The Complete Science-Based Guide to Tongkat Ali: Benefits, Human Studies, and Dosing Protocols

Tongkat Ali (Eurycoma longifolia Jack), also known as "Longjack" or "Malaysian Ginseng," has emerged as one of the most scientifically validated natural testosterone-supporting supplements available today. Unlike many herbal supplements that rely primarily on animal research or anecdotal reports, Tongkat Ali boasts an impressive and growing body of human clinical trials demonstrating real, measurable benefits for testosterone levels, sexual health, stress reduction, and physical performance.

For over 2,000 years, this flowering shrubby tree native to Southeast Asia has been used in traditional medicine systems across Malaysia, Indonesia, Vietnam, and Thailand. Modern research has now validated many of these traditional uses, particularly for male sexual health and vitality.

This comprehensive guide examines everything currently known about Tongkat Ali, including detailed human studies, mechanism of action, optimal dosing protocols, safety considerations, and stacking strategies with other supplements.

Tongkat Ali: Benefits

What is Tongkat Ali?

Botanical Profile

Scientific name: Eurycoma longifolia Jack

Family: Simaroubaceae

Common names: Tongkat Ali (Malay), Longjack (English), Pasak Bumi (Indonesian), Cay Ba Binh (Vietnamese)

Part used: Primarily the roots

Native habitat: Malaysia, Indonesia, Thailand, Vietnam, Laos, and other Southeast Asian countries

Tongkat Ali is a slow-growing, flowering tree that can reach heights of 15 meters (approximately 50 feet) in tropical rainforests. The roots, which can extend several meters underground, are the primary source of the medicinal compounds used in supplements.

Active Compounds

The therapeutic effects of Tongkat Ali are attributed to a complex mixture of bioactive compounds:

Quassinoids (bitter compounds):

• Eurycomanone (the most studied)

• Eurycomanol

• Eurycolactone

• Eurylactone

• 13α(21)-epoxyeurycomanone

Alkaloids:

• β-carboline alkaloids

• Canthin-6-one alkaloids

Other compounds:

• Eurypeptides (bioactive glycopeptides with 36 amino acids)

• Polysaccharides

• Flavonoids

• Triterpenes

The standardization of Tongkat Ali extracts typically focuses on eurycomanone content (ranging from 0.8% to 2.5%) and total polysaccharides (22-40%), depending on the extraction method used.

Mechanisms of Action: How Tongkat Ali Works

Understanding how Tongkat Ali exerts its effects helps explain both its benefits and its safety profile.

1. Stimulation of Luteinizing Hormone (LH) Release

Tongkat Ali's primary mechanism involves stimulating the release of luteinizing hormone from the pituitary gland. LH then signals the Leydig cells in the testes to produce more testosterone. This is fundamentally different from taking exogenous testosterone or prohormones.

Key advantage: Because Tongkat Ali works by stimulating your body's natural testosterone production pathways rather than replacing them, it doesn't suppress the hypothalamic-pituitary-gonadal (HPG) axis. This means:

• No shutdown of natural production

• No testicular atrophy

• No need for post-cycle therapy (PCT)

• Hormonal feedback loops remain intact

2. Aromatase Inhibition

Some studies suggest Tongkat Ali may possess mild aromatase-inhibiting properties. Aromatase is the enzyme that converts testosterone to estradiol (estrogen). By inhibiting this enzyme, more testosterone remains available in its active form rather than being converted to estrogen.

However, interestingly, one human study found that while testosterone increased significantly, estradiol also increased by 30%. This suggests the mechanism may be more nuanced than simple aromatase inhibition.

3. Reduction of Sex Hormone-Binding Globulin (SHBG)

SHBG is a protein that binds to testosterone, making it unavailable for use by tissues. Tongkat Ali has been shown in some studies to reduce SHBG levels, thereby increasing the proportion of free testosterone the biologically active form.

A study in physically active seniors found that while total testosterone increased, the more dramatic effect was on free testosterone due to significant declines in SHBG concentrations, particularly in women.

4. Cortisol Reduction

Cortisol, the primary stress hormone, has an inverse relationship with testosterone when one goes up, the other typically goes down. Tongkat Ali has demonstrated consistent ability to reduce cortisol levels.

