Drug & supplement interaction

Fermented Wheat Germ Extract + Dextromethorphan

Dextromethorphan brand names: Hold, Benylin Adult, Benylin Pediatric, Theraflu Thin Strips Long Acting Cough, Neo Citran Thin Strips Cough.

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

Fermented Wheat Germ Extract has a moderate interaction with Dextromethorphan. Theoretically, concomitant use of fermented wheat germ extract with serotonergic medications may increase the risk of serotonergic adverse effects.

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

Fermented Wheat Germ Extract and Dextromethorphan

Here is the interaction we found between these two, with the evidence behind it.

Moderate

SEROTONERGIC DRUGS

Why this applies to Dextromethorphan

Dextromethorphan falls under SEROTONERGIC DRUGS — the group Fermented Wheat Germ Extract interacts with.

Theoretically, concomitant use of fermented wheat germ extract with serotonergic medications may increase the risk of serotonergic adverse effects.
Animal research shows that fermented wheat germ can increase levels of serotonin in the brain.
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 gist of this one. Dextromethorphan, the cough suppressant you'll find in lots of cold remedies, gently nudges up serotonin activity in the brain. Fermented wheat germ extract has been shown, in animal studies only, to raise brain serotonin too. So the theory is that combining them could stack serotonin a bit higher than either alone.

If serotonin climbed too far, you might feel things like restlessness, shakiness, a fast heartbeat, sweating, or feeling flushed. I'll be honest though, this is a very low-quality, theoretical concern based on lab and animal work, not real cases in people. For most folks taking normal cough doses, it's unlikely to cause trouble. Still, if you're using both, mention it to your pharmacist or oncologist so they can keep an eye on you.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Hu Z, Zhao P, Liao A, et al. Fermented Wheat Germ Alleviates Depression-like Behavior in Rats with Chronic and Unpredictable Mild Stress. Foods 2023;12(5):920. 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

Fermented Wheat Germ Extract Also Interacts With Other Medications

Fermented Wheat Germ Extract has 302 moderate known drug interactions in our database — the Dextromethorphan one above is one of them. If you take anything else, check it against the full list below.

Moderate 302 No known interaction 2,528 (incl. Dextromethorphan)
Taking anything else?

Check Another of Your Medications Against Fermented Wheat Germ Extract

Covers the 2,830 medications we’ve checked against Fermented Wheat Germ Extract. Pick one to open its full report.

From our Q&A

Questions About Fermented Wheat Germ Extract or Dextromethorphan

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Fermented Wheat Germ Extract or Dextromethorphan, 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 Dextromethorphan

This page covers Fermented Wheat Germ Extract only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Dextromethorphan page lists 171 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), Lithium (major), St. John's Wort (major) and 1,3-dmaa (moderate).

By severity: 4 major · 125 moderate · 42 minor.

From our pharmacist’s overview on the Dextromethorphan page

“A glass of grapefruit juice can push dextromethorphan (Benylin, Hold, and other cough medicines) to higher levels than intended, one of four major-rated entries among the 171 supplements and herbs on file, and the list as a whole warrants real care. Most interactions trace back to the liver enzymes (CYP3A4 and CYP2D6) that clear dextro…”

Reviewed by 2 · Jul 18, 2026

Open the Dextromethorphan interaction page

How much people look this up

Where Fermented Wheat Germ Extract and Dextromethorphan 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 Fermented Wheat Germ Extract
Steady interest

#1,413 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Dextromethorphan
Top 5%

#80 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 Fermented Wheat Germ Extract

What is Fermented Wheat Germ Extract?

  • Cancer supportive care (as a complementary product)
  • Immune support
  • General wellness during cancer treatment
  • Antioxidant support
  • Fatigue during illness

Fermented wheat germ extract is a supplement made by fermenting wheat germ with yeast, and it is most often marketed for people going through cancer treatment. While some early research and a few small studies are interesting, the overall evidence is limited and far from conclusive, so it should never replace standard medical care. Talk with your oncologist or pharmacist before using it, since it is a supplement and not an approved treatment.

Read the full Fermented Wheat Germ Extract monograph & all interactions
Medication

About Dextromethorphan

What Is Dextromethorphan Used For?

Brand names: Hold, Benylin Adult, Benylin Pediatric, Theraflu Thin Strips Long Acting Cough, Neo Citran Thin Strips Cough

Dextromethorphan temporarily relieves cough due to minor throat and bronchial irritation, such as the kind that comes with the common cold or breathing in irritants. It also helps reduce the urge to cough so you — or your child — can get to sleep.

Some products, including CVS Long Acting Cough and Premier Value Tussin Cough oral liquids, are also indicated to help loosen phlegm (mucus) and thin bronchial secretions to help drain the airways.

See full Dextromethorphan drug information
Keep checking

Other Drugs & Fermented Wheat Germ Extract

Browse every other medication we’ve checked against Fermented Wheat Germ Extract — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
302Moderate
0Minor
2,527No known interaction
302 Moderate 2,527 No interaction
Moderate

302 interactions

Showing 60 of 302 moderate interactions — see all 302 on the Fermented Wheat Germ Extract page.

No interaction 2,527 drugs checked — show the list

We also checked Fermented Wheat Germ Extract against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,527 medications checked with no known interaction — see the full Fermented Wheat Germ Extract list.

See the full Fermented Wheat Germ Extract interactions page
See every supplement checked against Dextromethorphan, 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
Fermented Wheat Germ Extract monograph › Uses, safety, and every drug interaction in one place Dextromethorphan supplement interactions › Every supplement checked against Dextromethorphan, ranked by severity Dextromethorphan 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 Fermented Wheat Germ Extract and Dextromethorphan Together: Common Questions

Can you take Fermented Wheat Germ Extract with Dextromethorphan?
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.
How serious is the Fermented Wheat Germ Extract and Dextromethorphan 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 Dextromethorphan and Fermented Wheat Germ Extract?

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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.