Eurycoma longifolia or Tongkat Ali is a tree indigenous to South-East Asian countries such as Malaysia, Indonesia, and Thailand. The root of the tree bears compounds called quassinoids and alkaloids. It is the component of the tree that is medicinally used. Tongkat Ali is normally consumed in dietary supplements, tea, coffee drinks, or energy drinks.
Other monikers for tongkat ali include Eurycoma longifolia Jack, longjack, wonod mondou. payung ali, Malaysian ginseng, tung saw, and umpudumaidu.
Applications for Tongkat Ali
In alternative medicine, best quality Tongkat Ali is used for increasing testosterone levels, promoting muscle strength, and addressing several conditions: erectile dysfunction, decreased libido, fatigue, and stress.

Erectile Dysfunction and Low Libido
Tongkat Ali is often referred to as a remedy for erectile dysfunction. There is some preliminary evidence that this may help. For example, a small study published in Evidence-Based Complementary and Alternative Medicine found that twelve weeks of supplementation of the product containing Eurycoma longifolia extract and Polygonum minus (antioxidant) helped enhance erectile function and sexual performance.
Another study, also published in Evidence-Based Alternative and Complementary Medicine, suggests that Tongkat Ali extract may help in the treatment of low libido and erectile function. Involving 109 males between 30 and 55 years of age, the study found that the extract may increase sexual libido, erectile function, sperm motility, and semen volume. Loss of fat mass was also noted in those who were overweight.
Building Muscle
Tongkat Ali may increase muscle mass and strength due to its alleged effects on testosterone levels. It is often used to boost physical performance, physical strength, and facilitate fat loss. In an introductory study published in the British Journal of Sports Medicine, researchers found that 100 mg/day of Eurycoma longifolia extract increased muscle mass and strength in men participating in an intensive strength training program for five weeks alone.
Best quality Tongkat Ali may also help increase muscle strength in older adults, according to a pilot study published in Phytotherapy Research in 2014. In a study, 13 males and 12 females aged between 57 and 72 took 400 mg of Tongkat Ali to be extracted daily for five weeks. After the research, Tongkat Ali was found to have increased free and total testosterone levels and muscle strength.
However, a 2010 study involving male recreation athletes found that 150 mg/day for seven days before endurance run (plus an hour before a run) did not improve endurance compared to placebo.
Infertility
Tongkat Ali is promising in the treatment of infertility, according to a preliminary study published in the Asian Journal of Andrology in 2010. Researchers discovered that 200 mg/day of men’s supplementation with Eurycoma longifolia for 3 to 9 months resulted in higher semen volume, sperm concentrations, percentage of normal sperm morphology, and sperm motility, and resulted in unexpected pregnancy in 11 of the participants’ partners after treatment.
Stress
Some research suggests that Tongkat Ali can help relieve stress. The research available includes a small study published in the Journal of the International Society for Sports Nutrition. Researchers evaluated stress hormones and mood conditions in 63 people before and after taking a Tongkat Ali supplement for four weeks. They found significant improvements in mood conditions of tension, confusion, and anger, as well as decreased salivary cortisol and increased testosterone in those taking Tongkat Ali extract.
Late-Onset Hypogonadism
According to a study published in Andrologia, Tongkat Ali may improve symptoms of late-onset hypogonadism. In the study, 76 people with late-onset hypogonadism received 200 mg of standardized Tongkat Ali extract for one month. Results suggested that the Tongkat Ali extract improved scores on the Aging Male Symptoms scale and testosterone levels.