Carnosine

Carnosine is a dipeptide of beta-alanine and L-histidine, concentrated in skeletal muscle and nervous tissue. It operates through four mechanisms: intracellular pH buffering during high-intensity exercise, reactive carbonyl scavenging (trapping aldehydes before protein crosslinking occurs), chelation of redox-active ions such as copper(II) and zinc(II), and quenching of reactive oxygen species. In geroscience, its anti-glycation activity is particularly relevant: carnosine inhibits the formation of advanced glycation end products (AGEs), protein-sugar adducts that accumulate in aged tissue and promote vascular and neurological damage. Intramuscular carnosine declines by approximately 47–63% between early adulthood and the seventh decade — with the steeper losses in fast-twitch type II fibers. A double-blind, placebo-controlled RCT (Houjeghani 2018; n = 54 adults with type 2 diabetes) found that 12 weeks of oral L-carnosine (1 g/day) significantly reduced serum AGEs and TNF-α versus placebo. Long-duration trials in healthy older adults remain absent; most human data derive from short trials in metabolically compromised populations, and the degree to which oral supplementation raises tissue carnosine — given rapid hydrolysis by serum carnosinase — is an active research question.