Eurycoma longifolia (Tongkat Ali): Uses, Dosage, and Buying Tips

Eurycoma longifolia, often called Tongkat Ali or longjack, is a Southeast Asian root used traditionally for libido, energy, and recovery. People take it as capsules, powders, or tinctures. Below I cover what the research shows, common doses, safety warnings, and how to choose a good supplement.

What the research says, dosage, and safety

Small clinical trials report that Tongkat Ali can raise free testosterone and boost libido in men with low levels. Other studies link it to reduced stress and slight improvements in strength when combined with training. Most trials run 4–12 weeks with tens to a few hundred participants, so evidence looks promising but limited.

Common doses used in research are about 200–400 mg per day of a standardized extract or 1–2 grams of raw root powder daily. Products sometimes list extract ratios (for example 100:1); that describes concentration but not quality. Start at a low dose and give a trial of 4–12 weeks to judge effects.

Most people tolerate it well, but side effects include restlessness, insomnia, irritability, and faster heartbeat. Avoid if you have hormone-sensitive cancer, or if you are pregnant or breastfeeding. Tongkat Ali can lower blood sugar and may interact with diabetes drugs or blood thinners, so talk to your doctor if you take medications.

How to pick and use a quality product

Look for clear labeling: species name Eurycoma longifolia, part used (root), extract ratio, and any standardized marker. Prefer brands with third-party lab testing or Certificates of Analysis. Minimal fillers and a transparent manufacturer address are good signs. If a product promises instant dramatic gains, treat it with skepticism.

Forms vary: whole root powder is closest to traditional use, while concentrated extracts aim to deliver the same compounds in a smaller dose. Extract ratios (for example 50:1 or 100:1) show how much raw root it takes to make the extract, but they don’t tell you the active compound amount. Ask the maker if they test for quassinoids or eurycomanone, compounds often measured in studies. Prefer products that publish a Certificate of Analysis showing actual marker levels.

Expect gradual changes, not miracles. Some men notice better libido within two weeks; others need the full 8–12 weeks. Athletes may see slight strength gains when combining Tongkat Ali with a structured resistance program and adequate protein. Avoid stacking with other stimulants until you know your tolerance. Consider cycling supplements—use for 8–12 weeks then take a break for several weeks—so your body doesn’t adapt.

Check country of origin. Wild-harvested roots can be overexploited; prefer cultivated root and brands with third-party testing to reduce risk.

Want brand picks or a short checklist to evaluate supplements? I can send a concise list with lab-report links and red flags to avoid.