Medication interaction hub

What Supplements Interact with Valacyclovir?

Valacyclovir brand name: Valtrex. Every interaction below applies to the brands too.

27 Interactions 1 Major 17 Moderate 9 Minor
Curated & coded by · Clinical Pharmacist · Updated October 5, 2026

Drug–supplement interaction data sourced from Natural Medicines Pro, the licensed clinical database from TRC Healthcare / Therapeutic Research, with additional analysis by the HelloPharmacist Pharmacist Team. Our sources · Editorial policy

What is this page for?

One answer, for one medication: what supplements and herbal products interact with Valacyclovir? Every vitamin, herb, and supplement ingredient we’ve checked against it is on this page, ranked by severity, each linking to the full report for that exact pair.

This page covers supplement interactions only — to check Valacyclovir against your other medications, use the drug–drug interaction checker. Educational information from our licensed clinical databases, not medical advice. Our editorial policy

HelloPharmacist Bottom Line
Our Pharmacist Explains
What is this? The interaction data in the HelloPharmacist supplement database is licensed from Natural Medicines Pro by TRC Healthcare (Therapeutic Research). HelloPharmacist pharmacists often add our own analysis and context on top of that licensed data — such as this Bottom Line summary and the notes on individual interaction pages — and any such commentary is noted as ours.

Valacyclovir (Valtrex) works against herpes outbreaks only if enough of it gets absorbed into your blood, and most of this list threatens exactly that. Of the 27 supplements on file, 17 can change how well oral medicines like this one are absorbed, and the single major-rated entry, activated charcoal, binds drugs in the gut outright. Treat these pairings as a genuine safety question, starting with charcoal.

Beyond absorption, six ingredients, ginkgo and melatonin among them, may lower the seizure threshold, worth respecting because valacyclovir at high levels can irritate the nervous system in some people. Four more slow the kidney transporter that clears this drug, which can push its levels higher. Seventeen entries rate moderate and nine minor, but bulky fibers still belong well away from your antiviral, and charcoal deserves a conversation with your pharmacist before you take any of it.

— , Clinical Pharmacist · July 18, 2026

Major 1 Moderate 17 Minor 9 No known interaction 1,425

This box checks one ingredient at a time (like turmeric or magnesium). Taking a supplement product with a whole label of ingredients? Search the product instead — we check every ingredient on it ↓

Top Ingredient Interactions

Valacyclovir: Top Interactions at a Glance

The most significant Valacyclovir supplement & herbal interactions, colored by severity. Tap any ingredient to open the full report for that pair.

Showing the 12 highest-ranked of 27 interacting ingredients — plus 1,425 more checked with no known interaction. See the complete ranked list.

Start here

The Major Interactions to Know About

The most clinically significant Valacyclovir + supplement combinations in our database, best-documented first. Open any card for the full report.

Major Likelihood Probable Activated Charcoal + Valacycloviri

Activated charcoal reduces systemic exposure to many drugs, including those that undergo enterohepatic recirculation, regardless of the route of administration.

Read the full interaction
The complete list

Every Supplement Checked Against Valacyclovir

All 1,452 ingredients in our database, ranked by severity — 27 with a Valacyclovir interaction on file and 1,425 with none found. Filter by severity or search any ingredient; hover the for what each ingredient is.

Looking for an interaction with a specific supplement product? Search products instead ↓

Straight answers

Can You Take It With Valacyclovir?

One-line answers, one card per combination — scroll through today’s 20 and tap any card for the full report. A different set rotates in daily until every combination has had its turn.

Can you take Thyroid Extract with Valacyclovir?

Minor Usually — this is a minor-rated interaction, generally not clinically significant but worth mentioning to your pharmacist. Food and medications can interfere with thyroid hormone absorption.

Full Thyroid Extract + Valacyclovir answer

Can you take Gum Arabic with Valacyclovir?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, gum arabic can alter the absorption of oral drugs due to its fiber content.

Full Gum Arabic + Valacyclovir answer

Can you take Melatonin with Valacyclovir?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, taking melatonin with drugs that lower the seizure threshold might increase the risk of seizure activity.

Full Melatonin + Valacyclovir answer

Can you take Quercetin with Valacyclovir?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, concomitant use might increase the effects and adverse effects of OAT1 substrates.

Full Quercetin + Valacyclovir answer

Can you take Rauwolscine with Valacyclovir?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, taking rauwolscine with seizure threshold lowering drugs might increase the risk of adverse convulsant effects.

Full Rauwolscine + Valacyclovir answer

Can you take Slippery Elm with Valacyclovir?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, slippery elm may slow the absorption and reduce serum levels of oral drugs.

