Drug & supplement interaction

Collagen Type Ii (native) + Fexofenadine

Fexofenadine brand name: Allegra.

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 Collagen Type Ii (native) and Fexofenadine 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.

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Interaction report

Collagen Type Ii (native) and Fexofenadine

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 Fexofenadine and Collagen Type Ii (native) 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.

Worth understanding: our licensed dataset holds no drug-interaction record for Collagen Type Ii (native) at all — not against Fexofenadine, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

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.

Collagen Type Ii (native) safety at a glance

Collagen Type Ii (... overall Use caution Generally well tolerated in studies, but long-term safety data are limited.
Pregnancy Avoid Not enough safety information, so it is best avoided during pregnancy.
Breastfeeding Avoid Not enough safety information, so it is best avoided while breastfeeding.

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

Still wondering about combining Fexofenadine and Collagen Type Ii (native)? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

What Collagen Type Ii (native) Itself Has Been Linked To

This is not an interaction — nothing below involves Fexofenadine. It is the side-effect record for Collagen Type Ii (native) on its own, from the licensed Natural Medicines monograph. If something new turns up after you add Collagen Type Ii (native), this list is the first place to look. One entry is worth acting on rather than waiting out — marked below.

  • Raised blood pressure Worth acting on Additional detail

    “Orally, one incident of mild hypertension was reported as being possibly related to collagen type II in a clinical trial of children.”

    Collagen Type Ii (native) · Natural Medicines adverse-effect record, reported in hypertension.

    1 source cited
    1. 101719. Thompson DJ, Barron KS, Whitcup SM, Robinson MR. The safety and efficacy of chicken type II collagen on uveitis associated with juvenile rheumatoid arthritis. Ocul Immunol Inflamm. 2002;10(2):83-91. PubMed
  • Reduced appetite Additional detail

    “Orally, the most common adverse effects of collagen type II reported in clinical studies are gastrointestinal and include constipation, nausea, vomiting, and abdominal pain. These occurred in up to 7% of patients taking collagen type II. Anorexia was also reported, but this was much less common.”

    Collagen Type Ii (native) · Natural Medicines adverse-effect record, reported in anorexia.

    1 source cited
    1. 44451. Zhang, L. L., Wei, W., Xiao, F., Xu, J. H., Bao, C. D., Ni, L. Q., and Li, X. F. A randomized, double-blind, multicenter, controlled clinical trial of chicken type II collagen in patients with rheumatoid arthritis. Arthritis Rheum 7-15-2008;59(7):905-910 PubMed
  • Trouble sleeping / Dizziness Additional detail

    “Orally, headache, dizziness, and insomnia have been reported for patients taking collagen type II in clinical studies, but these events are uncommon.”

    Collagen Type Ii (native) · Natural Medicines adverse-effect record, reported in cluster headache.

    4 sources cited
    1. 44451. Zhang, L. L., Wei, W., Xiao, F., Xu, J. H., Bao, C. D., Ni, L. Q., and Li, X. F. A randomized, double-blind, multicenter, controlled clinical trial of chicken type II collagen in patients with rheumatoid arthritis. Arthritis Rheum 7-15-2008;59(7):905-910 PubMed
    2. 97238. Crowley DC, Lau FC, Sharma P, Evans M, Guthrie N, Bagchi M, et al Safety and efficacy of undenatured type II collagen in the treatment of osteoarthritis of the knee: a clinical trial. Int J Med Sci. 2009 Oct 9;6(6):312-21. PubMed
    3. 97239. Lugo JP, Saiyed ZM, Lane NE. Efficacy and tolerability of an undenatured type II collagen supplement in modulating knee osteoarthritis symptoms: a multicenter randomized, double-blind, placebo-controlled study.Nutr J. 2016;15:14. doi: 10.1186/s12937-016-0 PubMed
    4. 101717. Wei W, Zhang LL, Xu JH, et al. A multicenter, double-blind, randomized, controlled phase III clinical trial of chicken type II collagen in rheumatoid arthritis. Arthritis Res Ther. 2009;11(6):R180. PubMed
  • Constipation / Stomach pain / Vomiting Additional detail

    “Orally, collagen type II seems to be well tolerated.

    Most Common Adverse Effects:

    Orally: Abdominal pain, constipation, nausea, and vomiting.”

    Collagen Type Ii (native) · Natural Medicines adverse-effect record, reported in constipation.

