Drug & supplement interaction

Fulvic Acid + Vandetanib

Vandetanib brand name: Caprelsa.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Fulvic Acid and Vandetanib 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 Vandetanib

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 Vandetanib 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 Vandetanib and Fulvic Acid? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Vandetanib

Interactions in our licensed database are recorded against drug classes, not just single drug names. Vandetanib is filed under 3 classifications — qt interval-prolonging drugs, cytochrome p450 3a4 (cyp3a4) substrates, oral drugs. 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 Vandetanib’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 — Vandetanib 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. Vandetanib)
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 Vandetanib 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.

  • Diarrhea / Sore throat reported in 18.3% of FDA reports for Vandetanib 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

    Vandetanib

    Listed in the ADVERSE REACTIONS section of the FDA label for Vandetanib, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

  • Headache Additional detail

    Fulvic Acid

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

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

    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

    Vandetanib

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

Effects for Vandetanib 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 1,773 voluntary FDA FAERS reports for Vandetanib 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.

Overlapping uses

What Vandetanib Is Prescribed For, and What Fulvic Acid Has Been Studied For

These two come up together because they touch the same health topic — not because they do the same job. Vandetanib is a prescription medicine with approved uses on its FDA label. Fulvic Acid is a supplement: what follows is what researchers have looked at it for, and how strong that evidence is.

Vandetanib is prescribed for: Caprelsa (vandetanib) is used to treat medullary thyroid cancer — a type of thyroid cancer — in adults whose tumor cannot be surgically removed or has spread (locally advanced or metastatic disease) and is causing symptoms or actively growing. Caprelsa should be used with extra caution in patients whose cancer is slow-growing and not causing symptoms, because the serious risks of the medicine must be carefully weighed against any potential benefit in that setting.

Fulvic Acid has been studied for:

  • Cancer studied, not established Fulvic Acid has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

    Fulvic Acid for cancer

    Although there has been interest in using oral fulvic acid for cancer, there is insufficient reliable information about the clinical effects of fulvic acid for this purpose.

Effectiveness ratings and the research summaries above are the verbatim record from the Natural Medicines database, which grades evidence from “Effective” down to “Insufficient Reliable Evidence To Rate”. A rating below the top of that scale means researchers have looked at it — not that it works, and never that it can stand in for a prescribed medicine. Do not stop or replace Vandetanib on your own; if you are taking Fulvic Acid for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

Everything else you take

See Every Supplement That Interacts With Vandetanib

This page covers Fulvic Acid only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Vandetanib page lists 146 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), Cesium (major) and Ephedra (major).

By severity: 8 major · 98 moderate · 40 minor.

From our pharmacist’s overview on the Vandetanib page

“Vandetanib (Caprelsa) treats medullary thyroid cancer and already carries a boxed warning for heart rhythm problems, so I read this list of 146 ingredients with real wariness rather than a shrug. Most of it, 121 ingredients, ties back to CYP3A4, the liver enzyme that clears vandetanib.”

Reviewed by 2 · Jul 18, 2026

Open the Vandetanib 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 Vandetanib, 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 Vandetanib 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

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

29 days ago today
Medication Vandetanib
Steady interest

#1,984 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 20, 2026. The Fulvic Acid and Vandetanib 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 Vandetanib

What Is Vandetanib Used For?

Brand name: Caprelsa

Caprelsa (vandetanib) is used to treat medullary thyroid cancer — a type of thyroid cancer — in adults whose tumor cannot be surgically removed or has spread (locally advanced or metastatic disease) and is causing symptoms or actively growing.

Caprelsa should be used with extra caution in patients whose cancer is slow-growing and not causing symptoms, because the serious risks of the medicine must be carefully weighed against any potential benefit in that setting.

Most-Reported Side Effects for Vandetanib

From FAERS, the FDA’s public side-effect reporting system (1,794 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Diarrhea 329 reports
Rash 176 reports
Fatigue 175 reports
Electrocardiogram qt prolonged 142 reports
Hypertension 115 reports
See full Vandetanib 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 Vandetanib, 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 Vandetanib Together: Common Questions

Is it safe to take Fulvic Acid with Vandetanib?
We do not list a known interaction between Fulvic Acid and Vandetanib. 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 Vandetanib have any of the same side effects?
Yes — our sources link each of them separately to 3 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.
Are Fulvic Acid and Vandetanib used for the same thing?
They overlap in purpose, which usually means the real question is whether you need both rather than whether they are safe together. This page lists the shared uses and how strong the evidence is for Fulvic Acid in each. That is a conversation for your prescriber, especially if Vandetanib is being adjusted to a target.
How was the Fulvic Acid and Vandetanib combination checked?
Interactions in our licensed database are recorded against drug classes. Vandetanib is filed under 3 classifications, and Fulvic Acid has documented interactions with 3 drug classes — none of Vandetanib'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 — Vandetanib 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 Vandetanib interact with any supplements?
Yes. Vandetanib has documented interactions with 146 supplements in our database — Fulvic Acid is not one of them. The Vandetanib 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 Vandetanib drug information The full plain-English guide to this medication Vandetanib supplement interactions Every supplement checked against Vandetanib, 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 Vandetanib 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.