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Prescription medication — not a dietary supplement
Selegilineis a prescription (or investigational) drug, not a supplement. It is included here for reference because people research and discuss it (often used off-label) — not as a recommendation. Take it only under a qualified clinician's supervision and only as prescribed; do not source it from grey-market vendors, where identity, purity, and dosing are unverified. The evidence below reflects its clinical trials.
What the evidence says
Most Selegiline studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from mixed-quality meta-analyses and randomised trials published 1996–2025 with a typical study size of 18 participants.
Based on 6 studies · 1 meta-analysis · 18 total participants
Confidence
ModerateBy outcome
Selegiline has an evidence score of 3.5/10 — emerging evidence based on 6 indexed studies, including 1 meta-analysis. An MAO-B-inhibitor drug approved for Parkinson's disease and depression, long studied as a longevity/neuroprotection agent. It extended lifespan in some rodent studies (with mixed results across labs), but there is no human longevity evidence, and it carries MAO-inhibitor interaction risks. A prescription drug used off-label, not a supplement. Representative study: PMID 40816452.
The commonly studied dose of Selegiline is Off-label longevity use mirrors low Parkinson's dosing (e.g. ~5 mg/day, kept low to preserve MAO-B selectivity) under a clinician. Approved Parkinson's dose is 5 mg twice daily; the transdermal patch (depression) is dosed differently. Not an approved longevity regimen.. Individual needs vary — start at the lower end of the range and adjust based on how you respond.
Last reviewed June 2026 · evidence from 6 studies · how we score
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
Selegiline (l-deprenyl)
An MAO-B-inhibitor drug approved for Parkinson's disease and depression, long studied as a longevity/neuroprotection agent. It extended lifespan in some rodent studies (with mixed results across labs), but there is no human longevity evidence, and it carries MAO-inhibitor interaction risks. A prescription drug used off-label, not a supplement.
Selegiline has a credible neuroprotective/antioxidant mechanism, and a 2025 meta-analysis of 22 experiments concluded it reproducibly extends lifespan across mammalian species (upgrading the earlier mixed individual-study picture); but there is still no human longevity evidence and it carries MAO-inhibitor interaction risks.
Selegiline (l-deprenyl) is a selective, irreversible inhibitor of monoamine oxidase B (MAO-B) — the enzyme that degrades dopamine in the brain.
It is FDA-approved for Parkinson's disease (oral) and major depression (the Emsam transdermal patch), and it has been one of the longest-standing candidates in 'anti-aging' pharmacology.
Its longevity rationale is several-fold: by inhibiting MAO-B it preserves dopamine and reduces the hydrogen-peroxide generated by dopamine breakdown, and it independently upregulates antioxidant enzymes (superoxide dismutase, catalase) and shows neuroprotective, anti-apoptotic effects in neuronal models.
The historical excitement came from animal lifespan studies — most famously in rats and in aged beagle dogs, where low-dose deprenyl improved survival, cognition, and motor function in several reports.
The honest picture is more tempered: the rodent lifespan results are genuinely mixed across laboratories (some found extension, particularly in females and at low doses; others found no effect or strain/sex dependence), and crucially there is no human trial showing selegiline extends lifespan or healthspan.
As a drug it is generally well tolerated at low doses, but it is still an MAO inhibitor — at higher doses it loses MAO-B selectivity, creating risk of hypertensive (tyramine 'cheese') reactions and serotonin syndrome with serotonergic drugs (SSRIs, meperidine, etc.).
Selegiline is a prescription medication used off-label for longevity/neuroprotection; it is not a dietary supplement. The score reflects a plausible neuroprotective mechanism and mixed animal lifespan data against no human longevity evidence and real MAO-inhibitor interaction risk.
Selegiline irreversibly inhibits monoamine oxidase B, preserving dopamine and reducing the hydrogen peroxide and aldehydes generated by its breakdown.
Independently of MAO inhibition it upregulates superoxide dismutase and catalase, a proposed contributor to its neuroprotective and longevity effects.
Propargylamine activity reduces apoptotic signaling in neuronal models — the basis of its Parkinson's and neuroprotection rationale.
How Selegiline works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
Tap node to isolate • Pinch to zoom • Tap edge for research
Off-label longevity use mirrors low Parkinson's dosing (e.g. ~5 mg/day, kept low to preserve MAO-B selectivity) under a clinician. Approved Parkinson's dose is 5 mg twice daily; the transdermal patch (depression) is dosed differently. Not an approved longevity regimen.
Take with food
| Form | Type |
|---|---|
| 💊Low-dose oral tablet | Recommended |
| 🧴Transdermal patch (Emsam, for depression) | Alternative |
Pharmaceutical selegiline under supervision; rasagiline is a related, more selective MAO-B inhibitor.
Minimum: 12 weeks
Optimal: 52 weeks
Cycling: Not required
Note: Usually morning dosing; keep doses low to preserve MAO-B selectivity and avoid tyramine/serotonergic interactions.
Dose-response data unavailable. The current published research for Selegiline does not provide sufficient dose-specific outcome data to generate reliable dose-response curves.
Refer to the Dosage & Timing section above for recommended dose ranges based on available evidence.
Improved survival, cognition, and motor function in some rodent and aged-dog studies; results are inconsistent across labs and not shown in humans.
Approved benefit in Parkinson's disease via MAO-B inhibition and dopamine preservation.
At higher doses loses MAO-B selectivity — risk of hypertensive 'cheese' reactions and serotonin syndrome with serotonergic drugs.
Avoid — serious serotonin-syndrome risk.
Use caution; keep doses low and MAO-B-selective.
Avoid — not established as safe.
MAO inhibition plus serotonergic agents can cause life-threatening serotonin syndrome — a key contraindication.
At higher doses, loss of MAO-B selectivity risks hypertensive crisis with tyramine-rich foods or stimulants.
Tip: From amphetamine metabolites; dose earlier in the day.
Tip: Take with food; usually transient.
Tip: Avoid high doses, tyramine foods, and serotonergic drugs.
The best time to take Selegiline is in the morning. Take it with food. Often dosed earlier in the day (it has stimulant-like amphetamine metabolites); keep the dose low to stay MAO-B-selective and avoid tyramine reactions.
Selegiline should be used with caution — talk to a healthcare provider before taking it. The most commonly reported side effects are insomnia / stimulation, nausea / dizziness, hypertensive reaction / serotonin syndrome. Use caution if any of these apply to you: Concurrent serotonergic drugs (SSRIs/SNRIs, meperidine, tramadol, dextromethorphan); Pregnancy / breastfeeding; Pheochromocytoma.
A dietary flavonoid with anti-inflammatory effects in the lab. The honest verdict: the only direct human RCTs test PEA-luteolin combinations for post-COVID smell loss — isolated luteolin's anti-inflammatory, allergy, and brain claims rest on mechanism and reviews, not human trials, and its bioavailability is low.