Does lactic acid come from milk?

Why is lactic acid associated with milk?

The connection is genuine: the chemist Carl Wilhelm Scheele first extracted lactic acid from milk in 1780. Lactic acid is also present in yogurt. That history explains the association with dairy, but it does not identify the raw material used to manufacture a particular serum or cream.3

Does lactic acid mean a product is not vegan?

The ingredient name alone is not enough to decide. Fermentation is a production method, not confirmation of which raw materials a manufacturer used. Neither the milk connection nor the possibility of fermentation settles whether a particular product meets your requirements. Ask the brand where its lactic acid comes from if you want to avoid animal ingredients, because an ingredient list is not a factory tour. Make the question specific to the product you plan to buy rather than asking about lactic acid in general.2

What does lactic acid do in skincare?

Lactic acid is an alpha hydroxy acid, or AHA: an acid used to exfoliate the skin's surface. It helps remove accumulated dead skin cells, which can leave skin feeling smoother. Lactic acid also has moisture attracting properties and is part of the skin's natural moisturizing factor, the substances that help keep skin hydrated. Its skincare role is therefore not limited to its association with milk. These are general ingredient properties, not a reason to expect every lactic acid product to give the same result.13

Can you use milk instead?

Milk baths can offer some exfoliation from lactic acid and some moisturizing from milk fats, but research on their benefits is limited. Milk baths have a long beauty history, which is not the same thing as a long list of clinical results. Treat a milk bath as a separate practice rather than a replacement with a known skincare acid strength.1

If you try one, add one or two cups of milk to warm bathwater, stay in for no more than 15 to 20 minutes, and rinse afterward to remove residue. Skin irritation is possible. Avoid cow's milk baths if you have a severe cow's milk allergy, and avoid nut based milk alternatives if you have a nut allergy.1