Drug & supplement interaction

Horny Goat Weed + Salmeterol

Salmeterol brand name: Serevent.

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

Horny Goat Weed has a moderate interaction with Salmeterol. Theoretically, horny goat weed might increase the effects and side effects of CYP3A4 substrates.

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

Horny Goat Weed and Salmeterol

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

Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

Why this applies to Salmeterol

Salmeterol falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES — the group Horny Goat Weed interacts with.

Theoretically, horny goat weed might increase the effects and side effects of CYP3A4 substrates.
In vitro, horny goat weed extract inhibits CYP3A4 and suppresses CYP3A4 mRNA expression. This effect has not been reported in humans.
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 for your Serevent (salmeterol) inhaler. Your liver uses an enzyme called CYP3A4 to clear salmeterol out of your system. In lab dish studies, horny goat weed seems to slow that enzyme down. If that held true in people, salmeterol could build up a bit higher than usual, which might mean more of its typical side effects, like a fast or pounding heartbeat, jitteriness, shaky hands, headache, or muscle cramps.

The honest part: this is only theoretical, based on test-tube work, and it has not been seen in actual patients. So I wouldn't lose sleep over it, but since salmeterol already nudges your heart rate, it's worth a quick chat with your pharmacist or doctor before adding this herb.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Li K, Yu XH, Maskey AR, et al. Cytochrome P450 3A4 suppression by epimedium and active compound kaempferol leads to synergistic anti-inflammatory effect with corticosteroid. Front Pharmacol 2023;13:1042756. 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

Horny Goat Weed Also Interacts With Other Medications

Horny Goat Weed has 962 moderate known drug interactions in our database — the Salmeterol one above is one of them. If you take anything else, check it against the full list below.

Moderate 962 No known interaction 1,868 (incl. Salmeterol)
Taking anything else?

Check Another of Your Medications Against Horny Goat Weed

Covers the 2,830 medications we’ve checked against Horny Goat Weed. Pick one to open its full report.

From our Q&A

Questions About Horny Goat Weed or Salmeterol

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Horny Goat Weed or Salmeterol, 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 Salmeterol

This page covers Horny Goat Weed only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Salmeterol page lists 141 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: American Hellebore (major), Arsenic (major), Cesium (major), Ephedra (major) and Grapefruit (major).

By severity: 7 major · 105 moderate · 29 minor.

From our pharmacist’s overview on the Salmeterol page

“Salmeterol (Serevent) is the long-acting inhaler taken twice daily for asthma or COPD, and its supplement list is one I would approach with real caution. Seven of the 141 ingredients on file rate major: grapefruit can raise salmeterol levels by blocking the enzyme that clears it, St.”

Reviewed by 2 · Jul 18, 2026

Open the Salmeterol interaction page

One more smart check

Taking Horny Goat Weed as Part of a Dietary Supplement Product? Check It for Interactions

We hold 183 real supplement products containing Horny Goat Weed, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Horny Goat Weed. Your product may carry other ingredients that interact with Salmeterol too, on top of Horny Goat Weed — 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 Horny Goat Weed and Salmeterol 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 Horny Goat Weed
Top 25%

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

29 days ago today
Medication Salmeterol
Top half

#956 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 Horny Goat Weed

What is Horny Goat Weed?

Horny Goat Weed
  • Erectile dysfunction
  • Low libido
  • Fatigue and low energy
  • Bone health
  • Joint and menopausal symptoms
  • General 'vitality' or performance

Horny goat weed (Epimedium) is a traditional Chinese herb most often marketed for low libido and erectile problems, but solid human evidence for these uses is lacking. While short-term use seems generally tolerated by some people, quality and safety are not well studied, so talk to your pharmacist or doctor before trying it—especially if you have heart problems or take other medicines.

Read the full Horny Goat Weed monograph & all interactions
Medication

About Salmeterol Oral Inhalation

What Is Salmeterol Oral Inhalation Used For?

Brand name: Serevent

Serevent Diskus (salmeterol inhalation powder) is used for three main purposes: treating asthma in patients aged 4 and older alongside an inhaled corticosteroid (ICS), preventing exercise-induced bronchospasm (EIB) in patients aged 4 and older, and providing long-term maintenance treatment of bronchospasm associated with COPD — including chronic bronchitis and emphysema — in adults.

Important: Serevent Diskus is not a rescue inhaler. It will not relieve a sudden asthma or COPD attack. For asthma, it must always be used together with an inhaled corticosteroid — using it alone for asthma is contraindicated due to a serious risk of asthma-related death.

See full Salmeterol Oral Inhalation drug information
Keep checking

Other Drugs & Horny Goat Weed

Browse every other medication we’ve checked against Horny Goat Weed — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
962Moderate
0Minor
1,867No known interaction
962 Moderate 1,867 No interaction
Moderate

962 interactions

Showing 60 of 962 moderate interactions — see all 962 on the Horny Goat Weed page.

No interaction 1,867 drugs checked — show the list

We also checked Horny Goat Weed against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 1,867 medications checked with no known interaction — see the full Horny Goat Weed list.

See the full Horny Goat Weed interactions page
See every supplement checked against Salmeterol, 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
Horny Goat Weed monograph › Uses, safety, and every drug interaction in one place Salmeterol supplement interactions › Every supplement checked against Salmeterol, ranked by severity Salmeterol Oral Inhalation 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 Horny Goat Weed and Salmeterol Together: Common Questions

Can you take Horny Goat Weed with Salmeterol?
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 Horny Goat Weed and Salmeterol 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 Salmeterol and Horny Goat Weed?

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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.