Tongkat Ali is a herbal supplement used as an aphrodisiac and testosterone booster. Not only can it enhance sexual health and performance, but it may also be beneficial in male osteoporosis, diabetes, and anxiety. Read more below to learn about the health benefits of Tongkat Ali, dosage, reviews, and side effects. 

What is Tongkat Ali?

Eurycoma longifolia, commonly known as Tongkat Ali, long jack, or Malaysian ginseng, is a plant found in the Malaysian rainforest [1].

It is best known for its ability to enhance libido, testosterone levels, erectile function, sexual performance, and fertility in men, giving it the name “Malaysia’s home-grown Viagra” [2].

However, this plant also has a variety of other benefits including:

  • Promoting bone formation [3]
  • Increasing muscle strength and athletic performance [4]
  • Improving physical and mental energy levels and overall quality of life [5, 6]
  • Reducing anxiety and stress [4]
  • Anticancer effects [7]
  • Antimicrobial and antifungal effects [8]
  • Antiulcer effects [9]
  • Antioxidant effects [10]
  • Lowering blood sugar [11]


The stem and root extracts of the Eurycoma longifolia plant contain:

  • Quassinoids (e.g., eurycomaoside, eurycomanone, pasakbumin-B): These compounds have anticancer, antiparasitic, and antiulcer effects [12, 9, 12].
  • Alkaloids, which have anticancer and antibacterial properties [13, 11, 14].

Mechanism of Action

Tongkat Ali increases testosterone levels by [15, 4]:

  • Stimulating the production of testosterone from pregnenolone and 17-OH-pregnenolone
  • Blocking aromatase, the enzyme that converts testosterone to estrogens

Tongkat Ali helps with male osteoporosis by [16]:

  • Stimulating bone cell growth (via testosterone)
  • Increasing the activity of alkaline phosphatase (ALP), an enzyme that plays a role in the development of bones and teeth
  • Enhancing the deposition and mineralization of collagen

Tongkat Ali helps with cancer by [12, 17, 18]:

  • Inhibiting tumor growth and progression (by inhibiting NF-κB)
  • Promoting cancer cell death

Tongkat Ali improves gut health by [9]:

  • Reducing excess stomach acid, which helps prevent ulcers

Health Benefits of Tongkat Ali

1) Tongkat Ali May Increase Testosterone

A 5-week pilot study of 25 seniors found that Tongkat Ali increased testosterone levels and muscle strength in both men and women [19].

Tongkat Ali supplementation also increased testosterone levels in a 4-week study of 76 men with hypogonadism (an impaired function of the testes) [6].

However, in a 15-week study (DB-RCT) of 13 recreational athletes, Tongkat Ali did not increase testosterone levels in the urine, prompting the researchers to conclude that it does not breach the International Olympic Committee doping policies [20].

Tongkat Ali significantly increased testosterone levels in rats [21].

2) Tongkat Ali Improves Male Fertility

A 12-week study (DB-RCT) of 109 men (ages 30 to 55) found that Tongkat Ali increased sperm motility and semen volume compared to placebo [5].

In another 9-month study of 75 males with infertility, Tongkat Ali supplements improved semen volume, sperm concentration, sperm motility, and sperm quality, thereby enhancing fertility [1].

Studies in rats also showed that Tongkat Ali reversed the inhibitory effects of estrogen on testosterone production and increased sperm production, count, concentration, motility, and vitality [22, 21, 23].

3) Tongkat Ali Improves Male Sexual Health

A 12-week study (DB-RCT) in 109 men found that Tongkat Ali increased libido and improved erectile function compared to placebo [5].

Similarly, a 12-week study (DB-RCT) of 26 men found that a freeze-dried water Tongkat Ali supplement improved sexual performance and increased the hardness and duration of erection [24].

Tongkat Ali also enhanced libido, sexual arousal, and performance in healthy, impotent, castrated, and old male rats, and middle-aged mice [25, 26, 27, 28, 29, 30].