Full Slippery Elm + Valacyclovir answer

Can you take Thuja with Valacyclovir?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Thuja products can contains significant amounts of thujone, a neurotoxin.

Full Thuja + Valacyclovir answer

Can you take Tragacanth with Valacyclovir?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, tragacanth might alter absorption of oral drugs.

Full Tragacanth + Valacyclovir answer

Can you take Agar with Valacyclovir?

Minor Usually — this is a minor-rated interaction, generally not clinically significant but worth mentioning to your pharmacist. Agar forms a thick gel, which may disrupt the absorption of nutrients and medications.

Full Agar + Valacyclovir answer

Can you take Algin with Valacyclovir?

Minor Usually — this is a minor-rated interaction, generally not clinically significant but worth mentioning to your pharmacist. Theoretically, algin can alter the absorption of oral drugs.

Full Algin + Valacyclovir answer

Can you take Black Psyllium with Valacyclovir?

Minor Usually — this is a minor-rated interaction, generally not clinically significant but worth mentioning to your pharmacist. Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.

Full Black Psyllium + Valacyclovir answer

Can you take Blond Psyllium with Valacyclovir?

Minor Usually — this is a minor-rated interaction, generally not clinically significant but worth mentioning to your pharmacist. Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.

Full Blond Psyllium + Valacyclovir answer

Can you take Carob with Valacyclovir?

Minor Usually — this is a minor-rated interaction, generally not clinically significant but worth mentioning to your pharmacist. Theoretically, carob might also impair the absorption of oral drugs.

Full Carob + Valacyclovir answer

Can you take Karaya Gum with Valacyclovir?

Minor Usually — this is a minor-rated interaction, generally not clinically significant but worth mentioning to your pharmacist. Co-administration of oral drugs with bulk forming laxatives such as karaya gum may decrease, increase, or have no effect on the absorption o...

Full Karaya Gum + Valacyclovir answer

Can you take Marshmallow with Valacyclovir?

Minor Usually — this is a minor-rated interaction, generally not clinically significant but worth mentioning to your pharmacist. Theoretically, mucilage in marshmallow might impair absorption of oral drugs.

Full Marshmallow + Valacyclovir answer

Can you take Xanthan Gum with Valacyclovir?

Minor Usually — this is a minor-rated interaction, generally not clinically significant but worth mentioning to your pharmacist. Theoretically, xanthan gum can alter the absorption of oral drugs due to its fiber qualities.

Full Xanthan Gum + Valacyclovir answer

Can you take Activated Charcoal with Valacyclovir?

Major Use real caution — this is a major-rated interaction, generally best avoided or used only under close supervision. Activated charcoal reduces systemic exposure to many drugs, including those that undergo enterohepatic recirculation, regardless of the rout...

Full Activated Charcoal + Valacyclovir answer

Can you take Coffee Charcoal with Valacyclovir?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Coffee charcoal can reduce the absorption of orally administered drugs and should be separated from oral drug administration by at least two...

Full Coffee Charcoal + Valacyclovir answer

Can you take European Mandrake with Valacyclovir?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, concurrent use might increase absorption of some drugs because of inhibited gastrointestinal (GI) motility caused by European...

Full European Mandrake + Valacyclovir answer

Can you take Glucomannan with Valacyclovir?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, glucomannan may decrease absorption of drugs taken orally.

Full Glucomannan + Valacyclovir answer
Read the list like a pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

  • Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
  • Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
  • Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
  • No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

  • Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
  • Probable. Interaction 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.
  • Possible. 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
  • Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

  • Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
  • Each entry links to a full report with the clinical detail, likelihood, evidence level, and citations for that exact combination.
  • Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

How Does Our Interaction Checker Work?

Behind every verdict on this page is a category system. Our source database doesn’t document supplement interactions drug-by-drug — it documents them against groups of medications that behave the same way (for example, “drugs processed by the CYP3A4 liver enzyme” or “blood-thinning medications”).

So the check works in three steps: (1) Valacyclovir is classified into the pharmacology categories it belongs to, (2) every supplement interaction documented against any of those categories is inherited by Valacyclovir, and (3) each ingredient keeps its own severity, likelihood, and evidence grades from the underlying record. That’s why one supplement can carry several records for one drug — it may interact through more than one category.

Valacyclovir sits in 3 interaction categories. Open any one to see what the group means:

Oral Drugs 17 ingredients

A pharmacology grouping from our source database: medications in this group share a property that certain supplements are known to interact with, so an interaction documented for the group applies to every drug in it.

17 of the supplement ingredients on this page reach Valacyclovir through this category.

