Tongkat ali

Tongkat Ali (Eurycoma longifolia Jack): A Comprehensive Reference

1. Identity, Botanical Classification, and Natural Source

Eurycoma longifolia (commonly called Tongkat Ali, Malaysian ginseng, or long jack) is a flowering plant in the family Simaroubaceae, native to Indochina — including Cambodia, Laos, Malaysia, Myanmar, Thailand, and Vietnam — and to Indonesia (the islands of Borneo and Sumatra), but has also been found in the Philippines. The plant is a medium-sized slender shrub that can reach 10 m (33 ft) in height, and is often unbranched.

Tongkat Ali is an evergreen slow-growing herbal plant that completely matures after 25 years and can be harvested only after 5 years of cultivation. It is popularly known as the "king of herbs" and locally recognized as "Tongkat Ali," which literally means "Ali's walking stick" — a name derived from its long, twisted roots.

The plant is known by a range of names across the region. In Indonesia it is called Pasak Bumi; in Vietnam, Cây Bá Bệnh; in Thailand, it is referred to as Plali. In South-East Asia, it is also known as "Malaysian ginseng." In Malaysia, Eurycoma longifolia is known primarily for its aphrodisiac properties and is called Tongkat Ali by the Malay ethnic group due to the resemblance of the twisted roots to a walking stick.

Plant Parts Used

The leaves, roots, and bark of the plant have been used extensively in traditional medicine for many conditions. The bark is mostly used as a vermifuge, while the taproots are used to treat high blood pressure, malaria, boils, diarrhea, wounds, dysentery, and fever. The leaves are used for washing itches, while the fruits are used in curing dysentery by indigenous people. In commercial preparations, the root and root extract predominate.

Commercial Forms and Preparations

Tongkat Ali is commonly sold in the form of a powder, extract, drink, or capsule. Products list this ingredient either alone or in combination with other ingredients such as Tribulus terrestris, Fadogia agrestis, horny goat weed, ginseng, and L-arginine. The majority of published human supplementation trials have been conducted on specific hot-water-extracts of Eurycoma longifolia — which is the traditional Malaysian preparation — produced using a patented extraction process to isolate and concentrate the bioactive compounds.

Most studies in the scientific literature utilize a commercial, freeze-dried water extract of E. longifolia root standardized to 0.8–1.5% eurycomanone. The characteristic components of one well-studied standardized extract are glycosaponins (40–65%) and eurycomanone (0.8–1.5%); it can also contain canthin-6-one alkaloids and isoscopoletin (coumarin).

2. Traditional and Historical Use

The root has been used in traditional medicine in Southeast Asia over centuries. Eurycoma longifolia is among the most popular traditional folk medicines extensively used particularly in Malaysia, Indonesia, Thailand, Laos, Cambodia, and Vietnam for its pharmacological properties.

Tongkat Ali — also known as Akar Ali — has been used as a traditional herbal medicine for centuries by the indigenous people (also known as Orang Asli) in Malaysia. The traditional approach of drinking boiled freshly-cut roots is widely practiced, and it has been used as an aphrodisiac, antibiotic, appetite stimulant, and to promote general well-being.

The plant parts have been traditionally used for their antimalarial, aphrodisiac, anti-diabetic, antimicrobial, and anti-pyretic activities. The plant is also used traditionally by local folks for the treatment of other ailments such as bleeding, cough, fever, antimalarial treatment, ulcers, high blood pressure, and fevers.

Tongkat Ali has been a central part of jamu, an ancient Malay medicinal practice and remedy, drawing on similar traditional culture from Indonesia. For centuries, different parts of the plant have been used as a natural remedy to treat fever, hypertension, or sexual insufficiency.

Eurycoma longifolia Jack, a small Simaroubaceae tree, is popularly used as a sexual tonic in traditional medicine for aphrodisiac activity and improvement of fertility and male libido. Traditional preparation primarily involved boiling the roots to produce a decoction. The root of Tongkat Ali is typically boiled and consumed as a decoction or incorporated into traditional herbal formulas.

