Carnosine is a naturally occurring dipeptide composed of beta-alanine and histidine, found in high concentrations in skeletal muscle and brain tissues. Its use to support the muscle system is primarily justified by scientific research. Carnosine acts as an intracellular buffer, helping to maintain pH balance in muscle cells during high-intensity exercise by neutralizing the accumulation of hydrogen ions, which can otherwise lead to fatigue and reduced performance. Several human studies show that increasing carnosine levels in muscle, typically through supplementation with beta-alanine (a carnosine precursor), can enhance exercise capacity, delay the onset of fatigue, and improve performance during high-intensity activities.

For example, a number of randomized controlled trials have demonstrated that beta-alanine supplementation increases muscle carnosine content and can improve outcomes in activities involving repeated bursts of high-intensity effort, such as sprinting or weightlifting. However, the direct supplementation of carnosine itself is less effective, as it is rapidly broken down in the digestive tract. Most benefits are thus seen with beta-alanine supplementation, which is scientifically validated as the more effective way to raise intramuscular carnosine.

While the evidence for carnosine’s role in muscle function is substantial, it is not universal for all types of exercise or populations, and the magnitude of benefit is generally moderate. Therefore, the evidence rating is 3 out of 5.