Drug & supplement interaction

Horny Goat Weed + Doxycycline

Doxycycline brand names: Vibra-Tabs, Vibramycin, Doryx, Monodox, Doxycin, and others.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 13, 2026
The bottom line No known interaction

We found no known interaction between Horny Goat Weed and Doxycycline 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. Additionally, although there is no interaction, the label for Doxycycline states a food rule worth keeping to, and the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Horny Goat Weed and Doxycycline

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 Doxycycline and Horny Goat Weed 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.

Horny Goat Weed safety at a glance

Horny Goat Weed overall Use caution Human safety data is limited; short-term use may be tolerated but quality varies between products.
Pregnancy Possibly Unsafe When used orally. Horny goat weed might have androgenic activity. Theoretically, it might harm a developing fetus; avoid using. Read the full pregnancy detail
Breastfeeding Avoid Not enough safety data; avoid while breastfeeding.

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Doxycycline and Horny Goat Weed? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Doxycycline

Interactions in our licensed database are recorded against drug classes, not just single drug names. Doxycycline is filed under 9 classifications — including tetracycline antibiotics, antibiotic drugs, p-glycoprotein substrates. Horny Goat Weed has documented interactions with 6 drug classes — the most serious being anticoagulant/antiplatelet drugs (moderate), antihypertensive drugs (moderate) and cytochrome p450 1a2 (cyp1a2) substrates (moderate) — and none of Doxycycline’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

Horny Goat Weed Does Interact With Other Medications

Horny Goat Weed has 963 moderate known drug interactions in our database — Doxycycline isn’t one of them. If you take anything else, check it against the full list below.

Moderate 963 No known interaction 1,867 (incl. Doxycycline)
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.

What to actually watch for

No Interaction Found — But Data Suggests Horny Goat Weed and Doxycycline May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do. 2 of them are worth acting on rather than waiting out — marked below.

  • Liver problems Worth acting on Additional detail

    Horny Goat Weed

    “A case of hepatotoxicity characterized by abdominal pain, nausea, vomiting, and fever has been reported in a 40-year-old male patient with hepatitis C, after a month of taking one tablet daily of a combination product containing horny goat weed and multiple other ingredients (Enzyte, Vianda).”

    Horny Goat Weed · Natural Medicines adverse-effect record, reported in hepatitis.

    2 sources cited
    1. 91590. Ramanathan VS, Mitropoulos E, Shlopov B, et al. An Enzyte'ing' case of acute hepatitis. J Clin Gastroenterol 2011;45(9):834-5. PubMed
    2. 112707. Tan K, Yang W, Pang L, Hou F. Differences in clinical characteristics among 726 patients with Chinese herbal medicine- or Western medicine-induced liver injury. Medicine (Baltimore) 2022;101(32):e29909. PubMed

    Doxycycline

    Listed in the ADVERSE REACTIONS section of the FDA label for Doxycycline. Read the label on DailyMed ›

  • Bleeding or bruising Worth acting on Additional detail

    Horny Goat Weed

    “Orally, long-term use of horny goat weed has been associated with reports of vomiting, dry mouth, thirst, and nosebleed.”

    Horny Goat Weed · Natural Medicines adverse-effect record, reported in dry mouth.

    1 source cited
    1. 10346. Cirigliano MD, Szapary PO. Horny goat weed for erectile dysfunction. Alt Med Alert 2001;4:19-22.

    Doxycycline

    Listed in the ADVERSE REACTIONS section of the FDA label for Doxycycline. Read the label on DailyMed ›

  • Dry mouth / Vomiting Additional detail

    Horny Goat Weed

    Recorded for Horny Goat Weed in the same Natural Medicines adverse-effect record shown under Bleeding or bruising above.

    Doxycycline

    Listed in the ADVERSE REACTIONS section of the FDA label for Doxycycline. Read the label on DailyMed ›

  • Stomach pain / Nausea Additional detail

    Horny Goat Weed

    Recorded for Horny Goat Weed in the same Natural Medicines adverse-effect record shown under Liver problems above.

