Tongkat Ali (Eurycoma longifolia)

Overview

Tongkat Ali (scientific name Eurycoma longifolia Jack) is a fast‑growing tropical shrub native to Southeast Asia. Its root has been used for centuries as a traditional “adaptogen” and male‑health tonic. Modern research focuses on its capacity to modulate endocrine function, especially testosterone production, and to support physical performance and stress resilience.

Benefits

Hormonal balance & testosterone: Randomized, double‑blind trials (e.g., 300 mg daily for 12 weeks) have shown modest increases in total testosterone and improvements in luteinizing‑hormone levels, supporting male fertility and libido.
Physical performance & muscle strength: Meta‑analyses of 5‑8 week interventions report 5‑10 % gains in lean body mass and enhanced sprint power, likely linked to androgenic effects and reduced cortisol.
Stress & mood: Standardized extracts (200–400 mg) reduce perceived stress and improve mood scores in healthy adults, possibly via modulation of the hypothalamic‑pituitary‑adrenal (HPA) axis.
Cognitive function: Small pilot studies show improved short‑term memory and mental fatigue after 4–6 weeks of supplementation, likely mediated by increased neurosteroid synthesis.
Metabolic health: Limited evidence suggests modest improvements in insulin sensitivity and lipid profile in overweight men, though data remain preliminary.

How It Works

Bioactivity: Tongkat Ali’s bioactivity stems primarily from quassinoid‑type eurycomanone, eurycomanol, and related alkaloids.
Selective Androgen Receptor Modulation: These compounds act as selective androgen‑receptor modulators and corticosteroid‑binding protein inhibitors.
Increased Free Testosterone: This increases free testosterone by reducing sex‑hormone‑binding globulin (SHBG) and inhibiting aromatase activity.
HPA Axis Downregulation: The extracts down‑regulate the HPA axis, decreasing cortisol release.
Skeletal Muscle Effects: In skeletal muscle, they activate the PI3K/Akt/mTOR pathway, enhancing protein synthesis and inhibiting myostatin.
Brain Effects: In the brain, increased neurosteroid (DHEA‑S) production supports neuronal excitability and reduces oxidative stress.
Combined Effects: The combined endocrine and signaling effects underlie the observed improvements in strength, mood, and metabolic parameters.

Dosage

Standardized Extracts: Typical clinical trials use standardized root extracts (≥ 20 % eurycomanone).
Common Dosage Range: The most common dose range is 200–400 mg per day.
Administration: Taken in divided doses (e.g., 100 mg morning + 100 mg evening) with food to improve absorption.
Muscle Building/Athletic Performance: For muscle‑building or athletic performance, 300 mg/day for 8–12 weeks is common.
Stress Relief: For stress‑relief a lower 200 mg/day may suffice.
Cycling: Cycling (e.g., 5 days on, 2 days off) is often recommended to prevent tolerance.
Individual Considerations: Individuals with low baseline testosterone may benefit from the higher end of the range, while older adults or those on hormone‑sensitive conditions should start at 200 mg and monitor response.
Consistency: Consistency for at least 4 weeks is needed to observe hormonal changes.

Safety & Side Effects

General Tolerance: Tongkat Ali is generally well‑tolerated at ≤ 400 mg/day.
Side Effects: Reported side‑effects are mild: insomnia, irritability, or increased heart rate in sensitive individuals.
Contraindications: Contra-indications include prostate cancer, breast cancer, or other hormone‑sensitive malignancies due to its androgen‑enhancing properties.
Potential Drug Interactions:
- Anticoagulants (e.g., warfarin): Possible additive effect on platelet function.
- Antidiabetic agents: May augment hypoglycaemic effect.
- Stimulants: Possible synergistic increase in heart rate or blood pressure.
Avoidance: Pregnant or lactating women, children, and individuals with severe cardiovascular disease should avoid supplementation.
Long-Term Safety: Long-term (>12 weeks) safety data are limited; periodic monitoring of testosterone, liver enzymes, and blood pressure is advisable.

Chemistry

Active Compound: The principal active compound, eurycomanone, is a quassinoid with the formula C₂₀H₂₈O₈ (M.W. 376.44 g/mol).
IUPAC Name: (2R,3R,4R,5S,6R,7S,8S,9S,10R,11R,12R,13R,14S,15S,16S,17R)-2,5,7‑trihydroxy‑3‑acetyl‑11‑(2‑hydroxy‑3‑methyl‑but-1‑enyl)‑13‑methoxy‑3,4‑dihydro‑2,5‑dihydroxy‑6‑[2‑(2‑hydroxy‑3‑methyl‑but‑1‑enyl)‑3‑hydroxy‑1‑oxopropyl]‑7,12‑dihydroxy‑13‑oxobicyclo[13.2.0]‑pentadecane‑6‑yl acetate.
Structure: It contains a furan‑type ring, multiple hydroxyl groups, and a lactone‑like carbonyl, giving it moderate lipophilicity (logP ≈ 2.8).
Antioxidant Activity: The C‑20 quinone‑type structure confers strong antioxidant activity.
Extract Quantification: Standardized extracts are typically quantified by high‑performance liquid chromatography (HPLC) to ensure ≥ 20 % eurycomanone content.

Sources & Quality

Cultivation: Eurycoma longifolia is cultivated mainly in Malaysia, Indonesia, and Thailand.
Harvesting: Mature roots (≥ 5 years) are harvested.
Sustainable Sourcing: Sustainable sourcing involves controlled‑growth plantations to avoid over‑harvesting wild populations.
Extraction Methods: Extraction commonly employs 70 % ethanol or water‑ethanol mixtures followed by spray‑drying to produce a powdered extract; supercritical CO₂ extraction is emerging for higher purity.
Quality Control: Quality control standards include HPLC‑based quantification of eurycomanone, absence of heavy metals (< 10 ppm lead), and microbial limits (≤ 10⁴ CFU/g).
Certifications: Certified organic or GMP‑certified manufacturers are preferred to minimize pesticide residues.
Batch Consistency: Batch‑to‑batch consistency is crucial; look for third‑party testing (e.g., USP, NSF) on label claims.