Regulatory status in the region reflects this long tradition. Tongkat Ali is categorized as traditional medicine by the Ministry of Health Malaysia, and its approved use is regulated by the National Pharmaceutical Regulatory Agency (NPRA).

3. Key Constituents and Active Compounds

E. longifolia, predominantly the roots, contains active constituents including quassinoids, quassinoid diterpenoids, canthin-6-one alkaloids, β-carboline alkaloids, squalene derivatives, triterpene-type tirucallane, tirucallane-type triterpenes, laurycolactone, and bioactive steroids.

Quassinoids

Derivatives of quassinoids — a group of physiologically active diterpenoids — are further classified as eurycomanones, eurycomanols, eurycomalactones, eurycolactones, eurycomanosl, and eurycomaosides. The most pharmacologically significant quassinoid in Tongkat Ali is eurycomanone, which is typically used as the marker compound for extract standardization. Other notable quassinoids include eurycomanol, eurycomalactone, and 13-alpha(21)-epoxyeurycomanone.

These molecules have shown inhibitory functions in vivo and in vitro, particularly anti-inflammatory, anti-viral, anti-malarial, and anti-proliferative activities.

Alkaloids

The plant is also reported to consist of various types of important bioactive compounds including quassinoids, canthine-6-one alkaloids, triterpenes, squalene derivatives, and β-carboline alkaloids, which are mostly found in the root part. Alkaloids and triterpenes act as antioxidants and may play an important role in counteracting oxidative stress and reducing bone loss.

Eurypeptides (Polypeptides)

Polypeptides (eurypeptides) are known to improve energy status and sex drive in animal studies and may enhance the biosynthesis of various androgens. Eurypeptides may also work by stimulating dehydroepiandrosterone (DHEA) and alleviating sex-hormone binding globulin (SHBG), thus subsequently increasing free testosterone levels.

Glycosaponins

Glycosaponins constitute a substantial fraction of standardized water extracts. The characteristic components of the most widely studied novel food extract are glycosaponins (40–65%) and eurycomanone (0.8–1.5%).

4. Mechanisms of Action

Multiple mechanisms have been proposed to explain Tongkat Ali's observed biological effects, primarily in relation to androgens and the stress hormone axis. These mechanisms are based largely on in vitro and animal data, with some human evidence.

Testosterone Production via the HPG Axis

Eurycomanone, the highest concentrated quassinoid in the root extract of E. longifolia, improved fertility by increasing testosterone and spermatogenesis of rats through the hypothalamus-pituitary-gonadal (HPG) axis, but the mechanisms underlying the effects are not totally clear. In a more recent study, E. longifolia root extract induced testosterone synthesis along with an increase in LH and FSH but decreased estrogen levels, providing evidence that the extract may potentially down-regulate the estrogen-mediated feedback effect on LH and FSH secretion in the HPG axis.

Aromatase and Phosphodiesterase Inhibition

Eurycomanone inhibits phosphodiesterase and aromatase, thus inhibiting the conversion of testosterone to oestrogen, leading to the enhanced production of testosterone by the Leydig cell explants.

Sex Hormone-Binding Globulin (SHBG) Modulation

Sex hormone-binding globulin (SHBG) is a protein produced by the liver that binds to testosterone, rendering it biologically inactive. Only "free" (unbound) testosterone can interact with androgen receptors in tissues throughout the body. Several studies have demonstrated a testosterone-boosting effect that might be caused by the release of free testosterone from the sex-hormone-binding globulin.

Cortisol and the HPA Axis

Tongkat Ali, used for centuries in traditional medicine systems of Southeast Asia for treating lethargy, low libido, depression, and fatigue, appears to have significant potential for restoring hormone balance (cortisol/testosterone) and improving psychological mood state in humans exposed to various modern stressors, including aging, dieting, and exercise stress.

Pharmacokinetics

Analysis of pharmacokinetic profile revealed that E. longifolia exhibits higher bioavailability, a high volume of distribution, a slow elimination rate, and does not show inhibitory effects on cytochrome P450 (CYP) isoenzymes.

