Drug & supplement interaction

Phenethylamine (pea) + Phenelzine Sulfate

Phenelzine Sulfate brand name: Nardil.

Moderate Interaction
Medically reviewed by · Updated September 2026
The bottom line Moderate

Phenelzine Sulfate falls into 2 drug categories that Phenethylamine (pea) can interact with; the most serious is rated moderate. Theoretically, combining serotonergic drugs with phenethylamine might increase the risk of serotonergic adverse effects.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions2
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Phenethylamine (pea) and Phenelzine Sulfate

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Phenethylamine (pea) interacts with whole categories of medication. Phenelzine Sulfate falls into 2 of those categories, so it can interact with Phenethylamine (pea) in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

SEROTONERGIC DRUGS

1 of 2

Why this applies to Phenelzine Sulfate

Phenelzine Sulfate falls under SEROTONERGIC DRUGS — the group Phenethylamine (pea) interacts with.

Theoretically, combining serotonergic drugs with phenethylamine might increase the risk of serotonergic adverse effects.
Animal research shows that phenethylamine increases levels of serotonin, norepinephrine, and dopamine. Theoretically, combining serotonergic drugs with phenethylamine might increase the risk of additive serotonergic adverse effects, including serotonin syndrome and cerebral vasoconstrictive disorders. However, low-quality clinical research has used phenethylamine with selegiline, a monoamine oxidase inhibitor (MAOI), with apparent safety.
Severity Moderate Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the key thing with Nardil (phenelzine): it's an MAO inhibitor, meaning it blocks the very enzyme (monoamine oxidase) that normally breaks down PEA in your body. PEA is cleared mostly by MAO-B, so if that enzyme is shut down, PEA can pile up and push your dopamine and norepinephrine levels higher than expected.

On paper, that combo could raise the risk of a dangerous spike in blood pressure, along with serotonin-related problems like agitation, racing heart, sweating, tremor, or confusion. Honestly, the human evidence here is thin and mostly theoretical, but because phenelzine is one of the riskier drugs for these kinds of reactions, I'd treat this pairing with real caution. Please don't add PEA without first checking with your doctor or pharmacist.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Singhal AB, Caviness VS, Begleiter AF, et al. Cerebral vasoconstriction and stroke after use of serotonergic drugs. Neurology 2002;58:130-3. PubMed
  2. Sabelli H, Fink P, Fawcett J, et al. Sustained antidepressant effect of PEA replacement. J Neuropsychiatry Clin Neurosci. 1996;8(2):168-71.
  3. Xie Z, Miller G. Beta-phenylehtylamine alters monoamine transporter function via trace amine-associated receptor 1: implication for modulatory roles of trace amines in brain. J Pharmacol Exp Ther. 2008;325(2):617-28.
  4. Nakamura M, Ishii A, Nakahara D. Characterization of beta-phenyltheylamine-induced monoamine release in rat nucleus accumbens: a microdialysis study. Eur J Pharmacol. 1998;349(2-3):163-9.
  5. Bailey B, Philips S, Boulton A. In vivo release of endogenous dopamine, 5-hydroxytryptamine and some of their metabolites from rat caudate nucleus by phenylethylamine. Neurochem Res. 1987;12(2):173-8. PubMed
Moderate

MONOAMINE OXIDASE INHIBITORS (MAOIs)

2 of 2

Phenelzine Sulfate also falls under MONOAMINE OXIDASE INHIBITORS (MAOIs).

Theoretically, taking phenethylamine concomitantly with MAOIs may increase adverse effects.
In humans, phenethylamine is oxidized by MAO-B to form the inactive metabolite phenylacetic acid. Animal research shows that administering an MAOI prior to phenethylamine increases the amphetamine-like effects of phenethylamine. However, low-quality clinical research has used phenethylamine with selegiline, an MAOI, with apparent safety.
Severity Moderate Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the key thing about Nardil (phenelzine): it's an MAO inhibitor, meaning it shuts down the very enzyme (monoamine oxidase) that normally breaks PEA down in your body. So if you take a PEA supplement while on Nardil, the PEA isn't cleared like it should be. It can pile up and push the release of norepinephrine and dopamine, which is exactly what we worry about.

