Tongkat Ali and medications.
Tongkat Ali is in the Distil supplement database, evidence Grade B/C. The page below lists every medication we have explicitly assessed it against.
Tongkat Ali, also called Eurycoma longifolia or longjack, is taken at 200 to 400mg a day of standardised extract, with the Physta brand carrying the best evidence. It is used for testosterone support, libido, cortisol reduction and stress, but the honest framing matters: the Grade B to C evidence is mostly in men with low-normal or stress-suppressed testosterone, not healthy men with normal levels, and the effect size is modest. Trials show normalised testosterone in hypogonadal men and reduced cortisol with higher testosterone in stressed subjects. Two practical cautions stand out. Unregulated products have been found contaminated with heavy metals, so a certified brand is important. There is also a single 2025 case report of new-onset atrial flutter in an older man after starting it, so anyone with arrhythmia, palpitations or unexplained dizziness should avoid it pending more evidence and flag any heart symptoms to a GP. It may also interact with immunosuppressants. Worthwhile only with realistic expectations and a trusted source.
Below are the 3 documented pairs we have explicitly assessed for Tongkat Ali: 3 amber. The pairs cluster around 2 mechanisms: Additive androgenic effect and Androgen-raising vs androgen-lowering (opposing). Every call is cited to either a clinical reference (PMID) or the British National Formulary. Anything not listed here is either still to be assessed or beyond our database scope. The checker beneath surfaces assessments by medication, and the missing-item form at the bottom of the page routes any uncatalogued medication into our next curation pass.
Documented interactions
Last reviewed 14 June 2026. Each interaction below lists the evidence its assessment drew on: some rest on studies of the exact pair, others on mechanism evidence, where a citation may support one part of the reasoning rather than the exact combination. The evidence line on each entry says which.
Additive androgenic effect
Amber Does interact with Testosterone?
Tongkat ali can modestly raise the body's own testosterone, so taking it alongside prescribed testosterone may add to that effect. If you are on testosterone replacement, mention this supplement to the prescriber who monitors your levels before combining them.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Androgen-raising vs androgen-lowering (opposing)
Amber Does interact with Dutasteride?
Dutasteride works by lowering a potent form of testosterone. Tongkat ali tends to raise the body's testosterone, so in theory it could work against what dutasteride is doing. If you take dutasteride for prostate symptoms, it is worth discussing this supplement with your prescriber.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does interact with Finasteride?
Finasteride works by lowering a potent form of testosterone. Tongkat ali tends to raise the body's testosterone, so in theory it could work against what finasteride is doing. If you take finasteride for hair loss or prostate symptoms, it is worth discussing this supplement with your prescriber.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
What this list does not say. Pairs not flagged here are not implicitly safe. They are either not yet in our database, or fall outside our inclusion scope. Use the checker below to surface any medication, and submit a missing item if you take something we have not catalogued.
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How we grade severity, choose what's in scope, and what we exclude.
Every call on this page is reasoned. We publish the full rubric for severity tiers, the medication inclusion logic, the evidence grades we accept, and what we deliberately leave out. About three thousand words. Worth reading once if you use this tool more than occasionally.
Read the full methodologyA full supplement review, built around you, not a generic stack.
The free checker answers one interaction question at a time. A Distil report reviews the bigger picture: your goals, diet, medications, current supplements and any blood results you provide, then shows what appears worth keeping, changing, adding or leaving out.
- what your diet already covers, so you are not adding a capsule for something food is already handling
- which evidence-graded compounds are worth considering for your goals, and which were considered but left out
- what to keep, change or stop from what you already take, plus the order to introduce anything new
- how your medications and complete supplement stack fit together, with daily timing and a clear point for reassessment
The interaction check is one section of the full report. You also get the reasoning behind each recommendation and the evidence references used.
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