Drug & supplement interaction

Phenethylamine (pea) + Guaifenesin

Guaifenesin brand names: Robitussin, Humibid LA, Amibid LA, Numobid, Muco-Fen 800, and others.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Phenethylamine (pea) and Guaifenesin in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first.

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Interaction report

Phenethylamine (pea) and Guaifenesin

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Guaifenesin and Phenethylamine (pea) in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Phenethylamine (pea) safety at a glance

Phenethylamine (pe... overall Use caution May affect heart rate and blood pressure, and human safety data for supplements is limited.
Pregnancy Avoid Not enough safety information; best avoided during pregnancy.
Breastfeeding Avoid Not enough safety information; best avoided while breastfeeding.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Guaifenesin and Phenethylamine (pea)? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Guaifenesin

Interactions in our licensed database are recorded against drug classes, not just single drug names. Guaifenesin is filed under 2 classifications — including oral drugs. Phenethylamine (pea) has documented interactions with 2 drug classes — the most serious being monoamine oxidase inhibitors (maois) (moderate) and serotonergic drugs (moderate) — and none of Guaifenesin’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Phenethylamine (pea) Does Interact With Other Medications

Phenethylamine (pea) has 187 moderate known drug interactions in our database — Guaifenesin isn’t one of them. If you take anything else, check it against the full list below.

Moderate 187 No known interaction 2,643 (incl. Guaifenesin)
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.

What to actually watch for

What Phenethylamine (pea) Itself Has Been Linked To

This is not an interaction — nothing below involves Guaifenesin. It is the side-effect record for Phenethylamine (pea) on its own, from the licensed Natural Medicines monograph. If something new turns up after you add Phenethylamine (pea), this list is the first place to look.

  • Weight loss Additional detail

    “A case of anxiety and agitation has been reported for an individual who consumed a weight loss product containing phenethylamine 200-300 mg, caffeine 500-750 mg, bitter orange 400-600 mg, willow bark 150-225 mg, cayenne pepper 80-120 mg, 1,3-dimethyloamyloamine 70-105 mg, gooseberry extract 40-60 mg, bergamot orange 40-60 mg, and black pepper 10-15 mg, daily for 2 months.”

    Phenethylamine (pea) · Natural Medicines adverse-effect record, reported in anxiety.

    1 source cited
    1. 24343. Lukasik-Glebocka M, Sommerfeld K, Tezyk A, et al. [Acute poisoning with weight-loss dietary supplement falsely suggesting the use of amphetamine]. Przegl Lek. 2013;70(10):880-3.

    “A case of tachycardia has been reported for an individual who consumed a weight loss product containing phenethylamine 200-300 mg, as well as caffeine 500-750 mg, bitter orange 400-600 mg, willow bark 150-225 mg, cayenne pepper 80-120 mg, 1,3-dimethyloamyloamine 70-105 mg, gooseberry extract 40-60 mg, bergamot orange 40-60 mg, and black pepper 10-15 mg, daily for 2 months.”

    Phenethylamine (pea) · Natural Medicines adverse-effect record, reported in myasthenia gravis.

    1 source cited
    1. 24343. Lukasik-Glebocka M, Sommerfeld K, Tezyk A, et al. [Acute poisoning with weight-loss dietary supplement falsely suggesting the use of amphetamine]. Przegl Lek. 2013;70(10):880-3.
  • A fast or pounding heartbeat Additional detail

    Recorded for Phenethylamine (pea) in the same Natural Medicines adverse-effect record shown under Weight loss above.

  • Anxiety or restlessness Additional detail

    Recorded for Phenethylamine (pea) in the same Natural Medicines adverse-effect record shown under Weight loss above.

Everything above comes from the Natural Medicines adverse-effect record for Phenethylamine (pea) — expand a row for the licensed statement it rests on. We haven’t matched Guaifenesin to its FDA label in our system yet, so we can’t compare its own side-effect list here — the leaflet that comes with your prescription is the authoritative list for Guaifenesin.

From our Q&A

Questions About Phenethylamine (pea) or Guaifenesin

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Phenethylamine (pea) or Guaifenesin, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Guaifenesin

This page covers Phenethylamine (pea) only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Guaifenesin page lists 26 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), Berberine (moderate), Bitter Orange (moderate) and Coffee Charcoal (moderate).

By severity: 2 major · 15 moderate · 9 minor.