4) Tongkat Ali May Enhance Muscle Strength

Tongkat Ali supplements increased muscle strength in both men and women in a 5-week pilot study of 25 seniors [19].

Similarly, in a 5-week pilot study of 14 healthy men, Tongkat Ali increased muscle strength and size and improved athletic performance [31].

5) Tongkat Ali May Promote Weight Loss

Tongkat Ali reduced fat mass, waist circumference, and hip size compared to placebo in a 12-week study (DB-RCT) of 109 men [5].

Another (pilot) study in 14 healthy men showed that Tongkat Ali supplements increased muscle strength and size while decreasing body fat after 5 weeks [31].

Tongkat Ali also reduced body weight and belly fat in mice. However, it did not affect the weight of the internal organs [21].

6) Tongkat Ali May Treat Male Osteoporosis

Tongkat Ali strengthens bones by [3]:

  • Increasing testosterone levels
  • Stimulating the production of osteoblasts, or bone-forming cells
  • Triggering the death of cells that break down bone tissue (osteoclasts)
  • Decreasing bone loss and preserving bone mass

Thus, it may be used for male osteoporosis treatment.

In the lab, Tongkat Ali activated the production of bone-building proteins (such as BMP-2, RUNX-2, and OCN), which increases bone formation [16, 32].

Tongkat Ali also prevented calcium loss in the bones of castrated male rats with osteoporosis [33, 34].

However, in another study, Tongkat Ali did not restore testosterone levels and bone volume in the castrated rats with osteoporosis [35].

7) Tongkat Ali May Combat Cancer

Tongkat Ali prevented the growth of subcutaneous (under the skin) tumors in mice [36].

Lab studies found that Eurycoma longifolia (the plant that Tongkat Ali originates from) contains specific compounds (quassinoids) that prevent cancer cell growth and progression [12, 17, 18, 36].

Other cell-based studies found that Tongkat Ali was effective against various types of cancers including leukemia, and lung and breast cancers. However, it only showed moderate effectiveness against gut cancer [7, 37].

8) Tongkat Ali May Reduce Stress And Anxiety

A 4-week study on 63 moderately stressed people showed that Tongkat Ali root extract reduced stress hormone (cortisol) levels, tension, anger, and confusion [15].

Tongkat Ali also reduced the frequency of fighting episodes and increased exploratory behavior in mice [38].

9) Tongkat Ali May Enhance the Immune System

In a 4-week study (DB-RCT) of 83 subjects, Tongkat Ali supplements increased T cells, CD4+ T cells, and naïve T cell numbers, which enhanced overall immune function [39].

10) Tongkat Ali May Reduce Blood Sugar

Tongkat Ali reduced blood sugar levels in diabetic rats [40].

11) Tongkat Ali May Decrease Blood Pressure

In rats, Tongkat Ali widened blood vessels, which lowered blood pressure [41].

12) Tongkat Ali Decreases Pain And Inflammation

In the lab, Tongkat Ali exhibited antioxidant (free radical scavenging) and anti-inflammatory properties [10].

13) Tongkat Ali May Combat Bacteria

Tongkat Ali inhibited the growth of harmful bacteria in the lab (such as Salmonella, E. coli, staph, and typhoid-causing bacteria) [42, R].

14) Tongkat Ali May Fight Parasites

In the lab, Tongkat Ali inhibited the growth of Blastocystis sp, a parasite that causes intestinal problems [43].

Another lab study showed that Tongkat Ali inhibited the growth of Toxoplasma gondii, a parasite causing toxoplasmosis [44].

This is likely due to its content of quassinoids, compounds that exhibit anti-parasitic properties by inhibiting parasitic growth, movement, and reproduction [12].

These compounds are also toxic to Plasmodium falciparum, the parasite responsible for malaria [45, 46, 47].

15) Tongkat Ali Has Antiulcer Properties

Tongkat Ali contains quassinoids (eurycomanone and pasakbumin-B), which prevent ulcers by reducing excess stomach acid [9].