In one study of moderately stressed individuals, Tongkat Ali supplementation resulted in:

• 16% reduction in cortisol exposure

• Improved testosterone-to-cortisol ratio

• Reduced tension, anger, and confusion

This cortisol-lowering effect may partially explain the testosterone-boosting benefits, as reducing cortisol creates a more favorable hormonal environment for testosterone production.

5. Enhanced Steroidogenic Enzyme Expression

Animal and in vitro studies suggest that Tongkat Ali may enhance the expression and activity of enzymes involved in testosterone biosynthesis, including:

• CYP11A1 (cholesterol side-chain cleavage enzyme)

• CYP17A1 (17α-hydroxylase/17,20-lyase)

• 3β-HSD (3β-hydroxysteroid dehydrogenase)

• StAR (steroidogenic acute regulatory protein)

These enzymes are critical for converting cholesterol into testosterone through a series of biochemical steps.

6. Antioxidant and Anti-inflammatory Effects

Tongkat Ali contains compounds that act as powerful antioxidants, fighting cellular damage from free radicals. This antioxidant activity may protect Leydig cells (testosterone-producing cells) from oxidative stress, maintaining their function as we age.

Human Clinical Studies: The Evidence Base

Unlike many supplements that rely heavily on animal research, Tongkat Ali has been extensively studied in humans. Here's a comprehensive review of the most significant clinical trials.

Testosterone Studies

Study #1: The Comprehensive Dose-Response Trial (2021)

Design: Randomized, double-blind, placebo-controlled trial

Participants: 105 men aged 40-65 years

Intervention: Daily supplementation with either placebo or 100 mg, 200 mg, or 400 mg of Tongkat Ali extract for 12 weeks

Primary outcomes: Testosterone levels, muscle strength, sexual function

Results:

• 100 mg group: Total testosterone increased from baseline by a mean of 11%

• 200 mg group: Total testosterone increased by 37% (from approximately 320 ng/dL to 440 ng/dL)

• 400 mg group: Total testosterone increased but not significantly more than 200 mg

• Free testosterone and DHEA also increased significantly

• Muscle strength: Only the 200 mg dose significantly increased Back-Leg-Chest (BLC) dynamometer strength

• Quality of life: Significant improvements in aging male symptoms (fatigue, vigor, energy)

Key Finding: The 200 mg dose appeared optimal, higher doses didn't produce additional benefits, suggesting a ceiling effect.

Study #2: The Stressed Population Trial (2013)

Design: Randomized, double-blind, placebo-controlled

Participants: 63 men and women (32 men, 31 women) with moderate stress

Intervention: 200 mg daily of standardized Tongkat Ali extract for 4 weeks

Outcomes: Stress hormones, mood states

Results:

• Cortisol: 16% reduction in salivary cortisol exposure

• Testosterone status: Increased by 37%

• Mood improvements:

  • Tension reduced by 11%

  • Anger reduced by 12%

  • Confusion reduced by 15%

• Overall: Significant improvement in stress hormone profile

Significance: This was one of the first studies to demonstrate Tongkat Ali's stress-reducing properties and its ability to improve the testosterone-to-cortisol ratio.

Study #3: The Young Men Study (2021)

Design: Randomized, double-blind, placebo-controlled, matched-pair

Participants: 32 healthy young men (mean age 24.4 ± 4.7 years

Intervention: 600 mg daily for 2 weeks

Outcomes: Testosterone, free testosterone, SHBG, LH, estrogen, FSH

Results:

• Total testosterone: Increased by 15%

• Free testosterone: Increased by 34%

• Estradiol: Increased by 30% (interesting finding)

• LH, FSH, SHBG: No significant changes

Key Insight: This study demonstrated that Tongkat Ali can boost testosterone even in healthy young men with normal baseline levels not just in those with low testosterone. The mechanism appears to involve both the HPG and HPA (hypothalamic-pituitary-adrenal) axes.

Study #4: The Elderly Athletes Trial (2013)

Design: Open-label trial

Participants: 13 physically active male and 12 physically active female seniors (aged 57-72 years)

Intervention: 400 mg daily Tongkat Ali extract for 5 weeks

Outcomes: Hormones, muscle strength, body composition

Results:

• Men: Significant increases in total testosterone, free testosterone, and DHEA

• Women: Significant increases in total testosterone (primarily due to reduced SHBG) and free testosterone

• Both sexes: Significant increases in muscular force (handgrip strength)

• Body composition: Improvements in lean body mass

Significance: Demonstrated benefits extend to both men and women, and to older populations.