5. Scientific Evidence by Area of Use

5.1 Testosterone and Male Hypogonadism

This is the area with the most clinical study data for Tongkat Ali.

Systematic Review and Meta-Analysis (2022): A systematic review and meta-analysis was conducted according to PRISMA guidelines, with a literature search performed across PubMed, Scopus, Web of Science, Cochrane, Ovid/Embase, and Google Scholar, to identify clinical trials investigating the use of E. longifolia extraction as a sole intervention in adult males and reporting pre- and post-treatment serum testosterone as an outcome. This 2022 systematic review and meta-analysis of 9 studies (including 5 RCTs) published in Medicina found a statistically significant improvement in total testosterone across both healthy volunteers and hypogonadal men (SMD = 1.352, p = 0.001).

Late-Onset Hypogonadism Trial (published in Andrologia, 2012): 76 of 320 patients suffering from late-onset hypogonadism (LOH) were given 200 mg of a standardised water-soluble extract of Tongkat Ali for 1 month. The Ageing Males' Symptoms (AMS) score and serum testosterone concentration were measured. Results showed that treatment significantly improved the AMS score as well as the serum testosterone concentration (P < 0.0001). Before treatment, only 10.5% of the patients showed no complaints on the AMS scale and 35.5% had normal testosterone levels; after treatment, 71.7% and 90.8% of patients showed normal values, respectively.

Effects in Men with Androgen Deficiency Alongside Training (Randomized, Double-Blind, Placebo-Controlled Study): A study of 45 men with age-related androgen deficiency who took 200 mg of Tongkat Ali daily, alongside training, had higher overall testosterone levels.

Evidence Strength: Tongkat Ali is known for its aphrodisiac and pro-fertility effects and is promoted as a "testosterone booster," and while some evidence exists for this effect in men with low testosterone and the mechanisms are plausible, the data are not convincing. Research shows testosterone optimization is the most evidence-supported application of Tongkat Ali, with clinical data stronger than that of most other herbal testosterone supplements; effects are most pronounced in men with suboptimal baseline testosterone, including those with late-onset hypogonadism and age-related hormonal decline. Overall, the evidence is preliminary but directionally consistent for men with clinically low or borderline testosterone; evidence in eugonadal (normal testosterone) men is considerably weaker.

5.2 Stress, Mood, and Cortisol

Randomized, Placebo-Controlled Trial (Talbott et al., 2013, published in the Journal of the International Society of Sports Nutrition): Stress hormones and mood state were assessed in 63 subjects (32 men and 31 women) screened for moderate stress and supplemented with a standardized hot-water extract of TA root or placebo for 4 weeks. Significant improvements were found in the TA group for Tension (−11%), Anger (−12%), and Confusion (−15%). Stress hormone profile (salivary cortisol and testosterone) was significantly improved by TA supplementation, with reduced cortisol exposure (−16%) and increased testosterone status (+37%).

The current study found that daily supplementation with tongkat ali root extract (200 mg/day) improves stress hormone profile (lower cortisol; higher testosterone) and certain mood state parameters (lower tension, anger, and confusion). Typical dosage recommendations, based on traditional use and on the available scientific evidence in humans including dieters and athletes, call for 50–200 mg/day of a water-extracted tongkat ali root standardized to 22% eurypeptides.

Evidence Strength: Moderate — at least one well-designed, placebo-controlled human trial supports cortisol-lowering and mood effects, but the study is relatively small (n = 63) and short-term (4 weeks). Replication in larger, independent trials is needed.

5.3 Sexual Health — Libido and Erectile Function

Some studies in animals and humans suggest that tongkat ali might increase testosterone levels and improve aspects of sexual health such as male fertility, erectile dysfunction, and libido. Tongkat Ali may modestly help erectile function and libido based on limited short human trials, typically at 200 to 400 mg of standardized extract for 8 to 12 weeks.

Evidence Strength: The evidence for libido and erectile function is based on small, short-term trials and is considered preliminary. Modern research has focused on tongkat ali's potential effects on testosterone levels, athletic performance, and sexual health, but it is important to know that evidence is limited and sometimes mixed; many studies have been small or short-term.