  • Itching / A skin rash Additional detail

    “Orally, collagen type II might cause itching. In two cases, the itching was associated with skin eruption.”

    Collagen Type Ii (native) · Natural Medicines adverse-effect record, reported in pruritus.

    3 sources cited
    1. 44451. Zhang, L. L., Wei, W., Xiao, F., Xu, J. H., Bao, C. D., Ni, L. Q., and Li, X. F. A randomized, double-blind, multicenter, controlled clinical trial of chicken type II collagen in patients with rheumatoid arthritis. Arthritis Rheum 7-15-2008;59(7):905-910 PubMed
    2. 101717. Wei W, Zhang LL, Xu JH, et al. A multicenter, double-blind, randomized, controlled phase III clinical trial of chicken type II collagen in rheumatoid arthritis. Arthritis Res Ther. 2009;11(6):R180. PubMed
    3. 101719. Thompson DJ, Barron KS, Whitcup SM, Robinson MR. The safety and efficacy of chicken type II collagen on uveitis associated with juvenile rheumatoid arthritis. Ocul Immunol Inflamm. 2002;10(2):83-91. PubMed
  • Swelling Additional detail

    “Orally, edema occurred in two patients taking collagen type II in clinical research.”

    Collagen Type Ii (native) · Natural Medicines adverse-effect record, reported in pregnancy-related edema.

    1 source cited
    1. 101717. Wei W, Zhang LL, Xu JH, et al. A multicenter, double-blind, randomized, controlled phase III clinical trial of chicken type II collagen in rheumatoid arthritis. Arthritis Res Ther. 2009;11(6):R180. PubMed

Showing the 10 most notable of 12 recorded effects — ranked by how unusual each one is across medicines generally, with serious effects weighted up.

Everything above comes from the Natural Medicines adverse-effect record for Collagen Type Ii (native) — expand a row for the licensed statement it rests on. We haven’t matched Fexofenadine to its FDA label in our system yet, so we can’t compare its own side-effect list here — the leaflet that comes with your prescription is the authoritative list for Fexofenadine.

Overlapping uses

What Fexofenadine Is Prescribed For, and What Collagen Type Ii (native) Has Been Studied For

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

Fexofenadine is prescribed for: Fexofenadine temporarily relieves symptoms of hay fever (seasonal allergic rhinitis) and other upper respiratory allergies, including runny nose, sneezing, itchy or watery eyes, and itching of the nose or throat. Several products — including Allegra Hives 24hr tablets — are specifically used to reduce hives (urticaria) and relieve the itching that comes with them. Keep in mind that fexofenadine will not prevent hives or stop an allergic skin reaction from happening in the first place.

Collagen Type Ii (native) has been studied for:

  • Urticaria studied, not established Collagen Type Ii (native) has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

    Collagen Type Ii (native) for urticaria

    Although there has been interest in using oral collagen type II for urticaria associated with stress, there is insufficient reliable information about the clinical effects of collagen type II for this condition.

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 Fexofenadine on your own; if you are taking Collagen Type Ii (native) for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

From our Q&A

Questions About Collagen Type Ii (native) or Fexofenadine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Collagen Type Ii (native) or Fexofenadine, 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 Fexofenadine

This page covers Collagen Type Ii (native) only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Fexofenadine page lists 154 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Apple (major), Grapefruit (major), St. John's Wort (major) and Sweet Orange (major).

By severity: 5 major · 111 moderate · 38 minor.

From our pharmacist’s overview on the Fexofenadine page

“An over-the-counter allergy pill sounds like the last place serious interactions would hide, but fexofenadine (Allegra) has 154 supplements and foods on file, and the five rated major deserve real attention before you combine it with much of anything else. Two of those five sit in most refrigerators.”

Reviewed by 2 · Jul 18, 2026

Open the Fexofenadine interaction page

How much people look this up

Where Collagen Type Ii (native) and Fexofenadine 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 Collagen Type Ii (native)
Steady interest

#1,212 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Fexofenadine
Steady interest

#1,458 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 Collagen Type Ii (native) reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Collagen Type Ii (native) and Fexofenadine 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 Collagen Type Ii (native)

What is Collagen Type Ii (native)?

  • Osteoarthritis and joint pain
  • Joint comfort and mobility
  • Rheumatoid arthritis
  • Exercise-related joint discomfort
  • Joint support in active adults

Native (undenatured) type II collagen is a protein from cartilage, usually chicken, taken in small amounts to support joints, especially in osteoarthritis. Some early research is promising, but the overall evidence is still limited and not conclusive. It appears generally well tolerated, but talk with your pharmacist or doctor before starting it.

