Drug & supplement interaction

Fulvic Acid + Tizanidine

Tizanidine brand names: Zanaflex, Ontralfy.

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 Fulvic Acid and Tizanidine 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 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

Fulvic Acid and Tizanidine

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 Tizanidine and Fulvic Acid 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.

Fulvic Acid safety at a glance

Fulvic Acid overall Use caution Short-term use appears generally tolerated, but high-quality safety data in humans is limited.
Pregnancy Avoid There is not enough safety information, so avoid use during pregnancy.
Breastfeeding Avoid There is not enough safety information, so avoid use while breastfeeding.

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

Still wondering about combining Tizanidine and Fulvic Acid? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Tizanidine

Interactions in our licensed database are recorded against drug classes, not just single drug names. Tizanidine is filed under 6 classifications — including skeletal muscle relaxants, qt interval-prolonging drugs, cytochrome p450 1a2 (cyp1a2) substrates. Fulvic Acid has documented interactions with 3 drug classes — the most serious being anticoagulant/antiplatelet drugs (moderate), immunosuppressants (moderate) and thyroid hormone (moderate) — and none of Tizanidine’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

Fulvic Acid Does Interact With Other Medications

Fulvic Acid has 257 moderate known drug interactions in our database — Tizanidine isn’t one of them. If you take anything else, check it against the full list below.

Moderate 257 No known interaction 2,573 (incl. Tizanidine)
Taking anything else?

Check Another of Your Medications Against Fulvic Acid

Covers the 2,830 medications we’ve checked against Fulvic Acid. Pick one to open its full report.

What to actually watch for

No Interaction Found — But Data Suggests Fulvic Acid and Tizanidine May Share a Side Effect

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.

  • Sore throat Additional detail

    Fulvic Acid

    “In one clinical trial, fulvic acid 3.8% 40 mL taken orally twice daily resulted in diarrhea and sore throat in some patients.”

    Fulvic Acid · Natural Medicines adverse-effect record, reported in diarrhea.

    1 source cited
    1. 90589. Gandy JJ, Meeding JP, Snyman JR, et al. Phase 1 clinical study of the acute and subacute safety and proof-of-concept efficacy of carbohydrate-derived fulvic acid. Clin Pharmacol. 2012;4:7-11. PubMed

    Tizanidine

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

Reported for Fulvic Acid but not commonly for Tizanidine: diarrhea and headache.

Effects for Tizanidine come from the ADVERSE REACTIONS section of its FDA label; effects for Fulvic Acid come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 40,365 voluntary FDA FAERS reports for Tizanidine that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

From our Q&A

Questions About Fulvic Acid or Tizanidine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Fulvic Acid or Tizanidine, 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 Tizanidine

This page covers Fulvic Acid only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Tizanidine page lists 143 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), Arsenic (major), Beer (major) and Cesium (major).

By severity: 11 major · 101 moderate · 31 minor.

Open the Tizanidine interaction page

One more smart check

Taking Fulvic Acid as Part of a Dietary Supplement Product? Check It for Interactions

We hold 294 real supplement products containing Fulvic Acid, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Fulvic Acid. Even though Fulvic Acid itself has no known interaction with Tizanidine, 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 Fulvic Acid and Tizanidine 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 Fulvic Acid
Top half

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

29 days ago today
Medication Tizanidine
Steady interest

#1,823 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 Fulvic Acid reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Fulvic Acid and Tizanidine 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 Fulvic Acid

What is Fulvic Acid?

  • General wellness and energy
  • Gut health
  • Antioxidant support
  • Mineral and nutrient supplementation
  • Immune support

Fulvic acid is a natural compound formed when plants and microbes break down in soil, and it is sold as a supplement for energy, gut, and overall wellness. Human research is very limited, so most claims are unproven. Talk with your pharmacist or doctor before using it, and avoid it during pregnancy and breastfeeding due to a lack of safety data.

Derived from humus, soil, peat, and decomposed plant matter (often sourced from shilajit or leonardite) · Liquid drops, capsules, powders, shilajit resin, mineral supplements

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

Fulvic Acid: dosing

There is no official or standardized dose for fulvic acid. Products vary widely in concentration and form, including drops, capsules, and powders.The safest approach is to follow the directions on the product label and start with the lowest suggested amount.

From our Fulvic Acid monograph — the full record covers uses, side effects and every documented interaction.

Read the full Fulvic Acid monograph & all interactions
Medication

About Tizanidine

What Is Tizanidine Used For?

Brand names: Zanaflex, Ontralfy

Tizanidine — available as tablets, capsules, and as the oral solution Ontralfy — is used to manage spasticity (abnormal muscle stiffness or spasms). Because it works for a relatively short window of time, it is typically scheduled around the activities when spasm relief matters most.

Ontralfy (oral solution) and Zanaflex capsules are specifically indicated for the treatment of spasticity in adults. Other tizanidine tablets and capsules are indicated for the management of spasticity more broadly.

Most-Reported Side Effects for Tizanidine

From FAERS, the FDA’s public side-effect reporting system (41,177 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Fatigue 3,191 reports
Nausea 3,007 reports
Headache 2,695 reports
Fall 2,309 reports
Diarrhea 1,970 reports
See full Tizanidine drug information
Keep checking

Other Drugs & Fulvic Acid

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

0Major
257Moderate
0Minor
2,572No known interaction
257 Moderate 2,572 No interaction
Moderate

257 interactions

Showing 60 of 257 moderate interactions — see all 257 on the Fulvic Acid page.

No interaction 2,572 drugs checked — show the list

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

Showing the 60 most looked-up of 2,572 medications checked with no known interaction — see the full Fulvic Acid list.

See the full Fulvic Acid interactions page
See every supplement checked against Tizanidine, ranked by severity
Evidence & sources

Fulvic Acid References

The 3 references that drive our Fulvic Acid 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. Lu, FJ. Arsenic as a promoter in the effect of humic substances on plasma prothrombin time in vitro. Thromb Res 6-15-1990;58(6):537-541. PubMed
  2. Vucskits, AV, Hullar, I, Bersenyi, A, Andrasofszky, E, Kulcsar, M, Szabo, J. Effect of fulvic and humic acids on performance, immune response and thyroid function in rats. J Anim Physiol Anim Nutr (Berl) 2010;94(6):721-728. PubMed
  3. Gandy JJ, Meeding JP, Snyman JR, et al. Phase 1 clinical study of the acute and subacute safety and proof-of-concept efficacy of carbohydrate-derived fulvic acid. Clin Pharmacol. 2012;4:7-11. 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 Fulvic Acid and Tizanidine Together: Common Questions

Is it safe to take Fulvic Acid with Tizanidine?
We do not list a known interaction between Fulvic Acid and Tizanidine. 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 Fulvic Acid and Tizanidine have any of the same side effects?
Yes — our sources link each of them separately to one 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.
How was the Fulvic Acid and Tizanidine combination checked?
Interactions in our licensed database are recorded against drug classes. Tizanidine is filed under 6 classifications, and Fulvic Acid has documented interactions with 3 drug classes — none of Tizanidine'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 Fulvic Acid interact with any other medications?
Yes. Fulvic Acid has 257 documented drug interactions in our database — Tizanidine 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 Tizanidine interact with any supplements?
Yes. Tizanidine has documented interactions with 143 supplements in our database — Fulvic Acid is not one of them. The Tizanidine 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

Fulvic Acid monograph Uses, safety profile, and every drug interaction in one place Tizanidine drug information The full plain-English guide to this medication Tizanidine supplement interactions Every supplement checked against Tizanidine, 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 3 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Tizanidine and Fulvic Acid?

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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.