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 is similarly flagged. Sympathomimetic supplements (yohimbe, bitter orange, 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
Additive serotonergic activity
Selegiline is an MAO-B inhibitor used for Parkinson's. Combined with 5-HTP, serotonin can rise to dangerous levels because there is less MAO available to break it down. We treat this as a do-not-combine pair. The combination has caused serotonin syndrome in case reports with other MAO inhibitors.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Selegiline is an MAO-B inhibitor used for Parkinson's. Combined with L-tryptophan, serotonin can rise to dangerous levels because there is less MAO available to break it down. We treat this as a do-not-combine pair. The combination has caused serotonin syndrome in case reports with other MAO inhibitors.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
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.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Selegiline is an MAO-B inhibitor used for Parkinson's. Combined with SAMe, which has its own serotonin-related activity, serotonin can rise to dangerous levels because there is less MAO available to break it down. We treat this as a do-not-combine pair without specialist sign-off.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
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.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Selegiline is an MAO-B inhibitor used for Parkinson's. Combined with St John's Wort, serotonin can rise to dangerous levels because there is less MAO available to break it down. We treat this as a do-not-combine pair.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
MAOI pressor (blood-pressure surge)
Selegiline is a selective MAO-B inhibitor used for Parkinson's. L-Tyrosine is the raw material the body turns into noradrenaline and adrenaline. Combining a catecholamine precursor with an MAO inhibitor can in theory raise blood pressure, and selegiline 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.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
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.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Additive sympathomimetic activity
Yohimbe raises blood pressure and noradrenaline. Combined with selegiline, it can push blood pressure unpredictably high. We would not recommend combining without specialist supervision.
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.
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 methodologyWant this checked across everything you take?
This page checks the pairs you enter. The personalised Distil report goes further:
- the same graded, cited interaction check across your whole stack, not just the pairs you thought to type in
- where your current routine may be leaving you short of your goals
- the evidence-backed compounds worth adding, and the ones worth dropping
It's a paid report: £79, or £49 for the first 25 customers. The interactions check is one section of it, and you can read a real one in full before you buy.
See a real sample reportSomething 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.