Beta-alanine raises muscle carnosine, which helps buffer acid during very hard efforts. It is one of the few supplements with fairly consistent support, but only for a specific window of effort.
Key points:
Benefits are most likely in high-intensity efforts lasting roughly 30 seconds to about 10 minutes
It works by loading, not acutely: commonly around 3-6 g per day, split into smaller doses, for at least 4 weeks
Effects are modest; useful at the margins, not a game changer
Long steady endurance events are less likely to benefit