Study #5: The Androgen Deficiency Study (2021)

Design: 6-month randomized, double-blind, placebo-controlled, four-arm clinical trial

Participants: 45 men with androgen deficiency of aging males (ADAM), mean age 47.38 ± 5.03 years

Groups:

• G1: Control + placebo

• G2: Control + 200 mg Tongkat Ali

• G3: Concurrent training + placebo

• G4: Concurrent training + 200 mg Tongkat Ali

Results:

• Erectile function: Improvements in both Tongkat Ali and exercise groups

• Best results: Concurrent training + Tongkat Ali group showed the most significant improvements

• Total testosterone: Increased in groups receiving Tongkat Ali

• Combination effect: Synergy between exercise and Tongkat Ali supplementation

Clinical Implication: For men with age-related androgen deficiency, combining 200 mg Tongkat Ali with structured exercise produces superior results compared to either intervention alone.

Sexual Health and Fertility Studies

Male Infertility and Semen Quality

Study: Published in Evidence-Based Complementary and Alternative Medicine (2012)

Participants: 75 men with idiopathic infertility or oligospermia

Intervention: 200 mg daily Tongkat Ali for 3 months

Results:

• Significant improvement in semen volume

• Increased sperm concentration

• Enhanced sperm motility

• Improved sperm morphology

• Higher pregnancy rates in partners

Mechanism: The improvements likely resulted from increased testosterone and LH levels supporting spermatogenesis.

Erectile Dysfunction

Multiple studies have examined Tongkat Ali's effects on erectile function:

Systematic Review and Meta-Analysis (2015):

• Analyzed multiple RCTs on erectile function

• Conclusion: Tongkat Ali significantly improves erectile function compared to placebo

• Effect size was moderate to large

• Safety profile was excellent with no serious adverse events

Body Composition and Athletic Performance Studies

Study #1: The Exercise-Trained Population (2024)

Design: Randomized, double-blind, placebo-controlled

Participants: 33 exercise-trained males and females (mean age 33.1 ± 13.0 years)

Intervention: 400 mg daily Tongkat Ali for 4 weeks

Measurements: Body composition, salivary testosterone, handgrip strength, sleep quality

Results:

• Surprising finding: No significant changes in body composition

• Testosterone: No significant changes in salivary free testosterone

• Cortisol: No significant changes

• Interpretation: In already-trained individuals with presumably normal testosterone levels and low stress, Tongkat Ali may not provide additional measurable benefits in the short term (4 weeks)

Important Context: This study highlights that Tongkat Ali appears most effective for:

• Individuals with low or suboptimal testosterone

• Those under significant stress

• Older individuals experiencing age-related decline

• Sedentary individuals beginning exercise programs

Study #2: Muscle Strength and Endurance

Design: Multiple studies examining physical performance

Key Findings:

• Increased grip strength in elderly populations

• Improved Back-Leg-Chest strength measurements

• Enhanced endurance in some studies

• Reduced muscle damage markers after exercise

• Faster recovery between training sessions

Meta-Analyses and Systematic Reviews

Comprehensive Review (2022)

Title: "Eurycoma longifolia (Jack) Improves Serum Total Testosterone in Men: A Systematic Review and Meta-Analysis of Clinical Trials"

Published: Medicina (2022)

Analysis: 9 randomized controlled trials included

Conclusions:

Significant increase in total testosterone levels following Tongkat Ali treatment

• Benefits observed in both healthy volunteers and men with hypogonadism

• Effect sizes ranged from small to large depending on baseline testosterone levels

• Most pronounced effects in those with initially low testosterone

• Excellent safety profile across all studies

Dose-Response Relationship:

• Effective doses ranged from 100-600 mg daily

• Duration of supplementation: 4-12 weeks optimal

• Longer supplementation periods (up to 6 months) showed sustained benefits

Benefits of Tongkat Ali: Evidence Summary

1. Testosterone Enhancement

Evidence Level: Strong (multiple RCTs, meta-analyses)

Expected increases:

• Total testosterone: 15-37% increase from baseline

• Free testosterone: 34-61% increase

• DHEA: Significant increases observed

• Testosterone/cortisol ratio: Improved significantly

Who benefits most:

• Men aged 40+ with declining testosterone

• Individuals with stress-related low testosterone

• Those with mild to moderate hypogonadism

• Post-exercise testosterone recovery

Who benefits least:

• Young men (under 30) with optimal testosterone

• Well-trained athletes already at physiological peaks

• Those taking exogenous testosterone replacement

2. Sexual Health Improvements

Evidence Level: Strong to Moderate

Demonstrated benefits:

• Erectile function: Significant improvements in multiple studies

• Libido: Enhanced sexual desire and interest

• Sexual performance: Improved satisfaction scores

• Ejaculatory function: Better control and satisfaction

• Orgasm quality: Enhanced in some reports

Clinical relevance: Tongkat Ali may serve as a natural alternative or complement to pharmaceutical ED treatments for mild to moderate cases.

3. Male Fertility Enhancement

Evidence Level: Moderate to Strong

Semen parameter improvements:

• Sperm concentration: +18-25% increase

• Sperm motility: Progressive motility improved

• Sperm morphology: More normal forms

• Semen volume: Increased

• Overall fertility potential: Enhanced

Clinical success: Higher pregnancy rates observed in partners of men supplementing with Tongkat Ali.

4. Stress Reduction and Mood Enhancement

Evidence Level: Moderate (limited studies but consistent results)

Psychological benefits:

• Reduced perceived stress

• Lower anxiety levels

• Decreased tension and anger

• Reduced confusion and mental fatigue

• Improved sense of well-being

• Better mood stability

Mechanism: Primarily through cortisol reduction and improved hormonal balance.

5. Physical Performance and Body Composition

Evidence Level: Mixed (variable results depending on population)

Muscle strength:

• Increased grip strength (especially elderly)

• Enhanced lower body strength

• Improved overall muscular force

Body composition:

• Modest increases in lean body mass (elderly populations)

• Potential fat mass reduction (limited evidence)

• Better muscle-to-fat ratio in some studies

Athletic performance:

• Possibly enhanced recovery

• Reduced markers of muscle damage

• Improved training tolerance

Reality check: Effects are modest and most pronounced in:

• Older individuals

• Deconditioned/sedentary starting exercise

• Those with low baseline testosterone

Well-trained athletes show minimal body composition changes in short-term studies.

6. Energy and Fatigue Reduction

Evidence Level: Moderate

Reported benefits:

• Increased daily energy levels

• Reduced chronic fatigue

• Improved vitality scores

• Better physical and mental stamina

• Enhanced motivation

Mechanism: Likely multi-factorial involving testosterone increases, cortisol reduction, and improved sleep quality.

7. Bone Health (Emerging Evidence)

Evidence Level: Preliminary (mostly animal studies)

Potential benefits:

• Enhanced bone mineral density

• Improved osteoblast activity

• Protection against age-related bone loss

Clinical relevance: Given testosterone's important role in bone health, Tongkat Ali's testosterone-boosting effects may translate to bone benefits, but this requires more human research.

8. Cognitive Function (Limited Evidence)

Evidence Level: Weak (few human studies)

Possible benefits:

• Reduced brain fog

• Improved focus and concentration

• Enhanced mental clarity

• Better cognitive performance under stress

Note: Most evidence is anecdotal or from animal studies. More human research needed.

9. Immune Function Support

Evidence Level: Preliminary

Mechanisms:

• Immunomodulatory properties

• Enhanced antibody production

• Improved lymphocyte activity

• Anti-inflammatory effects

Clinical significance: Testosterone plays a role in immune function, so maintaining healthy levels may support overall immunity.

Optimal Dosing Protocols

Based on the comprehensive review of human studies, here are evidence-based dosing recommendations:

Standard Dosing Guidelines

For Testosterone Support and General Health:

• Dose: 200-400 mg daily of standardized extract

• Timing: Once daily, preferably with food

• Duration: Minimum 4-12 weeks for full effects

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For Older Men (50+ years) with Low Testosterone:

• Starting dose: 200 mg daily

• Maintenance: 200-400 mg daily

• Duration: Can be used long-term (up to 6 months studied)

• Monitoring: Consider baseline and follow-up testosterone testing

For Athletic Performance/Body Composition:

