Because beta-alanine can only be obtained through animal products, the only source of beta-alanine for vegetarians/vegans is endogenous production. People who follow a vegetarian diet were found to have a lower carnosine content in their skeletal muscle in an observational study.[1] Interestingly, one study observed no differences in baseline brain carnosine/homocarnosine levels between omnivores and vegetarians.[2]
Switching from an omnivorous diet to a vegetarian diet for 6 months does not appear to negatively affect carnosine stores in muscle — though adding beta-alanine to a vegetarian diet does increase muscle carnosine stores compared to a vegetarian diet only.[3]
Vegetarians and vegans should follow the same dosing protocols as omnivores: 3.2–6.4 grams per day, divided into 2–4 equal doses, for a minimum of 2–4 weeks.