Tongkat Ali reduced the severity of alcohol-induced stomach injuries in rats [48].

Other (Anecdotal)

Tongkat Ali is reported to reduce fever, but there are no clinical or animal studies to support this [49].

Supplementing with Tongkat Ali

Limitations and Caveats

Most studies investigating the effects of Tongkat Ali are performed on animals. More human studies are needed to confirm its efficacy.

Although Tongkat Ali is reported to enhance libido and bone health in females, there is no clinical evidence to support this.

Side Effects

Tongkat Ali may cause [50]:

One clinical study showed that doses up to 600 mg/kg of Tongkat Ali did not cause any adverse effects [6].

Another clinical trial also showed that Tongkat Ali had no side effects [5].

However, in the lab, it was found that high doses (equal to or higher than 2.5μg ml) of Tongkat Ali can harm the human sperm [51].

Tongkat Ali herbal coffee is associated with high blood pressure in pregnant women and fetal discomfort [52].

Drug Interactions

Tongkat Ali reduces the absorption of beta blockers (such as propranolol), so these drugs should not be taken with Tongkat Ali [53].

Tongkat Ali inhibits the metabolic activities of CYP1A2, CYP2A6, and CYP2C19 enzymes. These enzymes are part of the CYP540 family, which are responsible for breaking down or activating drugs. Inhibition of these enzymes may cause adverse effects with specific drugs (e.g., some antidepressants, beta-blockers, statins, warfarin, and antiepileptics) [54, 55].

Natural Sources (or Forms of Supplementation)

Tongkat Ali is a herbal supplement available in the form of tablets, water-soluble powder, and coffee [50, 52].


Most clinical trials use 200mg or 400mg of the water-soluble Tongkat Ali extract daily [20, 6, 19, 19].

According to a toxicology report, the acceptable daily dosage for adults is up to 1.2 g/ day [56].

The dosage for children is unknown.

User Experiences

Some users report a boost in libido, energy, and sexual activity, as well as a drop in blood pressure:

“After week 3 I felt a real boost and had a strong increase in my libido and my sexual activity.”

“I felt more energized, my libido improved and my blood pressure dropped.”

“Successfully works as an aphrodisiac.”

“ More energy, strength, and libido. I feel 25 years younger than my age!”

“I’m 56 now, and my libido declined since I was younger. Tongkat Ali made my sex drive back to when I was in my 30s, and my energy levels are higher. However, when I take it late at night I have trouble sleeping.”

Proper use of the product is very effective.”

Other users report an increase in muscle strength and performance:

“At age 60, it gave me longer, stronger, and meatier erections and lots of them. I even get spontaneous erections during the day. My workouts are far more productive and I sleep like a baby.”

“The results in muscle strength and muscle growth are great.”

“The amount of weights that I began to lift in the gym was notable and my strength just seems to triple.”

Some people experienced reduced pain after taking Tongkat Ali:

“Suffer from arthritis and when on naproxen I still had irregular pains in various parts of the body (mainly hands). For over six weeks with Tongkat Ali, feel almost completely pain-free.”

However, others describe Tongkat Ali as not safe and report an enlarged prostate, increase in fat gain, anger, and bad night sweats after taking the herb:

“It’s great if you get the real stuff. But many sources on the web just sell tribulus and put a Tongkat Ali label on the bottle.”

“NOT SAFE!!! It ENLARGED MY PROSTATE for THE REST OF MY LIFE at my 34 YEARS OLD!!!” Still have trouble peeing and I’m terrified of harming my kidneys. Don’t take this supplement.”

“I have more fat on my chest, back, and stomach.”

“This herb has a strong effect when an active dose is taken. I got more sexual thoughts and improved erections. Unfortunately, I also got more angry and aggressive from this herb. It made my testicles swell, with less “shrinkage” at flaccid state, thicker semen, testicular aching, bad night sweats, and increased body hair.”

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