Drug & supplement interaction

Fucus Vesiculosus + Semaglutide

Semaglutide brand names: Ozempic, Rybelsus, Wegovy.

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 Fucus Vesiculosus and Semaglutide 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

Fucus Vesiculosus and Semaglutide

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 Semaglutide and Fucus Vesiculosus 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.

Fucus Vesiculosus safety at a glance

Fucus Vesiculosus overall Use caution Variable, high iodine content can disrupt the thyroid and the plant may concentrate heavy metals.
Pregnancy Possibly Unsafe When used orally because it may contain iodine and heavy metals; avoid using. Read the full pregnancy detail
Breastfeeding Possibly Unsafe When used orally because it may contain iodine and heavy metals; avoid using. Read the full breastfeeding detail

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 Semaglutide and Fucus Vesiculosus? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Semaglutide

Interactions in our licensed database are recorded against drug classes, not just single drug names. Semaglutide is filed under 2 classifications — antidiabetes drugs, oral drugs. Fucus Vesiculosus has documented interactions with 9 drug classes — the most serious being amiodarone (cordarone) (moderate), antithyroid drugs (moderate) and lithium (moderate) — and none of Semaglutide’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

Fucus Vesiculosus Does Interact With Other Medications

Fucus Vesiculosus has 23 moderate, 868 minor known drug interactions in our database — Semaglutide isn’t one of them. If you take anything else, check it against the full list below.

Moderate 23 Minor 868 No known interaction 1,939 (incl. Semaglutide)
Taking anything else?

Check Another of Your Medications Against Fucus Vesiculosus

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

What to actually watch for

No Interaction Found — But Data Suggests Fucus Vesiculosus and Semaglutide 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. One of them is worth acting on rather than waiting out — marked below.

  • Kidney problems Worth acting on Additional detail

    Fucus Vesiculosus

    “A case of hemorrhagic cystitis characterized by dysuria and polyuria has been reported in a young adult who took a specific product (Slim-Kombu, Balestra and Mech) containing Fucus vesiculosus and 19 other herbal extracts orally for weight loss. Upon discontinuation, symptoms improved. It is unclear if this effect was due to Fucus vesiculosus or other ingredients in the supplement.”

    Fucus Vesiculosus · Natural Medicines adverse-effect record, reported in obesity.

    2 sources cited
    1. 46959. Catania, M. A., Oteri, A., Caiello, P., Russo, A., Salvo, F., Giustini, E. S., Caputi, A. P., and Polimeni, G. Hemorrhagic cystitis induced by an herbal mixture. South.Med.J. 2010;103(1):90-92. PubMed
    2. 12800. Conz PA, La Greca G, Benedetti P, et al. Fucus vesiculosus: a nephrotoxic alga? Nephrol Dial Transplant 1998;13:526-7.

    Semaglutide

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

Reported for Fucus Vesiculosus but not commonly for Semaglutide: an irregular heartbeat, a change in thyroid levels, a fast or pounding heartbeat and weight loss.

Effects for Semaglutide come from the ADVERSE REACTIONS section of its FDA label; effects for Fucus Vesiculosus 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

Fucus Vesiculosus in Pregnancy & Breastfeeding

Pregnancy And Lactation Possibly Unsafe

When used orally because it may contain iodine and heavy metals; 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

Overlapping uses

What Semaglutide Is Prescribed For, and What Fucus Vesiculosus Has Been Studied For

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

Semaglutide is prescribed for: Semaglutide is available as Wegovy (injection and tablet) and Ozempic (injection), and each product has its own approved uses. Wegovy injection is approved — alongside diet and exercise — to reduce excess body weight in adults and in children aged 12 and older with obesity, to lower the risk of serious heart events (heart attack, stroke, or cardiovascular death) in adults with obesity or overweight who also have established heart disease, and for treatment of a liver condition called MASH (metabolic dysfunction-associated steatohepatitis, formerly called NASH) with moderate-to-advanced scarring in adults. Wegovy tablets share the cardiovascular risk reduction and weight management uses in adults, but are not approved for MASH or for use in children. Ozempic injection is approved to improve blood sugar control in adults with type 2 diabetes (alongside diet and exercise) and to reduce the risk of major cardiovascular events in adults with type 2 diabetes who also have established heart disease.

Read the rest of what Semaglutide is prescribed for

All forms are used alongside a reduced-calorie diet and increased physical activity. Ozempic is not approved for type 1 diabetes. The MASH approval for Wegovy injection is an accelerated approval, meaning continued approval may depend on results from a confirmatory study.