• Dose: 400 mg daily

• Timing: Can split into 200 mg twice daily

• Duration: 8-12 weeks, potentially cycled

• Combination: Works best with structured training program

For Stress Management:

• Dose: 200 mg daily

• Duration: 4 weeks minimum

• Timing: Morning or early afternoon (to avoid evening cortisol disruption)

For Fertility Enhancement:

• Dose: 200-300 mg daily

• Duration: Minimum 3 months (one full spermatogenic cycle)

• Combination: Best results with lifestyle optimization (diet, exercise, sleep)

Dosing Considerations

Body Weight Adjustment: While not explicitly studied, some practitioners recommend adjusting based on body weight:

• Under 70 kg (154 lbs): 200 mg daily

• 70-90 kg (154-198 lbs): 300 mg daily

• Over 90 kg (198 lbs): 400 mg daily

Age-Based Recommendations:

• Under 30: Generally not recommended unless specific medical indication

• 30-40: 200 mg if experiencing symptoms of low testosterone

• 40-50: 200-300 mg for maintenance

• 50+: 300-400 mg for optimal benefits

Timing Strategies:

Option 1: Single Daily Dose

• Take 200-400 mg once daily with breakfast or lunch

• Advantages: Convenience, good compliance

• Disadvantages: May cause single peak rather than sustained levels

Option 2: Split Dosing

• Take 200 mg twice daily (breakfast and dinner)

• Advantages: More stable blood levels, may enhance effects

• Disadvantages: Requires remembering twice daily

With or Without Food:

• Most studies administered with or after meals

• May reduce potential mild gastrointestinal discomfort

• Absorption appears adequate with food

Cycling Protocols

Is Cycling Necessary?

Unlike anabolic steroids or prohormones, Tongkat Ali doesn't shut down natural testosterone production, so cycling isn't physiologically necessary. However, some practitioners recommend cycling for theoretical reasons:

Continuous Use Protocol:

• 12 weeks on

• Continue indefinitely if benefits are maintained and no side effects occur

• Supported by 6-month human study showing safety and sustained benefits

Conservative Cycling Protocol:

• 8-12 weeks on

• 2-4 weeks off

• Repeat as needed

• Rationale: Periodic breaks may maintain sensitivity to the herb

Performance Cycling Protocol (for athletes):

• 8 weeks on during training/competition phases

• 2-4 weeks off during deload/recovery phases

• Can align with training periodization

Special Populations

Women:

• Dose: 100-200 mg daily (lower than men)

• Benefits: Improved free testosterone, libido, energy, muscle tone

• Safety: Well-tolerated in female studies

• Caution: Not recommended during pregnancy or lactation

Athletes Subject to Drug Testing:

• Tongkat Ali is NOT banned by WADA

• It works through natural testosterone production, not exogenous hormones

• Should not affect testosterone/epitestosterone ratio testing

• Choose third-party tested products to avoid contamination

Safety Profile and Side Effects

One of Tongkat Ali's most attractive features is its excellent safety profile, particularly when compared to pharmaceutical testosterone replacement or prohormones.

Clinical Safety Data

Human Studies Safety Summary: Across numerous human trials involving hundreds of participants:

• No serious adverse events reported

• No clinically significant changes in liver enzymes (ALT, AST, ALP)

• No kidney function impairment (creatinine, BUN)

• No cardiovascular concerns (blood pressure, heart rate)

• No hematological abnormalities

• No hormonal shutdown or testicular atrophy

Toxicology Studies:

Acute Toxicity (single dose):

• LD50 in mice: >3,000 mg/kg for water extract

• LD50 in mice: 1,500-2,000 mg/kg for alcohol extract

• Translation: Extremely high safety margin for human doses

Subchronic Toxicity (13 weeks):

• NOAEL (No Observed Adverse Effect Level): 2,000 mg/kg in rats

• Equivalent human dose: Up to 1,200 mg daily for 60 kg adult

• 12 times higher than typical supplementation doses

• Acceptable Daily Intake (ADI): Up to 1,200 mg for adults

Long-term Safety:

• 6-month human study: No adverse effects at 200 mg daily

• Long-term users (>1 year): No reported chronic health issues in follow-up surveys

• Cytoprotective effects observed (reduced markers of liver/kidney stress)

Reported Side Effects

Common (but mild and infrequent):

• Gastrointestinal discomfort (2-3% of users)

