Is Pepsin Vegan? The Animal Enzyme in Supplements

You probably only notice pepsin when you read the back of a digestive supplement. It sounds like a chemical, but it has an animal source, and that source is why it is not vegetarian or vegan.

Key Takeaways

• Pepsin is a digestive enzyme that breaks down protein.
• It is traditionally extracted from pig stomachs, so it is not vegetarian or vegan.
• It hides in digestive supplements and is used in some cheese-making.
• Plant alternatives include papain (papaya) and bromelain (pineapple).

TL;DR: Pepsin is not vegetarian or vegan. It is a digestive enzyme extracted from pig stomachs, found in digestive supplements and some cheeses.

What pepsin is

Pepsin is an enzyme that breaks down protein. Animals produce it in the stomach to digest food, and the commercial version is extracted from the stomach lining of pigs, where it is naturally abundant. That animal origin is the whole reason it is off-limits for vegetarians and vegans.

Where it hides

Pepsin is less visible than ingredients like gelatin, but it shows up in a few specific places:

• Digestive supplements, where it is often paired with other enzymes
• Some cheese-making, as a coagulant alongside or instead of rennet
• A few processed foods as a processing aid

On a supplement label it is usually just “pepsin,” with no mention of the source.

The plant alternatives

If you want a digestive enzyme without the animal source, the plant-based options do the same job:

• Papain, from papaya
• Bromelain, from pineapple
• Fungal proteases, from fermentation

Digestive supplements often list these as vegan alternatives to pepsin, and many labels now state “plant enzymes” or “vegan” to make the distinction clear.

How to check

1. Look for “pepsin” on supplement labels and assume it is animal-derived unless stated otherwise.
2. Choose products labeled “vegan” or “plant enzymes.”
3. For cheese, remember that pepsin and rennet are separate but often both animal-derived.
4. Scan the product. A scanner app flags pepsin and other animal-derived enzymes against your diet.

Pepsin is one of several animal-derived enzymes and additives. See our E-numbers cheat sheet for the rest, including rennet and l-cysteine.

The bottom line

Pepsin is an animal enzyme, usually from pigs, and it is not vegetarian or vegan. It hides mostly in digestive supplements. The plant alternatives are papain and bromelain, so the fix is a “vegan” or “plant enzymes” label.

Check before you eat. The Verify Veg app scans a barcode or reads an ingredient list from a photo and flags ingredients against your diet (vegan, vegetarian, halal, kosher, Jain and more). Download on the App Store - Android is coming soon.

Written by Samir Narain, founder of Verify Veg. Verify Veg helps people check packaged food against their diet by scanning barcodes and reading ingredient lists from photos.

Note: Verify Veg provides ingredient-based compatibility checks, not certification. Ingredient sources can vary by manufacturer, so always confirm with the brand or vendor.