5.4 Male Fertility and Sperm Parameters

One study found that men with infertility due to an unknown cause experienced significant improvements in various measures of sperm quality — such as sperm count, motility, and morphology — after supplementing with 200 mg of tongkat ali extract for nine months, and this improvement in sperm quality led to spontaneous pregnancies in 11 of the 75 participants.

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

The root of Tongkat Ali is believed to have androgenic properties that regulate spermatogenesis through androgen hormonal pathways, improving overall sperm quality by increasing sperm count (sperm concentration), sperm motility, and sperm morphology.

Evidence Strength: Limited but directionally positive. Although promising, larger randomized trials are still needed. Most studies in this area have been small or conducted in men with unexplained infertility without adequate controls.

5.5 Athletic Performance and Body Composition

Today, Eurycoma longifolia preparations are commercially available and advertised to enhance athletic performance and muscle strength.

Tongkat Ali contains compounds called quassinoids including eurycomaoside, eurycolactone, and eurycomanone, which may help the body use energy more efficiently, reduce fatigue, and improve endurance. A 2014 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.

However, a 2024 study that assessed the effects of taking 400 mg of tongkat ali daily did not improve body composition in exercise-trained males and females. These conflicting results suggest that tongkat ali may exhibit some ergogenic effects, depending on the dose and length of treatment, but more research is necessary to better understand this.

In a study with cyclists, cyclists taking tongkat ali showed 32% lower cortisol and 16% higher testosterone compared to placebo, which aligns with the idea that the herb helps maintain hormonal balance under physical and psychological stress.

Evidence Strength: A few studies suggest that tongkat ali might increase muscle strength in men. Studies to date have reported no beneficial effects of tongkat ali on endurance performance. Overall, studies have been small and short-term in length, and more high-quality research is needed to confirm any beneficial effects.

5.6 Antimalarial Properties

Quassinoids, the compounds isolated from the stems of E. longifolia, showed positive antimalarial properties against in vitro culture of chloroquine-resistant Plasmodium falciparum. Eurycoma longifolia or Tongkat Ali has the potential to be utilised as an antimicrobial and antiparasitic agent that correlates with its traditional use to treat jaundice, malaria, and many more.

Evidence Strength: Evidence is confined to in vitro and animal studies. No human clinical trials evaluating Eurycoma longifolia as an antimalarial treatment have been published. This remains a preclinical area of interest.

5.7 Anticancer Properties

E. longifolia root extract was mostly reported to exhibit anticancer properties using different human cancerous cell lines, particularly breast cancer cells. Quassinoid molecules have shown inhibitory functions in vivo and in vitro, particularly anti-inflammatory, anti-viral, anti-malarial, and anti-proliferative activities.

Evidence Strength: Entirely preclinical (in vitro and animal data). No human clinical evidence supports anticancer use. This area remains in early-stage research.

5.8 Bone Health

Animal studies, cited in the Examine.com research database, have examined the relationship between Tongkat Ali and bone structure, particularly in the context of androgen deficiency. There is a body of animal research examining Eurycoma longifolia as a potential medicinal plant in the prevention and treatment of male osteoporosis due to androgen deficiency. However, no human clinical trials specifically examining bone mineral density endpoints have been published. Evidence in this area is preclinical only.

6. Dosage Forms and Doses Reported in Studies

The following dosages are those reported in published research and should not be interpreted as universal recommendations:

• 200 mg/day of a standardised water-soluble extract for 1 month was used in the late-onset hypogonadism trial (76 patients).
• 200 mg/day (standardized hot-water extract) for 4 weeks was used in the stress hormone and mood study (63 subjects, mixed sex).
• 400 mg/day was used in a 2014 study in 25 active older adults examining muscular strength.
• 200 mg/day for nine months was used in the unexplained male infertility trial (75 participants).
• Typical dosage recommendations based on traditional use and available human evidence call for 50–200 mg/day of a water-extracted tongkat ali root standardized to 22% eurypeptides.
• The novel food application assessed by EFSA proposed use as a food supplement in amounts up to 200 mg/day.
• Studies using a dosage of 200–600 mg/day in humans have noted minor side effects, including gastrointestinal symptoms and itching.