  • Mild nausea

  • Bloating

  • Stomach upset

• Insomnia (if taken late in the day)

• Mild headache (rare)

• Skin itching (rare, approximately 1%)

Very Rare but Reported:

• Elevated body temperature (thermogenic effect in sensitive individuals)

• Restlessness or jitteriness (particularly at higher doses >600 mg)

• Increased heart rate (uncommon)

Serious Adverse Events: There have been isolated case reports of:

• Liver injury: A few case reports exist of cholestatic liver injury in bodybuilders

• Important context: These cases often involved:

  • Multiple supplements simultaneously

  • Contaminated or adulterated products

  • Extremely high doses (>1,000 mg daily)

  • Alcohol-based extracts rather than water extracts

  • Use of products not third-party tested

Product Quality Concerns

The Adulteration Problem: Like many herbal supplements, the Tongkat Ali market has quality control issues:

• Some products contain little to no actual Tongkat Ali

• Contamination with heavy metals (lead, mercury, arsenic) in low-quality sources

• Adulteration with synthetic compounds (rare but documented)

• Mislabeling of extract ratios and concentrations

Quality Indicators:

• Certificate of Analysis

• Standardization to specific eurycomanone or eurypeptide content

• GMP-certified manufacturing

  
  

Contraindications and Precautions

Absolute Contraindications (Do Not Use):

• Pregnancy

• Breastfeeding

• Children and adolescents (under 18)

• Hormone-sensitive cancers (prostate, breast)

• Active liver disease (hepatitis, cirrhosis)

Relative Contraindications (Use with Caution/Medical Supervision):

• Diabetes (may affect blood sugar)

• Heart disease (due to potential cardiovascular stimulation)

• Sleep apnea (testosterone can worsen in some cases)

• Kidney disease (theoretical concern)

• Hypertension (monitor blood pressure)

• Benign prostatic hyperplasia (BPH) - effects unclear

Recommendation: Always inform your healthcare provider about Tongkat Ali use, especially if taking prescription medications.

Long-Term Safety Considerations

What We Know:

• 6-month human study showed no adverse effects

• Traditional use spans centuries

• Anecdotal reports of multi-year use without problems

• Animal studies up to 13 weeks show protective effects

What We Don't Know:

• Effects of continuous use beyond 6 months (no formal studies)

• Decades-long safety profile

• Impact on specific at-risk populations

• Interactions with all medications

Prudent Approach:

• Regular health monitoring if using long-term

• Periodic liver function tests (baseline and annually)

• Testosterone level monitoring

• Prostate health screening for men over 50 (PSA, DRE)

• Discontinue if any concerning symptoms develop

Conclusion: The Tongkat Ali Verdict

Unlike many supplements that overpromise and underdeliver, Tongkat Ali stands out as one of the few natural testosterone-supporting compounds with legitimate scientific backing.

What We Know with Confidence

Proven Benefits:

• ✓ Increases testosterone 15-37% in men with normal to low levels

• ✓ Enhances free testosterone significantly (30-60% increases)

• ✓ Reduces cortisol and improves stress response

• ✓ Improves erectile function and sexual health

• ✓ Enhances sperm parameters in infertile men

• ✓ Increases muscle strength, especially in older adults

• ✓ Excellent safety profile at therapeutic doses (200-600 mg)

• ✓ Does not suppress natural testosterone production

• ✓ No need for post-cycle therapy

Who Benefits Most:

• Men 40+ with declining testosterone

• Individuals under chronic stress

• Those with mild hypogonadism

• Men with sexual dysfunction or fertility issues

• Older adults seeking to maintain vitality

• Athletes looking for natural performance support

Who May Not Need It:

• Young men (<30) with optimal testosterone

• Those already on testosterone replacement therapy

• Women (though safe, limited research)

• Individuals with hormone-sensitive conditions

The Bottom Line

Tongkat Ali represents one of the most scientifically credible natural approaches to supporting healthy testosterone levels. With multiple human clinical trials, established safety, and consistent benefits for sexual health, stress reduction, and physical performance, it earns its place among evidence-based supplements.

