Beta-alanine is a nonproteinogenic amino acid (i.e., it is not incorporated into proteins during translation). It is synthesized in the liver and can be ingested in the diet through animal-based foods like beef and chicken. Once ingested, beta-alanine combines with histidine within skeletal muscle and other organs to form carnosine. Beta-alanine is the limiting factor in muscle carnosine synthesis.
Beta-alanine has been shown to enhance muscular endurance during high-intensity exercise lasting 1–10 minutes. Examples of exercise that may be enhanced by beta-alanine supplementation include 400–1500 meter running and 100–400 meter swimming.
Carnosine also appears to exert antiaging effects, mainly by suppressing errors in protein metabolism, as the accumulation of altered proteins is strongly associated with the aging process. These antiaging effects may derive from its role as an antioxidant, a chelator of toxic metal ions, and an antiglycation agent.
Large doses of beta-alanine may cause a tingling feeling called paresthesia. It is a harmless side effect, but some people find the sensation uncomfortable.
Studies have investigated a range of 3.2–6.4 grams per day of beta-alanine. To avoid paraesthesia, a dose of 0.8-1.6 grams of beta-alanine every 3-4 hours is recommended. There are also sustained-release formulations available that permit the use of greater doses without the risk of paresthesia. Although beta-alanine is commonly included in preworkout stacks, the timing of ingestion does not influence its effectiveness.
When beta-alanine is ingested, it turns into the molecule carnosine, which acts as an acid buffer in the body. Carnosine is stored in cells and released in response to drops in pH. During intense exercise, carnosine binds to hydrogen ions (H+) to attenuate the decline in intracellular pH, allowing for a longer duration of exercise at higher intensity.