From our pharmacist’s overview on the Guaifenesin page

“Guaifenesin (Robitussin, Humibid LA) loosens chest mucus, and by itself it is a mild medicine, but two of the 26 supplements on this list rate major, so those two deserve your attention first. Activated charcoal can bind the drug in your gut and blunt what it does, and grapefruit raises blood levels of dextromethorphan, the cough suppr…”

Reviewed by 2 · Jul 18, 2026

Open the Guaifenesin 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). Even though Phenethylamine (pea) itself has no known interaction with Guaifenesin, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Phenethylamine (pea) and Guaifenesin 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

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

29 days ago today
Medication Guaifenesin
Top half

#941 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.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Phenethylamine (pea) reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Phenethylamine (pea) and Guaifenesin records this page draws on were last updated July 10, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
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.

Not a plant part; a naturally occurring monoamine compound (made in the body and found in some foods) · Capsules, tablets, powders (often combined with other ingredients in pre-workout or 'mood' and 'focus' supplements)

An interaction check asks whether these two react with each other — it does not ask whether Phenethylamine (pea) is a good idea for someone in your situation. Here is what our Phenethylamine (pea) record says about it on its own.

Phenethylamine (pea): dosing

There is no well-established or standardized dose for PEA supplements, and reliable studies on safe and effective amounts are lacking. Products vary widely in how much they contain and what else they are combined with.If you choose to try it, follow the directions on the product label and do not exceed the recommended amount.

From our Phenethylamine (pea) monograph — the full record covers uses, side effects and every documented interaction.

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

About Guaifenesin

What Is Guaifenesin Used For?

Brand names: Robitussin, Humibid LA, Amibid LA, Numobid, Muco-Fen 800, Bidex, Organidin, X-pect, Mucinex

Guaifenesin helps loosen phlegm (mucus) and thin bronchial secretions — the sticky fluid in your airways — so your cough can clear it out more effectively. It is used to relieve chest congestion associated with colds, respiratory infections, and other conditions that cause a mucus-filled cough.

This use is supported across multiple products including tablets, extended-release tablets, and oral solutions such as Childrens Mucus Relief, Tussin, Guaifenesin STRAWBERRY-BANANA FLAVOR, 12 Hour Mucus Relief, 365 Whole Foods Market Guaifenesin, Dr. Simi Mucus Relief, and others.

See full Guaifenesin 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
187Moderate
0Minor
2,642No known interaction
187 Moderate 2,642 No interaction
Moderate

187 interactions

Showing 60 of 187 moderate interactions — see all 187 on the Phenethylamine (pea) page.

No interaction 2,642 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 2,642 medications checked with no known interaction — see the full Phenethylamine (pea) list.

See the full Phenethylamine (pea) interactions page
See every supplement checked against Guaifenesin, ranked by severity
Evidence & sources

Phenethylamine (pea) References

The 9 references that drive our Phenethylamine (pea) monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  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. Lukasik-Glebocka M, Sommerfeld K, Tezyk A, et al. [Acute poisoning with weight-loss dietary supplement falsely suggesting the use of amphetamine]. Przegl Lek. 2013;70(10):880-3.
  5. 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.
  6. 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
  7. 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.
  8. 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.
  9. Lindemann L, Hoener MC. A renaissance in trace amines inspired by a novel GPCR family. Trends Pharmacol Sci. 2005;26(5):274-81. PubMed

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Phenethylamine (pea) and Guaifenesin Together: Common Questions

Is it safe to take Phenethylamine (pea) with Guaifenesin?
We do not list a known interaction between Phenethylamine (pea) and Guaifenesin. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
How was the Phenethylamine (pea) and Guaifenesin combination checked?
Interactions in our licensed database are recorded against drug classes. Guaifenesin is filed under 2 classifications, and Phenethylamine (pea) has documented interactions with 2 drug classes — none of Guaifenesin's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Phenethylamine (pea) interact with any other medications?
Yes. Phenethylamine (pea) has 187 documented drug interactions in our database — Guaifenesin is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Guaifenesin interact with any supplements?
Yes. Guaifenesin has documented interactions with 26 supplements in our database — Phenethylamine (pea) is not one of them. The Guaifenesin interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

Phenethylamine (pea) monograph Uses, safety profile, and every drug interaction in one place Guaifenesin drug information The full plain-English guide to this medication Guaifenesin supplement interactions Every supplement checked against Guaifenesin, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 9 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Guaifenesin 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.