Cartilage (often from chicken sternum); collagen protein isolated from cartilage · Capsules, tablets, powders (often labeled UC-II or 'undenatured type II collagen')

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

Collagen Type Ii (native): dosing

There is no official standardized dose, but native type II collagen is unusual because it is used in very small daily amounts — far smaller than typical collagen peptide powders. The exact amount depends on the specific product.The best approach is to follow the directions on the product label and not assume more is better.

From our Collagen Type Ii (native) monograph — the full record covers uses, side effects and every documented interaction.

Read the full Collagen Type Ii (native) monograph & all interactions
Medication

About Fexofenadine

What Is Fexofenadine Used For?

Brand name: Allegra

Fexofenadine temporarily relieves symptoms of hay fever (seasonal allergic rhinitis) and other upper respiratory allergies, including runny nose, sneezing, itchy or watery eyes, and itching of the nose or throat.

Several products — including Allegra Hives 24hr tablets — are specifically used to reduce hives (urticaria) and relieve the itching that comes with them. Keep in mind that fexofenadine will not prevent hives or stop an allergic skin reaction from happening in the first place.

Most-Reported Side Effects for Fexofenadine

From FAERS, the FDA’s public side-effect reporting system (40,472 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Fatigue 1,945 reports
Nausea 1,876 reports
Headache 1,870 reports
Pruritus 1,733 reports
Diarrhea 1,622 reports
See full Fexofenadine drug information
Keep checking

Other Drugs & Collagen Type Ii (native)

Browse every other medication we’ve checked against Collagen Type Ii (native) — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
0Moderate
0Minor
2,829No known interaction
2,829 No interaction
No interaction 2,829 drugs checked — show the list

We also checked Collagen Type Ii (native) against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Collagen Type Ii (native) list.

See the full Collagen Type Ii (native) interactions page
See every supplement checked against Fexofenadine, ranked by severity
Evidence & sources

Collagen Type Ii (native) References

The 5 references that drive our Collagen Type Ii (native) 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. Zhang, L. L., Wei, W., Xiao, F., Xu, J. H., Bao, C. D., Ni, L. Q., and Li, X. F. A randomized, double-blind, multicenter, controlled clinical trial of chicken type II collagen in patients with rheumatoid arthritis. Arthritis Rheum 7-15-2008;59(7):905-910 PubMed
  2. Crowley DC, Lau FC, Sharma P, Evans M, Guthrie N, Bagchi M, et al Safety and efficacy of undenatured type II collagen in the treatment of osteoarthritis of the knee: a clinical trial. Int J Med Sci. 2009 Oct 9;6(6):312-21. PubMed
  3. Lugo JP, Saiyed ZM, Lane NE. Efficacy and tolerability of an undenatured type II collagen supplement in modulating knee osteoarthritis symptoms: a multicenter randomized, double-blind, placebo-controlled study.Nutr J. 2016;15:14. doi: 10.1186/s12937-016-0 PubMed
  4. Wei W, Zhang LL, Xu JH, et al. A multicenter, double-blind, randomized, controlled phase III clinical trial of chicken type II collagen in rheumatoid arthritis. Arthritis Res Ther. 2009;11(6):R180. PubMed
  5. Thompson DJ, Barron KS, Whitcup SM, Robinson MR. The safety and efficacy of chicken type II collagen on uveitis associated with juvenile rheumatoid arthritis. Ocul Immunol Inflamm. 2002;10(2):83-91. 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 Collagen Type Ii (native) and Fexofenadine Together: Common Questions

Is it safe to take Collagen Type Ii (native) with Fexofenadine?
We do not list a known interaction between Collagen Type Ii (native) and Fexofenadine. 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.
Are Collagen Type Ii (native) and Fexofenadine 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 Collagen Type Ii (native) in each. That is a conversation for your prescriber, especially if Fexofenadine is being adjusted to a target.
Does Fexofenadine interact with any supplements?
Yes. Fexofenadine has documented interactions with 154 supplements in our database — Collagen Type Ii (native) is not one of them. The Fexofenadine 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

Collagen Type Ii (native) monograph Uses, safety profile, and every drug interaction in one place Fexofenadine drug information The full plain-English guide to this medication Fexofenadine supplement interactions Every supplement checked against Fexofenadine, 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 5 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Fexofenadine and Collagen Type Ii (native)?

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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.