Fucus Vesiculosus has been studied for:

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

    Fucus Vesiculosus for obesity

    Oral Fucus vesiculosus has only been evaluated in combination with other ingredients; its effect when used alone is unclear.

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 Semaglutide on your own; if you are taking Fucus Vesiculosus for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

From our Q&A

Questions About Fucus Vesiculosus or Semaglutide

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

This page covers Fucus Vesiculosus only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Semaglutide page lists 256 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Siberian Cocklebur (major), Acai (moderate), African Wild Potato (moderate) and Agaricus Mushroom (moderate).

By severity: 2 major · 215 moderate · 39 minor.

From our pharmacist’s overview on the Semaglutide page

“Semaglutide (Ozempic, Rybelsus, Wegovy) lowers blood sugar, and so do most of the 256 supplements on this page, which is why I read this list with real vigilance rather than a shrug. Nearly all of the entries either add to its glucose-lowering effect and raise the risk of hypoglycemia, or push sugar the other way and blunt it, as niaci…”

Reviewed by 2 · Jul 18, 2026

Open the Semaglutide interaction page

How much people look this up

Where Fucus Vesiculosus and Semaglutide 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 Fucus Vesiculosus
Steady interest

#1,020 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Semaglutide
Top 1%

#26 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 Fucus Vesiculosus reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Fucus Vesiculosus and Semaglutide 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 Fucus Vesiculosus

What is Fucus Vesiculosus?

Fucus Vesiculosus
  • Thyroid support
  • Iodine source
  • Weight management
  • Joint and skin care (topical)
  • Constipation and digestive support

Fucus vesiculosus (bladderwrack) is a brown seaweed rich in iodine that has been used traditionally for thyroid concerns, weight, and skin. There is little solid human evidence to support most of these uses, and its high and variable iodine content can actually harm the thyroid. Talk to a pharmacist or doctor before using it, especially if you have a thyroid condition.

Fucus vesiculosus · Fucaceae · Whole plant (thallus/dried seaweed) · Capsules, tablets, powder, tea, liquid extract, topical creams and gels

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

Fucus Vesiculosus: dosing

There is no well-established, standardized dose for bladderwrack, partly because its iodine content varies so much from product to product. This makes safe dosing very difficult to judge.If you choose to use it, follow the directions on the product label and do not exceed them.

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

Read the full Fucus Vesiculosus monograph & all interactions
Medication

About Semaglutide

What Is Semaglutide Used For?

Brand names: Ozempic, Rybelsus, Wegovy

Semaglutide is available as Wegovy (injection and tablet) and Ozempic (injection), and each product has its own approved uses. Wegovy injection is approved — alongside diet and exercise — to reduce excess body weight in adults and in children aged 12 and older with obesity, to lower the risk of serious heart events (heart attack, stroke, or cardiovascular death) in adults with obesity or overweight who also have established heart disease, and for treatment of a liver condition called MASH (metabolic dysfunction-associated steatohepatitis, formerly called NASH) with moderate-to-advanced scarring in adults. Wegovy tablets share the cardiovascular risk reduction and weight management uses in adults, but are not approved for MASH or for use in children. Ozempic injection is approved to improve blood sugar control in adults with type 2 diabetes (alongside diet and exercise) and to reduce the risk of major cardiovascular events in adults with type 2 diabetes who also have established heart disease.

All forms are used alongside a reduced-calorie diet and increased physical activity. Ozempic is not approved for type 1 diabetes. The MASH approval for Wegovy injection is an accelerated approval, meaning continued approval may depend on results from a confirmatory study.

See full Semaglutide drug information
Keep checking

Other Drugs & Fucus Vesiculosus

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

0Major
23Moderate
868Minor
1,938No known interaction
23 Moderate 868 Minor 1,938 No interaction
Moderate

23 interactions

Minor

868 interactions

Showing 60 of 868 minor interactions — see all 868 on the Fucus Vesiculosus page.

No interaction 1,938 drugs checked — show the list

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

Showing the 60 most looked-up of 1,938 medications checked with no known interaction — see the full Fucus Vesiculosus list.