Most of the studies in the published literature utilize the same commercial, freeze-dried water extract of E. longifolia root standardized to 0.8–1.5% eurycomanone. Comparisons across trials are therefore complicated by differences in extract type, standardization level, and dosing regimen.

7. Safety Considerations and Known Interactions

7.1 General Short-Term Tolerability

Short-term clinical trials (up to six months) consistently report that standardized tongkat ali extract at typical doses is well tolerated. Studies using a dosage of 200–600 mg/day in humans have noted minor side effects, including gastrointestinal symptoms and itching; otherwise, adverse effects seem to be rare.

7.2 Animal Toxicology

In rodent toxicology studies, neither mutagenicity nor clastogenicity was noted, and acute oral LD50 was more than 6 g/kg body weight. After 4-week subacute and 13-week subchronic exposure paradigms at doses of 0, 0.6, 1.2, and 2 g/kg body weight per day, adverse effects attributable to the test compound were not observed with respect to body weight, hematology, serum biochemistry, urinalysis, macropathology, or histopathology. However, pathological changes in the liver were observed in rats at a dose of 1,200 mg/kg, corresponding to approximately a 1,200 mg daily dose in humans.

7.3 EFSA Genotoxicity Concern

The EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) issued an opinion in 2021 on the safety of Eurycoma longifolia root extract as a novel food. The analysis expressed concern that the herbal supplement induced evidence of DNA damage and concluded that its "safety has not been established under any condition of use."

More specifically, according to the 2021 EFSA report, a high dose (2,000 mg/kilogram body weight) of the water-based extract from dried ground tongkat ali may lead to DNA damage of stomach and duodenum tissues, and because tongkat ali has the potential to cause DNA damage, the panel concluded that the safety of any condition of its use has not been established. The EFSA Panel noted positive results from a submitted in vitro chromosome aberration test, which indicates clastogenic properties of the novel food extract.

7.4 Liver Injury

Reports of clinically apparent liver injury attributed to tongkat ali in bodybuilders have recently appeared. A 2024 case report published in Cureus documented drug-induced liver injury (DILI) associated with Tongkat Ali use in the context of the rising popularity of herbal and dietary supplements. A major review notes that there are no available reports on the side effects of long-term use and no standards for purity of the plant extract or specific chemical component responsible for its activity.

7.5 Heavy Metal Contamination

Products containing tongkat ali have been reported to be contaminated with heavy metals (such as lead and mercury) or adulterated with sildenafil (a prescription drug used to treat erectile dysfunction). In a study analyzing 100 products in various pharmaceutical dosage forms of tongkat Ali hitam preparations found in Malaysia, results showed that 26% of these products possessed 0.53–2.35 ppm of mercury, and therefore did not comply with the quality requirement for traditional medicines in Malaysia. Some studies have raised concerns about the possible contamination of herbal preparations of tongkat ali by heavy metals in Malaysia, including levels of lead and mercury above permissible limits.

7.6 Populations for Which Data Are Lacking

Due to a lack of data in these populations, Tongkat Ali is not advised for use by males with diabetes, heart disease, kidney illness, liver disease, sleep apnea, or by pregnant or nursing women, or children (per Turck et al., 2021). The EFSA novel food assessment specified the target population as the adult population, excluding pregnant and lactating women.

7.7 Drug Interactions

Minor side effects have been reported in humans, but overall adverse effects appear to be rare, and Tongkat Ali may interact with certain medications like propranolol. Propranolol is a drug used to treat hypertension; however, Tongkat Ali may hinder its effects by preventing its absorption and bioavailability. Pharmacokinetic analysis indicates that E. longifolia does not show inhibitory effects on cytochrome P450 (CYP) isoenzymes, though this finding requires further confirmation in human studies.

