Tongkat Ali (Eurycoma longifolia)
Southeast Asia's most studied testosterone-supporting herb — with real clinical evidence
Also known as: Eurycoma longifolia • Longjack • Malaysian Ginseng • Pasak Bumi
Overview
Tongkat Ali (Eurycoma longifolia) is a flowering plant native to Southeast Asian rainforests, particularly Malaysia and Indonesia. It has been used for centuries in traditional medicine as an energy tonic and aphrodisiac. Modern research has validated many traditional claims, showing that standardized Tongkat Ali extract can increase testosterone levels, improve body composition, reduce cortisol, and enhance male fertility. Unlike many testosterone boosters, Tongkat Ali has a substantial body of human clinical trials. The mechanism involves multiple pathways: it may increase the release of free testosterone from sex hormone-binding globulin (SHBG), support Leydig cell function, reduce cortisol (which suppresses testosterone), and provide antioxidant protection to testicular tissue.
Key Benefits
Testosterone Support
Multiple human trials show Tongkat Ali increases total and free testosterone by 15-37% over 4-12 weeks. A study in stressed adults found 200mg/day increased testosterone by 37% while reducing cortisol by 16%. The mechanism likely involves freeing testosterone from SHBG and supporting Leydig cell function.
Cortisol Reduction & Stress Management
Tongkat Ali has adaptogenic properties, reducing cortisol levels by 16% in stressed individuals. Since cortisol suppresses testosterone production, this cortisol-lowering effect may partly explain the testosterone increase. Users report improved stress resilience and mood.
Body Composition
Through its effects on testosterone and cortisol, Tongkat Ali may improve body composition. Studies show modest increases in lean mass and reductions in body fat percentage over 4-12 weeks, particularly when combined with exercise.
Male Fertility
Tongkat Ali has been shown to improve sperm concentration, motility, and morphology. A study in infertile men found significant improvements in all semen parameters after 9 months of supplementation, with 14.7% of couples achieving spontaneous pregnancy.
Dosage & How to Take
The standard dose is 200-400mg of standardized extract (100:1 or 200:1) daily. Most clinical trials use 200mg/day. Some protocols suggest cycling (5 days on, 2 days off) though this is not well-studied.
| Purpose | Dose | Notes |
|---|---|---|
| Testosterone support | 200-400 mg/day standardized extract | Results typically seen in 4-8 weeks |
| Stress reduction | 200 mg/day | Based on the cortisol/testosterone study |
| Male fertility | 200 mg/day for 3-9 months | Longer duration needed for spermatogenesis cycle |
| Athletic performance | 200-400 mg/day | Combine with exercise for body composition benefits |
Best Time to Take
Take in the morning. Some users report it can be mildly stimulating. Can be taken with or without food.
With or Without Food
Can be taken with or without food. Some people prefer taking with food to reduce any GI discomfort.
Forms & Bioavailability
| Form | Absorption | Best For | Notes |
|---|---|---|---|
| Standardized Hot-Water Extract (100:1) | Good | Most studied form | 100:1 means 100g of root produces 1g of extract. Standardized to eurycomanone content. |
| Standardized Extract (200:1) | Good | Higher concentration | More concentrated extract. Lower dose needed. |
| Raw Root Powder | Lower | Traditional use | Less concentrated, requires higher doses. Extremely bitter taste. |
Side Effects & Safety
Common
- Restlessness or insomnia (if taken late in day)
- Mild GI upset
- Increased body heat
Rare
- Irritability at high doses
- Insomnia
- Elevated heart rate
Contraindications
- Hormone-sensitive cancers (due to testosterone-increasing effects)
- Immune-suppressive therapy (Tongkat Ali may stimulate immune function)
- Pregnancy and breastfeeding
Interactions
May have additive effects; monitor testosterone levels
May have mild blood pressure-lowering effects
May improve insulin sensitivity; monitor blood sugar
Scientific Research
Tongkat Ali and Testosterone/Cortisol
200mg/day for 4 weeks increased testosterone by 37% and reduced cortisol by 16% in moderately stressed adults
Tongkat Ali and Male Fertility
200mg/day for 9 months significantly improved sperm concentration, motility, and morphology in infertile men
Tongkat Ali and Body Composition
100mg/day for 5 weeks increased lean body mass and reduced body fat in combination with exercise
Food Sources
Frequently Asked Questions
Medical Disclaimer
This content is for educational and informational purposes only and is not intended as medical advice. Always consult with a qualified healthcare professional before starting any supplement regimen, especially if you have pre-existing health conditions or are taking medications. The statements on this page have not been evaluated by the Food and Drug Administration.