In real terms, that buildup could spike your blood pressure and heart rate, sometimes sharply. With MAOIs we always watch for that kind of pressure surge, so this combo is one I'd steer clear of. The hard human evidence here is thin (mostly lab and animal work), but the mechanism is solid enough that I wouldn't gamble on it. Please check with your pharmacist or doctor before mixing the two.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Sabelli H, Fink P, Fawcett J, et al. Sustained antidepressant effect of PEA replacement. J Neuropsychiatry Clin Neurosci. 1996;8(2):168-71.
  2. Mantegazza P, Riva M. Amphetamine-like activity of beta-phenethylamine after a monoamine oxidase inhibitor in vivo. Journal of Pharmacy and Pharmacology. 1963;151(1):472-8.
  3. Grimsby J, Toth M, Chen K, et al. Increased stress response and beta-phenylethylamine in MAOB-deficient mice. Nat Genet. 1997;17(2):206-10.
  4. Lindemann L, Hoener MC. A renaissance in trace amines inspired by a novel GPCR family. Trends Pharmacol Sci. 2005;26(5):274-81. PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Phenethylamine (pea) Also Interacts With Other Medications

Phenethylamine (pea) has 186 moderate known drug interactions in our database — the Phenelzine Sulfate one above is among them. If you take anything else, check it against the full list below.

Moderate 186 No known interaction 2,644 (incl. Phenelzine Sulfate)
Taking anything else?

Check Another of Your Medications Against Phenethylamine (pea)

Covers the 2,830 medications we’ve checked against Phenethylamine (pea). Pick one to open its full report.

Everything else you take

See Every Supplement That Interacts With Phenelzine Sulfate

This page covers Phenethylamine (pea) only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Phenelzine Sulfate page lists 144 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: 1,4-butanediol (major), Activated Charcoal (major), Beer (major), Bitter Orange (major) and Brewer's Yeast (major).

By severity: 18 major · 111 moderate · 15 minor.

From our pharmacist’s overview on the Phenelzine Sulfate page

“Few medications demand as much dietary and supplement care as phenelzine sulfate (Nardil), an older MAOI antidepressant, and this list backs that up, with 18 of its 144 recorded interactions rated major. The two dominant themes are sedation and blood pressure.”

Reviewed by 2 · Jul 18, 2026

Open the Phenelzine Sulfate interaction page

One more smart check

Taking Phenethylamine (pea) as Part of a Dietary Supplement Product? Check It for Interactions

We hold 208 real supplement products containing Phenethylamine (pea), each one broken down to its full ingredient list — and combination products often carry several ingredients besides Phenethylamine (pea). Your product may carry other ingredients that interact with Phenelzine Sulfate too, on top of Phenethylamine (pea) — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Phenethylamine (pea) and Phenelzine Sulfate Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Phenethylamine (pea)
Top half

#493 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Phenelzine Sulfate
Top half

#1,380 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Supplement

About Phenethylamine (pea)

What is Phenethylamine (pea)?

Phenethylamine (pea)
  • Mood support
  • Focus and concentration
  • Energy and pre-workout boost
  • Feeling of well-being
  • Athletic performance

Phenethylamine (PEA) is a natural compound made in the body and found in foods like chocolate; supplements are marketed for mood, focus, and energy. Reliable human research on the supplement is very limited, and it may raise blood pressure or heart rate, so people with heart or blood pressure problems should be cautious and check with a pharmacist or doctor first.

Read the full Phenethylamine (pea) monograph & all interactions
Medication

About Phenelzine

What Is Phenelzine Used For?

Brand name: Nardil

Phenelzine is used to treat depression — specifically the types described as atypical, nonendogenous, or neurotic depression. This often includes people who have a mix of anxiety and depression, or who have phobic or hypochondriacal features (strong fears about illness or physical symptoms).

It is generally not the first antidepressant a doctor will try. It is best suited for patients who have already tried other antidepressants without enough relief. There is less evidence supporting its use in severe depression with classic biological features (called endogenous depression).

See full Phenelzine drug information
Keep checking

Other Drugs & Phenethylamine (pea)

Browse every other medication we’ve checked against Phenethylamine (pea) — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
186Moderate
0Minor
2,643No known interaction
186 Moderate 2,643 No interaction
Moderate

186 interactions

Showing 60 of 186 moderate interactions — see all 186 on the Phenethylamine (pea) page.

No interaction 2,643 drugs checked — show the list

We also checked Phenethylamine (pea) against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,643 medications checked with no known interaction — see the full Phenethylamine (pea) list.

See the full Phenethylamine (pea) interactions page
See every supplement checked against Phenelzine Sulfate, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Phenethylamine (pea) monograph › Uses, safety, and every drug interaction in one place Phenelzine Sulfate supplement interactions › Every supplement checked against Phenelzine Sulfate, ranked by severity Phenelzine drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Phenethylamine (pea) and Phenelzine Sulfate Together: Common Questions

Can you take Phenethylamine (pea) with Phenelzine Sulfate?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
Why are there 2 interactions listed for Phenethylamine (pea) and Phenelzine Sulfate?
Phenelzine Sulfate belongs to more than one drug category, and Phenethylamine (pea) interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Phenethylamine (pea) and Phenelzine Sulfate interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Phenelzine Sulfate and Phenethylamine (pea)?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.