Is MAOIs (e.g., Phenelzine, Tranylcypromine) Safe with 5-HTP?
Free · No account · based on published sources including NIH ODS, FDA drug labels, and peer-reviewed literature
This combination is contraindicated. Never take 5-HTP if you are currently prescribed or have recently discontinued an MAOI antidepressant. Allow a minimum 14-day washout period after stopping an MAOI before considering 5-HTP.
Why this interaction occurs
MAOIs inhibit monoamine oxidase, the primary enzyme responsible for breaking down serotonin. Adding 5-HTP dramatically increases serotonin synthesis, creating a dangerous accumulation that can cause severe or fatal serotonin toxicity with rapid onset.
Evidence
Evidence level: strong.
Reported safety data
The FDA’s adverse event reporting system (FAERS) has received 43,903 reports mentioning 5-HTP. This reflects reported cases involving the medication in general — not confirmed causation, and not specific to the 5-HTP + supplement combination on this page.
FAERS reports are voluntary and cannot prove that a drug caused an event. Do not use report counts to assess the safety of this specific drug-supplement pair.
Frequently asked questions
Related interactions
All MAOIs (e.g., Phenelzine, Tranylcypromine) interactions → · All 5-HTP interactions →
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Educational only — not medical advice.
Always confirm with your doctor or pharmacist.