The tingling sensation that you may feel is a result of the beta-alanine and/or niacin and is referred to as paresthesia. This may sound a little unsettling, but it is completely harmless and shouldn’t worry you in the slightest. The feeling typically begins in your hands, arms, legs, or feet but can travel to other parts of the body as well. Shockingly enough, in plain words, it’s the same feeling as when your hand or foot falls asleep from being in the same position for too long. Some runners have actually grown to like the feeling of tingling, and because it usually subsides as your muscles begin to warm up, it really motivates athletes to get moving to wash away the strange feeling.