Is Rennet Vegetarian?

Depends on Source

Vegan: Depends on Source How we decide

Some routes to it require the animal to die and some do not, and the label rarely says which was used.

The two diets, side by side

A vegetarian diet excludes animals that were killed. A vegan diet excludes animal products entirely, whether the animal survived or not. Rennet can fall either side of that line depending on how it was made.

Rennet depends on the cheese. Traditional rennet is taken from the stomach lining of slaughtered calves, lambs, or kid goats, while most cheese made today sets with fermentation-produced chymosin or a microbial enzyme, both animal-free. Parmigiano-Reggiano, Grana Padano, and traditional Gruyère are bound by PDO rules to use the calf version.

Relevant to: Mammal

What it is

Comes from: Traditional animal rennet is extracted from the stomach lining of slaughtered calves, lambs, or kid goats [not vegan]. Alternatives include: microbial rennet from fungi/bacteria [vegan], vegetable rennet from plants like nettles or fig sap [vegan], and fermentation-produced chymosin (FPC) [vegan, used in most commercial cheese today].
Which animal: calf, lamb, or kid goat
Requires slaughter: Yes
Where you meet it: Cheese (all types). Most commercially produced cheese today uses FPC or microbial rennet. Traditional cheeses (Parmigiano-Reggiano, Grana Padano, traditional Gruyère) require animal rennet by their protected designation of origin (PDO) rules.
What replaces it: Microbial rennet, vegetable rennet, or fermentation-produced chymosin (FPC).

Editorial notes

Most modern commercial cheese uses FPC rennet, which is produced by inserting calf chymosin genes into fungi or bacteria. The resulting enzyme is biochemically identical but is not animal-sourced — considered vegan by most standards.

Frequently asked questions

Is Rennet vegetarian?

Depends on Source. Some routes to it require the animal to die and some do not, and the label rarely says which was used.

Is Rennet vegan?

Depends on Source. Rennet depends on the cheese. Traditional rennet is taken from the stomach lining of slaughtered calves, lambs, or kid goats, while most cheese made today sets with fermentation-produced chymosin or a microbial enzyme, both animal-free. Parmigiano-Reggiano, Grana Padano, and traditional Gruyère are bound by PDO rules to use the calf version.

Is rennet vegan?

It depends on the source. Traditional animal rennet, taken from the stomach lining of slaughtered calves, lambs, or kid goats, is not vegan. Microbial rennet, vegetable rennet, and fermentation-produced chymosin (FPC) are non-animal and are generally considered vegan.

Is rennet vegetarian?

Animal rennet is not vegetarian because it requires slaughtering young animals. Cheeses labeled vegetarian typically use microbial rennet or fermentation-produced chymosin instead. If a cheese does not specify, its coagulant source may be animal-derived.

What can I use instead of animal rennet?

The main non-animal alternatives are microbial rennet, fermentation-produced chymosin (FPC), and vegetable rennet from plants like thistle or nettle. FPC is the most common in modern industrial cheese and behaves almost identically to calf chymosin. Microbial rennet is widely available for home and commercial cheesemaking.