7.8 Long-Term Safety Data Gap

More evidence is needed to confirm any marketed benefits of tongkat ali. The safety of tongkat ali in humans has not been fully established. Even though toxicity and safety evaluation studies have been pursued, a major gap still exists in providing scientific basis for the commercial utilization and clearance of Tongkat Ali products with regard to consumer safety. There is sparse safety, quality, and toxicity data available for tongkat ali from human studies, along with a lack of standard criteria and regulation for its commercial preparations.

References

• Bhat R, Karim AA. Tongkat Ali (Eurycoma longifolia Jack): a review on its ethnobotany and pharmacological importance. Fitoterapia. 2010;81:669-79. PubMed PMID: 20434529
• Tambi MI, Imran MK, Henkel RR. Standardised water-soluble extract of Eurycoma longifolia, Tongkat ali, as testosterone booster for managing men with late-onset hypogonadism. Andrologia. 2012;44 Suppl 1:226-30. PubMed PMID: 21671978
• Talbott SM, et al. Effect of Tongkat Ali on stress hormones and psychological mood state in moderately stressed subjects. J Int Soc Sports Nutr. 2013;10:28. PubMed PMID: 23705671
• Leisegang K, Finelli R, Engel KM, et al. Eurycoma longifolia (Jack) Improves Serum Total Testosterone in Men: A Systematic Review and Meta-Analysis of Clinical Trials. Medicina (Kaunas). 2022;58(8):1047. PMC9415500
• EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA); Turck D, et al. Safety of Eurycoma longifolia (Tongkat Ali) root extract as a novel food pursuant to Regulation (EU) 2015/2283. EFSA J. 2021;19:e06937. PMC8693240
• Tongkat Ali. In: LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. National Library of Medicine / NCBI Bookshelf. NBK609015
• Low BS, et al. Eurycomanone, the major quassinoid in Eurycoma longifolia root extract increases spermatogenesis by inhibiting the activity of phosphodiesterase and aromatase in steroidogenesis. J Ethnopharmacol. 2013;149(1):201-207. PubMed PMID: 23810842
• Ismail SB, et al. Effect of Eurycoma longifolia standardised aqueous root extract–Physta® on testosterone levels and quality of life in ageing male subjects: a randomised, double-blind, placebo-controlled multicentre study. Clin Phytosci. 2021. PMC8254464
• Evaluation of Acute 13-Week Subchronic Toxicity and Genotoxicity of the Powdered Root of Tongkat Ali (Eurycoma longifolia Jack). Evid Based Complement Alternat Med. 2013. PMC3767077
• Latip MQA, et al. A Systematic Review on Antimicrobial and Antiparasitic Activity of Eurycoma longifolia Jack (Tongkat Ali). Biomed Res Int. 2022;2022:4999797. PMC9279065
• Ulbricht C, et al. An evidence-based systematic review of tongkat ali (Eurycoma longifolia) by the Natural Standard Research Collaboration. J Diet Suppl. 2013;10(1):54-83. PubMed PMID: 23419023
• Kaliounji A, et al. A Rare Case of Tongkat Ali-Induced Liver Injury: A Case Report. Cureus. 2024;16(3):e56639. PMC11032125
• Ang HH, Lee EL. Contamination of mercury in tongkat Ali hitam herbal preparations. Food Chem Toxicol. 2006;44(8):1245-1247. PubMed PMID: 16567029
• U.S. Department of Defense — Operation Supplement Safety (OPSS). Tongkat Ali: Uses and Safety in Dietary Supplements.
• Examine.com. Research Breakdown on Tongkat Ali (Eurycoma longifolia).
• Wikipedia. Eurycoma longifolia.
• Tongkat Ali (Eurycoma longifolia): a possible therapeutic candidate against Blastocystis sp. PMC4476169
• Segaran et al. A narrative review on pharmacological significance of Eurycoma longifolia jack roots. Longhua Chinese Medicine. 2021.
• Henkel RR, et al. Effect of Eurycoma longifolia Jack (Tongkat ali) extract on human spermatozoa in vitro. Andrologia. 2014;46:1-10. PubMed PMID: 22332826