Seizure Threshold Lowering Drugs 6 ingredients

A pharmacology grouping from our source database: medications in this group share a property that certain supplements are known to interact with, so an interaction documented for the group applies to every drug in it.

6 of the supplement ingredients on this page reach Valacyclovir through this category.

Organic Anion Transporter 1 (Oat1) Substrates 4 ingredients

A pharmacology grouping from our source database: medications in this group share a property that certain supplements are known to interact with, so an interaction documented for the group applies to every drug in it.

4 of the supplement ingredients on this page reach Valacyclovir through this category.

About Valacyclovir

Valacyclovir is an antiviral medication used to treat herpes zoster (shingles) and genital herpes infections.

Generic name: Valacyclovir  ·  Brand name: Valtrex.

See the full Valacyclovir drug information
Check a real product

Take a Supplement Product? Check the Whole Bottle Against Valacyclovir

Most supplements are combination products — and the interaction may come from an ingredient you didn’t buy it for. Search any product below (or scan its label) and we’ll check every ingredient on it against Valacyclovir.

Search a supplement product

Type a product name, brand, or UPC — smart search across our full catalog.

Grounded search over our product catalog — every verdict comes from our interaction database, never AI guesswork. How we use AI

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Photograph any Supplement Facts panel — we read the ingredients and check each one against your medications. Free, in seconds.

Open the label scanner

Prefer typing? The interaction checker looks up products by name too.

Products that contain Valacyclovir-interacting ingredients

Real supplements from the NIH label database that contain the top interacting ingredients on this page — each one is worth a full label check before combining with Valacyclovir.

ModuProst by Nature's Harmony contains African Wild Potato
Pharmacist Counseling Corner

Valacyclovir & Supplements: Common Questions

What supplements interact with Valacyclovir?
Our database currently documents 27 ingredients with a known Valacyclovir interaction (1 major, 17 moderate, 9 minor). The practical move: scan the major group first, then look up the exact supplements you take rather than reading all 27. The highest-ranked right now: Activated Charcoal, Coffee Charcoal, European Mandrake.
Which Valacyclovir supplement interactions are the most serious?
The 1 major-rated combination — led by Activated Charcoal — deserve real caution: these are the ones generally best avoided, or used only with your prescriber watching. If you take any of them today, don't panic and don't stop anything abruptly — call your pharmacist first. Jump to the ranked list.
Can I take vitamins or supplements while on Valacyclovir?
Plenty of supplements coexist fine with Valacyclovir; a shorter list does not. Rather than memorizing it, check the specific ingredients on your labels — the ranked list above covers every one we've checked, and multi-ingredient products can be checked label-by-label with our scanner. Try the label scanner or the interaction checker.
Do brands like Valtrex have the same supplement interactions as Valacyclovir?
Yes — Valtrex all contain Valacyclovir, so everything on this page applies to them equally. Interactions belong to the active drug, never to the brand on the box; the same is true of generics.
Where do these interaction ratings come from?
Every rating comes from the Natural Medicines database — the same evidence-graded reference pharmacists and hospitals use — and each interaction carries three separate grades: severity (how bad it can be), likelihood (how well it's documented in studies and case reports), and an evidence level. Our pharmacists review the content; we never let an AI decide an interaction. See how to read the ratings and our editorial policy.
What about Valacyclovir and my other medications?
This page covers Valacyclovir against supplements and herbal ingredients. Checking Valacyclovir against your other prescription or OTC medications is a different tool — our drug interaction checker covers that side. Head to the drug–drug interaction checker, or read the full Valacyclovir drug information.

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

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Sourcing

Where This Data Comes From — and Why You Can Trust It

🧪 Licensed clinical database

Every interaction verdict on this page comes from Natural Medicines Pro (TRC Healthcare / Therapeutic Research) — the same evidence-graded reference used by pharmacists and hospitals. We license this data directly; we do not scrape it, and no AI invents an interaction.

🧑‍⚕️ Pharmacist review

This page is curated and coded by , Clinical Pharmacist, with additional analysis by the HelloPharmacist Pharmacist Team. Editorial commentary is ours; the licensed interaction records are shown as sourced.

🔄 Kept current

Our interaction database refreshes on a weekly cycle, and this page re-checks the live database every time it’s rebuilt — what you see reflects the database as of October 5, 2026.

🔍 Full transparency

How every dataset on this site is sourced, licensed, and updated is documented publicly: our data sources · editorial policy · how we use AI.

Educational information, not medical advice. An interaction being on file does not mean it will happen to you — and absence of one is not proof of safety. Never start or stop a medication or supplement without talking to your pharmacist or doctor.