Drug & supplement interaction

Fucus Vesiculosus + Mometasone, formoterol

Mometasone, formoterol brand name: Zenhale.

Minor Interaction
Medically reviewed by · Updated September 2026
The bottom line Minor

Mometasone, formoterol falls into 3 drug categories that Fucus Vesiculosus can interact with; the most serious is rated minor. Theoretically, concomitant use of Fucus vesiculosus with CYP2D6 substrates might alter the effects of these substrates.

Read the full interaction report
SeverityMinor
LikelihoodPossible
Interactions3
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Fucus Vesiculosus and Mometasone, formoterol

These two interact in 3 distinct ways. Each one is explained separately below.

Why Are There 3 Interactions?

Fucus Vesiculosus interacts with whole categories of medication. Mometasone, formoterol falls into 3 of those categories, so it can interact with Fucus Vesiculosus in 3 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Minor).

Minor

CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES

1 of 3

Why this applies to Mometasone, formoterol

Mometasone, formoterol falls under CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES — the group Fucus Vesiculosus interacts with.

Theoretically, concomitant use of Fucus vesiculosus with CYP2D6 substrates might alter the effects of these substrates.
In vitro research shows that fucoidan, a constituent of Fucus vesiculosus, both inhibits and induces CYP2D6. This interaction has not been reported in humans.
Severity Minor Likelihood Possible Evidence D

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.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the honest picture with bladderwrack and your Zenhale inhaler (mometasone plus formoterol). The concern on file is that a compound in bladderwrack called fucoidan might nudge a liver enzyme called CYP2D6, which can play a small role in clearing formoterol. The catch is this comes only from lab dish studies, and the seaweed seemed to both speed up and slow down that enzyme, so we can't even say which direction it would go in a real person. It has never actually been reported in people.

On top of that, your inhaler is breathed into the lungs, so very little reaches your bloodstream to begin with. I'd rate this as low concern. The bigger reason to check with your doctor before bladderwrack is its iodine load and your thyroid.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. 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.
Minor

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES

2 of 3

Mometasone, formoterol also falls under CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES.

Theoretically, concomitant use of Fucus vesiculosus with CYP2C9 substrates might increase the risk for adverse effects.
In vitro research shows that fucoidan, a constituent of Fucus vesiculosus, inhibits CYP2C9. This interaction has not been reported in humans.
Severity Minor Likelihood Possible Evidence D

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.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Let me put your mind at ease a bit here. Zenhale is an inhaler that combines two medicines: mometasone (a steroid that calms airway swelling) and formoterol (a long-acting reliever that opens the airways). The concern on file is that a compound in bladderwrack (fucoidan) might slow down a liver enzyme called CYP2C9, which could in theory let a little more of the medicine linger in your body. If that happened, you might notice more of the usual side effects, like a fast or pounding heartbeat, jitteriness, shakiness, or a headache.

That said, this is purely lab-dish research, not anything seen in real people, and it's rated minor. Most of an inhaler stays in your lungs, so the effect is likely tiny. Still, with bladderwrack's iodine and your thyroid in mind, I'd run it past your pharmacist before starting it.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. 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.
Minor

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

3 of 3

Mometasone, formoterol also falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES.

Theoretically, concomitant use of Fucus vesiculosus with CYP3A4 substrates might increase the risk for adverse effects.
In vitro research shows that fucoidan, a constituent of Fucus vesiculosus, inhibits CYP3A4. This interaction has not been reported in humans.
Severity Minor Likelihood Possible Evidence D

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.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Zenhale combines two medicines you breathe in: mometasone (an inhaled steroid) and formoterol (a long-acting airway opener). Both are partly broken down by a liver enzyme called CYP3A4. In a test-tube study, fucoidan from bladderwrack slowed that same enzyme down. In theory, that could let a bit more of your inhaler's medicine linger in your body.

Here's the honest part: this has only been seen in the lab, never in real people, and it's rated a minor, possible interaction. If it did matter at all, you might notice slightly more steroid effects or formoterol jitters like a faster heartbeat, shaky hands, or feeling wired. It's unlikely to be a problem, but since bladderwrack can also upset your thyroid, it's worth a quick chat with your pharmacist before starting it.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. 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.

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction 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.
  • PossibleInteraction 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.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Fucus Vesiculosus Also Interacts With Other Medications

Fucus Vesiculosus has 23 moderate, 867 minor known drug interactions in our database — the Mometasone, formoterol one above is among them. If you take anything else, check it against the full list below.

Moderate 23 Minor 867 No known interaction 1,940 (incl. Mometasone, formoterol)
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.

Everything else you take

See Every Supplement That Interacts With Mometasone, formoterol

This page covers Fucus Vesiculosus only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Mometasone, formoterol page lists 155 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Grapefruit (major), St. John's Wort (major), 1,3-dmaa (moderate), Acacia Rigidula (moderate) and Active Hexose Correlated Compound (ahcc) (moderate).

By severity: 2 major · 120 moderate · 33 minor.

From our pharmacist’s overview on the Mometasone, formoterol page

“Mometasone and formoterol (Zenhale) is an inhaled asthma controller, a steroid paired with a long-acting airway opener, and its supplement list calls for real vigilance rather than a shrug. Nearly everything on it acts on the liver enzymes that break these medicines down, chiefly one called CYP3A4.”

Reviewed by 2 · Jul 18, 2026

Open the Mometasone, formoterol interaction page

How much people look this up

Where Fucus Vesiculosus and Mometasone, formoterol 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

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

29 days ago today
Medication Mometasone, formoterol
Steady interest

#2,307 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.

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.

Read the full Fucus Vesiculosus monograph & all interactions
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
867Minor
1,939No known interaction
23 Moderate 867 Minor 1,939 No interaction
Moderate

23 interactions

Minor

867 interactions

Showing 60 of 867 minor interactions — see all 867 on the Fucus Vesiculosus page.

No interaction 1,939 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 1,939 medications checked with no known interaction — see the full Fucus Vesiculosus list.

See the full Fucus Vesiculosus interactions page
See every supplement checked against Mometasone, formoterol, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Fucus Vesiculosus monograph › Uses, safety, and every drug interaction in one place Mometasone, formoterol supplement interactions › Every supplement checked against Mometasone, formoterol, 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 Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Fucus Vesiculosus and Mometasone, formoterol Together: Common Questions

Can you take Fucus Vesiculosus with Mometasone, formoterol?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
Why are there 3 interactions listed for Fucus Vesiculosus and Mometasone, formoterol?
Mometasone, formoterol belongs to more than one drug category, and Fucus Vesiculosus interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Fucus Vesiculosus and Mometasone, formoterol interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

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

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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.