tongkat Ali a Natty T Booster?

Research suggests the ancient herb can boost T, improve ED, and increase fertility.
By Austin Letorney
May 11, 2024

Fast Facts

  • Tongkat Ali is a herb grown in many parts of South Asia.
  • Some studies suggest that it may increase testosterone levels.
  • Tongkat Ali may also lower stress, improve erectile dysfunction, and aid in athletic performance.

The number of supplements that claim to boost testosterone is long—very, very long—and ranges from the scammy to the evidence-supported (vitamin D and fadogia agrestis). One supplement rising to the forefront of the latter category: Tongkat Ali, an ancient remedy with support from modern science.

A meta-analysis published in Medicina in 2022 (1). found that men (both those with normal T levels and those with a clinical testosterone deficiency) who supplemented with Tongkat Ali saw significant improvements in their testosterone levels. 

The same meta-analysis noted that some studies found the herb improved infertility and erectile dysfunction, aided in muscle growth, reduced fatigue, and boosted athletic performance —all common symptoms of testosterone deficiency.

“I’ve seen men benefit from taking Tongkat Ali, especially when combined with testosterone replacement therapy,” says Anastasia Jandes, M.D., who specializes in male hormone health.

What is Tongkat Ali?

Tongkat Ali, also called Longjack or eurycoma longifolia, is an herb grown throughout South Asia. 

“There are actually three different varieties, depending on where it is grown, but the one that’s most studied when it comes to boosting testosterone is the Malaysian Ginseng type,” says Jandes. 

It’s best known as a vitality and masculinity enhancer, says Jandes—”Malaysian men put it in their morning coffee or tea to boost virility,” she says. They also use Tongkat Ali to reduce stress, enhance muscle gains, and yes, boost testosterone levels. 


How Does Tongkat Ali Boost Testosterone?

Tongkat Ali appears to boost testosterone levels both directly and indirectly.

Increasing free and total testosterone

Tongkat Ali’s ability to boost testosterone production may not be just folklore. One study found that the herb increased men’s T levels by 37% after only four weeks of use (2). Another found that taking the herb boosted study participants’ total testosterone levels by 15% and their free testosterone levels by 34% (3).

The possible mechanism? A bioactive ingredient in the herb, called eurycomanone, activates the adrenal and pituitary glands, which results in the production of more total testosterone, says Jandes. She adds, “Free testosterone is the form that is not attached to sex hormone binding globulin (SHBG) or other serum proteins. Tongkat Ali may reduce the amount of total T bound to SHBG thereby increasing Free T.”

Eurycomanone has also been linked to higher levels of total testosterone and DHEA, a precursor to testosterone. “DHEA is an androgen that converts to testosterone or estrogen (estrogen is made from testosterone),” says Jandes. 

Improving sleep and reducing stress

Tongkat Ali contains phytochemicals known as quassinoids, says Jandes, which are purported to increase overall sleep quality and REM sleep, the deep restorative stage. “Research suggests testosterone production is closely tied with REM sleep. The bulk of REM sleep seems to occur during the last 4 hours of sleep and especially during the last 60-90 minutes of an 8-hour sleep cycle,” says Jandes. “This is why 8 hours of sleep is very important for men struggling with low T.”

Quassinoids also appear to lower cortisol levels. “Quassinoids have been shown to decrease salivary cortisol levels in human trials,” Jandes points out. “In hypogonadic men, the low levels of testosterone have been associated with inflammation, but it is just a correlation, no causal relationships have been identified.” She adds, “As cortisol levels decrease, inflammation and the stress response improve.” 

Other Benefits of Tongkat Ali

Stronger erections

In the meta-analysis published in Medicina, Tongkat Ali improved the quality of men’s erections.

Another study, published in 2021, found older men with ED had improvements in erectile function when they combined Tongkat Ali supplement with a strength training program (4).

Jandes says that the herb may increase levels of nitric oxide, a molecule that relaxes the muscles of your blood vessels and allows them to widen so more blood can flow to your penis.

Like the erectile dysfunction drugs sildenafil and tadalafil, Tongkat Ali may also improve blood flow. Researchers suspect Tongkat Ali may do this by preventing the breakdown of cyclic guanosine monophosphate (cGMP), a signaling molecule that relaxes smooth muscle tissue in response to things like nitric oxide, says Jandes.

And better blood flow equals stronger erections

Stronger libido

The Medicina meta-analysis noted that Tongkat Ali has been added to more than 700 products marketed as aphrodisiacs. 

And it may not be just filler. In one Universiti Sains Malaysia study (5) men who took 300 mg of Tongkat Ali extract twice daily for 12 weeks increased subjective measures of libido from baseline by up to just over 14%. 

Further study is required, but the effect likely has to do with rising testosterone levels; a lack of sex drive is a common symptom of low testosterone.

Improved fertility

Taking Tongkat Ali may also lead to healthier sperm.

The herb decreases the conversion of testosterone to estradiol, the predominant form of estrogen in men, and the form we typically measure. This increases testosterone levels and sperm production, says Jandes.   

Several studies suggest that Tongkat Ali may boost fertility by improving sperm count and motility. In one study, men who took 200 mg of Tongkat Ali daily for nine months had significant improvement in sperm concentration and motility. The treatment may have helped 14% of couples in the study become pregnant (6). 

Another finding from the Universiti Sains Malaysia study was that men who took 300 mg of the herb daily had 18% more sperm volume and 44% sperm motility.

Improved strength and endurance

Several studies with Tongkat Ali have demonstrated increased muscle force and increased gains in the gym, says Jandes. 

We know we’re starting to sound like a broken record here, but again, increased T is likely the route to better muscles and overall athletic performance. Higher testosterone levels are associated with increased muscle mass.

The eurycomanone in Tongkat Ali may also help improve endurance, according to a review of its effects (7). And in a small 8-week study, men who took 200 mg of the herb daily while strength training experienced significantly greater increases in peak power output than those taking a placebo (8). 


Supplementing With Tongkat Ali

If you’re interested in taking Tongkat Ali, a dose between 100-500 mg per day appears to be safe for most men, says Jandes. Of course, talk to your doctor before starting Tongkat Ali or any supplement. 

Side effects

There’s limited research on Tongkat Ali’s side effects. But research to date suggests that men with weakened immune systems should take a cautious approach to supplementing. And there’s a recommendation to avoid the herb in men with various health conditions such as prostate cancer, heart disease, kidney disease, diabetes, and others, along with interactions with some medications—your physician will need to perform an herb-drug interaction check with your medication list. Be sure to speak to your physician before taking Tongkat Ali. (9).

The Bottom Line

Research has begun to suggest that Tongkat Ali may boost testosterone and libido, reduce stress, and improve male fertility. While generally safe at doses between 100-500 mg per day, you should always talk to your doctor before taking any supplement.