    Doxycycline

    Listed in the ADVERSE REACTIONS section of the FDA label for Doxycycline. Read the label on DailyMed ›

Reported for Horny Goat Weed but not commonly for Doxycycline: dizziness, increased thirst and fever.

Effects for Doxycycline come from the ADVERSE REACTIONS section of its FDA label; effects for Horny Goat Weed come from the Natural Medicines adverse-effect record, quoted above. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Horny Goat Weed in Pregnancy & Breastfeeding

Pregnancy Possibly Unsafe

When used orally. Horny goat weed might have androgenic activity. Theoretically, it might harm a developing fetus; avoid using.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

How to take them

Some Doxycycline Products Have a Food Rule — Horny Goat Weed Should Not Break It

At least one FDA label for a product containing Doxycycline says to take it on an empty stomach. Most supplements — Horny Goat Weed included — are taken with a meal, so the easy mistake is swallowing both together at breakfast. Where that rule applies, keep Doxycycline on its own and move Horny Goat Weed to a meal later in the day.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Doxycycline products can carry different directions, and extended-release forms often differ from immediate-release ones. The label we read is quoted below — check the directions on your own box or bottle, or ask your pharmacist, for how to take the exact product you were given.

2 DOSAGE AND ADMINISTRATION Take one Doxycycline capsule (40 mg) once daily in the morning on an empty stomach, preferably at least one hour prior to or two hours after meals.

From the Dosage and Administration section of the FDA label we read for Doxycycline — where that label names a specific product, the instruction is that product's. Read the label on DailyMed ›

A food rule is not an interaction — it is about how much of the medicine you absorb. The directions that came with your own product, and your pharmacist, outrank anything on this page.

From our Q&A

Questions About Horny Goat Weed or Doxycycline

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 Doxycycline, 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 Doxycycline

This page covers Horny Goat Weed only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Doxycycline page lists 166 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Asarabacca (major), Beer (major), Oleander (major) and Siberian Cocklebur (major).

By severity: 7 major · 139 moderate · 20 minor.

From our pharmacist’s overview on the Doxycycline page

“St. John's wort is the supplement I would flag first for anyone on doxycycline (Vibramycin, Doryx), because it can speed the antibiotic out of the body and leave an infection undertreated.”

Reviewed by 2 · Jul 18, 2026

Open the Doxycycline 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. Even though Horny Goat Weed itself has no known interaction with Doxycycline, 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 Horny Goat Weed and Doxycycline 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%

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

29 days ago today
Medication Doxycycline
Top 5%

#44 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 Horny Goat Weed reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Horny Goat Weed and Doxycycline records this page draws on were last updated July 11, 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 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.

Epimedium grandiflorum · Berberidaceae · Leaves and aerial parts (sometimes whole herb) · Capsules, tablets, powders, tinctures, teas, and combination products

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

Horny Goat Weed: dosing

There is no well-established standard dose for horny goat weed. Products differ a lot in how they are made and how much active compound they contain, so amounts on labels are not comparable across brands.If you choose to try it, follow the directions on the product label and do not exceed the recommended amount.

From our Horny Goat Weed monograph — the full record covers uses, side effects and every documented interaction.

Read the full Horny Goat Weed monograph & all interactions
Medication

About Doxycycline

What Is Doxycycline Used For?

Brand names: Vibra-Tabs, Vibramycin, Doryx, Monodox, Doxycin, Doxy, Doxylin, Doxy-D, Periostat, Doxycycline Injection, Oracea, Xyrosa

Doxycycline belongs to the tetracycline family of antibiotics. It's prescribed for many types of bacterial infections, including respiratory tract infections, sexually transmitted infections (STIs), tick-borne illnesses like Rocky Mountain spotted fever, and eye infections. It's also used to help prevent malaria and, in some cases, as a helper treatment for severe acne.

In situations where penicillin-type antibiotics can't be used — due to allergy, for example — doxycycline can step in as an alternative. It should only be used for infections that are proven or strongly suspected to be caused by bacteria.