However, Tongkat Ali is not a miracle cure or replacement for fundamental lifestyle factors. It works best as part of a comprehensive approach including:

• Progressive resistance training

• Adequate protein intake (1.6-2.2 g/kg body weight)

• Quality sleep (7-9 hours nightly)

• Stress management

• Healthy body composition

• Micronutrient sufficiency

For men experiencing age-related testosterone decline, chronic stress, or sexual health concerns, Tongkat Ali offers a safe, natural alternative to pharmaceutical interventions or a complement to comprehensive medical treatment under physician supervision.

This article is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional before starting any supplement regimen. Tongkat Ali should not be used as a replacement for medical treatment of diagnosed hypogonadism without physician guidance.

References

Human Clinical Studies on Testosterone and Hormones

1. George A, Suzuki N, Abas AB, et al. Immunomodulation in middle-aged humans via the ingestion of Physta® standardized root water extract of Eurycoma longifolia Jack—A randomized, double-blind, placebo-controlled, parallel study. Phytother Res. 2016;30(4):627-635. doi:10.1002/ptr.5571

2. Henkel RR, Wang R, Bassett SH, et al. Tongkat Ali as a potential herbal supplement for physically active male and female seniors—a pilot study. Phytother Res. 2014;28(4):544-550. doi:10.1002/ptr.5017

3. Tambi MIIM, 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):226-230. doi:10.1111/j.1439-0272.2011.01168.x

4. Talbott SM, Talbott JA, George A, Pugh M. Effect of Tongkat Ali on stress hormones and psychological mood state in moderately stressed subjects. J Int Soc Sports Nutr. 2013;10:28. doi:10.1186/1550-2783-10-28

5. Chan KQ, Stewart C, Chester N, Hamzah SH, Yusof A. The effect of Eurycoma longifolia on the regulation of reproductive hormones in young males. Andrologia. 2021;53(4):e14001. doi:10.1111/and.14001

6. Leisegang K, Finelli R, Sikka SC, Panner Selvam MK. Eurycoma longifolia (Jack) Improves serum total testosterone in men: A systematic review and meta-analysis of clinical trials. Medicina (Kaunas). 2022;58(8):1047. doi:10.3390/medicina58081047

7. Rehman SU, Choe K, Yoo HH. Review on a traditional herbal medicine, Eurycoma longifolia Jack (Tongkat Ali): Its traditional uses, chemistry, evidence-based pharmacology and toxicology. Molecules. 2016;21(3):331. doi:10.3390/molecules21030331

8. George A, Henkel R. Phytoandrogenic properties of Eurycoma longifolia as natural alternative to testosterone replacement therapy. Andrologia. 2014;46(7):708-721. doi:10.1111/and.12214

Sexual Health and Fertility Studies

9. Tambi MI, Imran MK. Eurycoma longifolia Jack in managing idiopathic male infertility. Asian J Androl. 2010;12(3):376-380. doi:10.1038/aja.2010.7

10. Ismail SB, Wan Mohammad WM, George A, et al. Randomized clinical trial on the use of PHYSTA freeze-dried water extract of Eurycoma longifolia for the improvement of quality of life and sexual well-being in men. Evid Based Complement Alternat Med. 2012;2012:429268. doi:10.1155/2012/429268

11. Kotirum S, Ismail SB, Chaiyakunapruk N. Efficacy of Tongkat Ali (Eurycoma longifolia) on erectile function improvement: systematic review and meta-analysis of randomized controlled trials. Complement Ther Med. 2015;23(5):693-698. doi:10.1016/j.ctim.2015.07.009

12. Udani JK, George AA, Musthapa M, Pakdaman MN, Abas A. Effects of a proprietary freeze-dried water extract of Eurycoma longifolia (Physta) and Polygonum minus on sexual performance and well-being in men: a randomized, double-blind, placebo-controlled study. Evid Based Complement Alternat Med. 2014;2014:179529. doi:10.1155/2014/179529

Body Composition and Athletic Performance Studies

13. Hamzah S, Yusof A. The ergogenic effects of Tongkat Ali (Eurycoma longifolia): a pilot study. Br J Sports Med. 2003;37(5):465-466. doi:10.1136/bjsm.37.5.465

14. Chen CK, Mohamad WMZW, Ooi FK, Ismail SB, Abdullah MR, George A. Supplementation of Eurycoma longifolia Jack extract for 6 weeks does not affect urinary testosterone: epitestosterone ratio, liver and renal functions in male recreational athletes. Int J Prev Med. 2014;5(6):728-733. PMID:24949023

