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Allergen & sensitivity guide

Shellfish in skincare: the hidden names to check for

If you react to shellfish, the word itself is rarely what's on the label. Here are the names it hides behind — and what it can cross-react with.

The names Shellfish appears under

On an ingredients (INCI) list, watch for:

chitinchitosanglucosaminecrustaceanshrimpcrablobsterkrill

Seeing any of these means the product may contain shellfish, even if the front of the pack says nothing about it.

What it can cross-react with

Most shellfish allergy is a reaction to tropomyosin, a muscle protein shared across crustaceans and mollusks. Snails are mollusks too, so snail mucin (snail secretion filtrate) can carry the same protein and cross-react — if you're allergic to shellfish, patch-test snail-mucin products first, or skip them.

Snail mucin

Could Shellfish be why your skin keeps reacting?

If a product "breaks you out" for no obvious reason, a hidden ingredient is a common culprit — and because shellfish rarely appears under its plain name, it's easy to keep buying it by accident across totally different products. Reactions can look like redness, stinging, small bumps, itchiness, or a rash where you applied it. The pattern to watch for: it happens with several products that seem unrelated, but share one of the names above.

What to do if you think you're reacting to Shellfish

How Vaiya checks every product for Shellfish

When you tell Vaiya you react to shellfish, our allergen engine screens each product's full ingredient list for all of the hidden names above — not just the obvious one — and never recommends a product we can't verify is clear. It's the same check, free, for everyone, and it's the fastest way to find products that fit you. Check your shelf against shellfish →

Why you can trust this: Vaiya's recommendations are commission-blind — what we suggest and what we flag as unsafe is decided by an engine that never sees affiliate data, and that separation is enforced by an automated test in our build. We can't be paid to fake a safe.
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