See full Doxycycline 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
963Moderate
0Minor
1,866No known interaction
963 Moderate 1,866 No interaction
Moderate

963 interactions

Showing 60 of 963 moderate interactions — see all 963 on the Horny Goat Weed page.

No interaction 1,866 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 1,866 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 Doxycycline, ranked by severity
Evidence & sources

Horny Goat Weed References

The 11 references that drive our Horny Goat Weed 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. Cirigliano MD, Szapary PO. Horny goat weed for erectile dysfunction. Alt Med Alert 2001;4:19-22.
  2. Partin JF, Pushkin YR. Tachyarrhythmia and hypomania with horny goat weed. Psychosomatics 2004;45:536-7. PubMed
  3. De Naeyer A, Pocock V, Milligan S, De Keukeleire D. Estrogenic activity of a polyphenolic extract of the leaves of Epimedium brevicornum. Fitoterapia 2005;76:35-40. PubMed
  4. Zhang CZ, Wang SX, Zhang Y, et al. In vitro estrogenic activities of Chinese medicinal plants traditionally used for the management of menopausal symptoms. J Ethnopharmacol 2005;98:295-300. PubMed
  5. Yap SP, Shen P, Li J, et al. Molecular and pharmacodynamic properties of estrogenic extracts from the traditional Chinese medicinal herb, Epimedium. J Ethnopharmacol 2007;113:218-24. PubMed
  6. Yan, F. F., Liu, Y., Liu, Y. F., and Zhao, Y. X. Herba Epimedii water extract elevates estrogen level and improves lipid metabolism in postmenopausal women. Phytother.Res. 2008;22(9):1224-1228. PubMed
  7. Ramanathan VS, Mitropoulos E, Shlopov B, et al. An Enzyte'ing' case of acute hepatitis. J Clin Gastroenterol 2011;45(9):834-5. PubMed
  8. Zhong Q, Shi Z, Zhang L, et al. The potential of Epimedium koreanum Nakai for herb-drug interaction. J Pharm Pharmacol 2017;69(10):1398-408. doi: 10.1111/jphp.12773.
  9. Irfan M, Kwon TH, Lee DH, et al. Antiplatelet and Antithrombotic Effects of Epimedium koreanum Nakai. Evid Based Complement Alternat Med. Apr 2021;2021:7071987. PubMed
  10. Tan K, Yang W, Pang L, Hou F. Differences in clinical characteristics among 726 patients with Chinese herbal medicine- or Western medicine-induced liver injury. Medicine (Baltimore) 2022;101(32):e29909. PubMed
  11. 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

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 Horny Goat Weed and Doxycycline Together: Common Questions

Is it safe to take Horny Goat Weed with Doxycycline?
We do not list a known interaction between Horny Goat Weed and Doxycycline. 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.
Do Horny Goat Weed and Doxycycline have any of the same side effects?
Yes — our sources link each of them separately to 6 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
Should I take Horny Goat Weed and Doxycycline at the same time of day?
At least one FDA label for a product containing Doxycycline says to take it on an empty stomach, and supplements are usually taken with a meal — so taking them together at breakfast is the easy mistake. Where that applies, keep Doxycycline on its own and move Horny Goat Weed to a meal later in the day. Food instructions belong to the product rather than the ingredient, so check the directions on your own box. This is about absorption, not an interaction.
How was the Horny Goat Weed and Doxycycline combination checked?
Interactions in our licensed database are recorded against drug classes. Doxycycline is filed under 9 classifications, and Horny Goat Weed has documented interactions with 6 drug classes — none of Doxycycline'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 Horny Goat Weed interact with any other medications?
Yes. Horny Goat Weed has 963 documented drug interactions in our database — Doxycycline 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 Doxycycline interact with any supplements?
Yes. Doxycycline has documented interactions with 166 supplements in our database — Horny Goat Weed is not one of them. The Doxycycline 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

Horny Goat Weed monograph Uses, safety profile, and every drug interaction in one place Doxycycline drug information The full plain-English guide to this medication Doxycycline supplement interactions Every supplement checked against Doxycycline, 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 11 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Doxycycline 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.