Supplements and Selegiline.
Selegiline, sold under the brand name Eldepryl, is a selective MAO-B inhibitor used in Parkinson disease.
Selegiline is a selective MAO-B inhibitor. It is used in Parkinson disease for symptomatic management and a possible effect on disease progression (selegiline, rasagiline, safinamide). MAO-B selectivity means less of the dietary tyramine concern that defines the older MAOIs. But selectivity scales inversely with dose. At higher doses the agents lose some of their B selectivity, and the MAOI class precautions begin to apply. The supplement surface that matters is serotonergic. 5-HTP combined with selegiline or rasagiline carries serotonin syndrome concern in case reports, and is the closest match for an inferred exclusion. St John's Wort and rhodiola are similarly flagged. Sympathomimetic supplements (yohimbe, bitter orange, panax ginseng, caffeine at high doses) carry care given the underlying mechanism. Other Parkinson medicines (levodopa, dopamine agonists) often run alongside an MAO-B inhibitor. Supplement decisions are best routed through the neurology team rather than community pharmacy.
Below are the 9 documented pairs we have explicitly assessed against Selegiline in the Distil database: 6 red and 3 amber. The pairs cluster around 3 mechanisms: Additive serotonergic activity, MAOI pressor (blood-pressure surge), and Additive sympathomimetic activity. Every call is cited to either a clinical reference (PMID) or the British National Formulary. Anything not on this list is either still to be assessed or beyond our database scope. The checker beneath surfaces assessments by supplement, and the missing-item form at the bottom of the page routes any uncatalogued supplement 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 serotonergic activity
Red Does 5-HTP interact with ?
Taking 5-HTP with selegiline (an MAO-B inhibitor used for Parkinson's) can push serotonin to dangerous levels, because there is less MAO available to break it down, so we treat this as a do-not-combine pair. The combination has caused serotonin syndrome in case reports with other MAO inhibitors.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Red Does L-Tryptophan interact with ?
Taking L-tryptophan with selegiline (an MAO-B inhibitor used for Parkinson's) can push serotonin to dangerous levels, because there is less MAO available to break it down, so we treat this as a do-not-combine pair. The combination has caused serotonin syndrome in case reports with other MAO inhibitors.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Red Does Rhodiola Rosea interact with ?
Selegiline is an MAO-B inhibitor used for Parkinson's, and rhodiola appears to slow monoamine oxidase too. Stacking them could push serotonin too high, risking serotonin syndrome. We treat this as a do-not-combine pair without specialist sign-off.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Red Does SAMe interact with ?
Taking SAMe with selegiline (an MAO-B inhibitor used for Parkinson's) can push serotonin to dangerous levels, because SAMe has its own serotonin-related activity and there is less MAO available to break it down, so we treat this as a do-not-combine pair without specialist sign-off.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Red Does Saffron Extract interact with ?
Selegiline is an MAO-B inhibitor used for Parkinson's, and saffron has its own antidepressant effect that appears to act on serotonin. Combined, serotonin can rise too high because there is less of the enzyme available to break it down, risking serotonin syndrome. We treat this as a do-not-combine pair without specialist sign-off.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Red Does St John's Wort interact with ?
Taking St John's Wort with selegiline (an MAO-B inhibitor used for Parkinson's) can push serotonin to dangerous levels, because there is less MAO available to break it down, so we treat this as a do-not-combine pair.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
MAOI pressor (blood-pressure surge)
Amber Does L-Tyrosine interact with ?
Taking L-Tyrosine with selegiline can in theory raise blood pressure, because tyrosine is the raw material the body turns into noradrenaline and adrenaline and selegiline is an MAO-B inhibitor that can add its own pressor effect at higher doses. Raise this with your prescriber and have blood pressure checked rather than starting on your own.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does Panax Ginseng interact with ?
Ginseng has been reported to clash with the older MAOI phenelzine. Selegiline is a more selective MAOI, so the concern is weaker, but ginseng's mild stimulant-like effects could still add up. If you take selegiline, check with the doctor who prescribed it before starting ginseng.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Additive sympathomimetic activity
Amber Does Yohimbe interact with ?
Yohimbe raises blood pressure and noradrenaline. Combined with selegiline, it can push blood pressure unpredictably high. We would not recommend combining without specialist supervision.
Evidence: Limited human data, based on case reports and a known mechanism.
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 (food-supplement interactions only; for drug-drug interactions, the BNF is authoritative). Use the checker below to surface any supplement, and submit a missing item if you take something we have not catalogued.
No affiliates. No commission. We earn nothing on what you buy.
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.
£49 introductory price for early customers. Standard price £79.
Something missing?
If a supplement or medication you take isn't in our autocomplete, tell us. We go through what people flag every week and add what's missing.