See the full Fucus Vesiculosus interactions page
See every supplement checked against Semaglutide, ranked by severity
Evidence & sources

Fucus Vesiculosus References

The 15 references that drive our Fucus Vesiculosus 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. Goodman GA, Rall TW, Nies AS, Taylor P. The Pharmacological Basis of Therapeutics, 9th ed.
  2. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, DC: National Academy Press, 2002.
  3. Phaneuf D, Cote I, Dumas P, et al. Evaluation of the contamination of marine algae (Seaweed) from the St. Lawrence River and likely to be consumed by humans. Environ Res 1999;80:S175-S182. PubMed
  4. Durig J, Bruhn T, Zurborn KH, et al. Anticoagulant fucoidan fractions from Fucus vesiculosus induce platelet activation in vitro. Thromb Res 1997;85:479-91. PubMed
  5. Conz PA, La Greca G, Benedetti P, et al. Fucus vesiculosus: a nephrotoxic alga? Nephrol Dial Transplant 1998;13:526-7.
  6. Ohye H, Fukata S, Kanoh M, et al. Thyrotoxicosis caused by weight-reducing herbal medicines. Arch Intern Med 2005;165:831-4. PubMed
  7. Okamura K, Inoue K, Omae T. A case of Hashimoto's thyroiditis with thyroid immunological abnormality manifested after habitual ingestion of seaweed. Acta Endocrinol (Copenh) 1978;88:703-12. PubMed
  8. Agarwal SC, Crook JR, Pepper CB. Herbal remedies -- how safe are they? A case report of polymorphic ventricular tachycardia/ventricular fibrillation induced by herbal medication used for obesity. Int J Cardiol 2006;106:260-1. PubMed
  9. Sterling JB, Heymann WR. Potassium iodide in dermatology: a 19th century drug for the 21st century-uses, pharmacology, adverse effects, and contraindications. J Am Acad Dermatol 2000;43:691-7. PubMed
  10. Catania, M. A., Oteri, A., Caiello, P., Russo, A., Salvo, F., Giustini, E. S., Caputi, A. P., and Polimeni, G. Hemorrhagic cystitis induced by an herbal mixture. South.Med.J. 2010;103(1):90-92. PubMed
  11. Cumashi, A., Ushakova, N. A., Preobrazhenskaya, M. E., D'Incecco, A., Piccoli, A., Totani, L., Tinari, N., Morozevich, G. E., Berman, A. E., Bilan, M. I., Usov, A. I., Ustyuzhanina, N. E., Grachev, A. A., Sanderson, C. J., Kelly, M., Rabinovich, G. A., I
  12. Irhimeh, M. R., Fitton, J. H., and Lowenthal, R. M. Pilot clinical study to evaluate the anticoagulant activity of fucoidan. Blood Coagul.Fibrinolysis 2009;20(7):607-610. PubMed
  13. Arbaizar, B. and Llorca, J. [Fucus vesiculosus induced hyperthyroidism in a patient undergoing concomitant treatment with lithium]. Actas Esp.Psiquiatr. 2011;39(6):401-403.
  14. Church FC, Meade JB, Treanor RE, and et al. Antithrombin activity of fucoidan. The interaction of fucoidan with heparin cofactor II, antithrombin III, and thrombin. J Biol Chem 2-25-1989;264(6):3618-3623. DOI
  15. Mathew L, Burney M, Gaikwad A, et al. Preclinical evaluation of safety of fucoidan extracts from Undaria pinnatifida and Fucus vesiculosus for use in cancer treatment. Integr Cancer Ther 2017;16(4):572-84.

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 Fucus Vesiculosus and Semaglutide Together: Common Questions

Is it safe to take Fucus Vesiculosus with Semaglutide?
We do not list a known interaction between Fucus Vesiculosus and Semaglutide. 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 Fucus Vesiculosus and Semaglutide 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.
Are Fucus Vesiculosus and Semaglutide 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 Fucus Vesiculosus in each. That is a conversation for your prescriber, especially if Semaglutide is being adjusted to a target.
How was the Fucus Vesiculosus and Semaglutide combination checked?
Interactions in our licensed database are recorded against drug classes. Semaglutide is filed under 2 classifications, and Fucus Vesiculosus has documented interactions with 9 drug classes — none of Semaglutide'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 Fucus Vesiculosus interact with any other medications?
Yes. Fucus Vesiculosus has 891 documented drug interactions in our database — Semaglutide 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 Semaglutide interact with any supplements?
Yes. Semaglutide has documented interactions with 256 supplements in our database — Fucus Vesiculosus is not one of them. The Semaglutide 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

Fucus Vesiculosus monograph Uses, safety profile, and every drug interaction in one place Semaglutide drug information The full plain-English guide to this medication Semaglutide supplement interactions Every supplement checked against Semaglutide, 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 15 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Semaglutide and Fucus Vesiculosus?

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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.