I heard this idea many times, here for example.
Brewer’s yeast contains many vitamins, minerals and proteins that are indispensable for your hair. The lack of these nutrients, instead, may cause weak, dull and brittle hair fibre, prone to breakage. The B-complex vitamins present in this yeast contain folic acid, riboflavin, niacin, thiamin and piroxin that are fundamental to hair structure, as well as to its growth, while minerals, such as calcium, copper, chromium and iron, help maintain hair color and prevent loss. Proteins found in the brewer’s yeast are beneficial for damaged and weak hair and necessary for proper hair nutrition.
Is there anything proven regarding brewer’s yeast’s effect on hair (growth, volume…)?