15. George A, Udani J, Zainal Abidin N, Yusof A. Efficacy and safety of Eurycoma longifolia (Physta®) water extract plus multivitamins on quality of life, mood and stress: a randomized placebo-controlled and parallel study. Food Nutr Res. 2018;62. doi:10.29219/fnr.v62.1374

Animal and In Vitro Studies

16. Solomon MC, Erasmus N, Henkel RR. In vivo effects of Eurycoma longifolia Jack (Tongkat Ali) extract on reproductive functions in the rat. Andrologia. 2014;46(4):339-348. doi:10.1111/and.12082

17. Erasmus N, Solomon MC, Fortuin KA, Henkel RR. Effect of Eurycoma longifolia Jack (Tongkat ali) extract on human spermatozoa in vitro. Andrologia. 2012;44(5):308-314. doi:10.1111/j.1439-0272.2011.01175.x

18. Chan KL, Low BS, Teh CH, Das PK. The effect of Eurycoma longifolia on sperm quality of male rats. Nat Prod Commun. 2009;4(10):1331-1336. PMID:19911566

19. Wahab NA, Mokhtar NM, Halim WN, Das S. The effect of Eurycoma longifolia Jack on spermatogenesis in estrogen-treated rats. Clinics (Sao Paulo). 2010;65(1):93-98. doi:10.1590/s1807-59322010000100013

Toxicology and Safety Studies

20. Shuid AN, Siang LK, Chin TG, Muhammad N, Mohamed N, Soelaiman IN. Acute and subacute toxicity studies of Eurycoma longifolia in male rats. Int J Pharmacol. 2011;7(5):641-646. doi:10.3923/ijp.2011.641.646

21. Salman SA, Amrah SS, Wahab MS, et al. Modification of propranolol's bioavailability by Eurycoma longifolia water-based extract. J Clin Pharm Ther. 2010;35(6):691-696. doi:10.1111/j.1365-2710.2009.01141.x

22. Abdul Razak HS, Shuid AN, Naina Mohamed I. Combined effects of Eurycoma longifolia and testosterone on androgen-deficient osteoporosis in a male rat model. Evid Based Complement Alternat Med. 2012;2012:872406. doi:10.1155/2012/872406

23. Low BS, Das PK, Chan KL. Standardized quassinoid-rich Eurycoma longifolia extract improved spermatogenesis and fertility in male rats via the hypothalamic-pituitary-gonadal axis. J Ethnopharmacol. 2013;145(3):706-714. doi:10.1016/j.jep.2012.11.043

Reviews and Meta-Analyses

24. Thu HE, Mohamed IN, Hussain Z, Jayusman PA, Shuid AN. Eurycoma longifolia as a potential adoptogen of male sexual health: a systematic review on clinical studies. Chin J Nat Med. 2017;15(1):71-80. doi:10.1016/S1875-5364(17)30010-9

25. Bhat R, Karim AA. Tongkat Ali (Eurycoma longifolia Jack): a review on its ethnobotany and pharmacological importance. Fitoterapia. 2010;81(7):669-679. doi:10.1016/j.fitote.2010.01.011

26. Ulbricht C, Conquer J, Flanagan K, 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. doi:10.3109/19390211.2012.761467

Additional Research on Mechanisms and Chemistry

27. Tada H, Yasuda F, Otani K, Doteuchi M, Ishihara Y, Shiro M. New antiulcer quassinoids from Eurycoma longifolia. Eur J Med Chem. 1991;26(3):345-349. doi:10.1016/0223-5234(91)90069-O

28. Ang HH, Cheang HS. Studies on the anxiolytic activity of Eurycoma longifolia Jack roots in mice. Jpn J Pharmacol. 1999;79(4):497-500. doi:10.1254/jjp.79.497

29. Ang HH, Sim MK. Eurycoma longifolia Jack enhances libido in sexually experienced male rats. Exp Anim. 1997;46(4):287-290. doi:10.1538/expanim.46.287

30. Zanoli P, Zavatti M, Montanari C, Baraldi M. Influence of Eurycoma longifolia on the copulatory activity of sexually sluggish and impotent male rats. J Ethnopharmacol. 2009;126(2):308-313. doi:10.1016/j.jep.2009.08.021