Carnosine is a multifunctional dipeptide made up of a chemical combination of the amino acids beta-alanine and l-histidine. Long-lived cells such as nerve cells and muscle cells contain high levels of carnosine. Muscle levels of carnosine correlate with the maximum life spans of animal species. Carnosine levels decline with age. Carnosine has the remarkable ability to rejuvenate cells approaching senescence (the end of the life cycle of dividing cells), restoring normal appearance and extending cellular life span. As an antioxidant, carnosine potently quenches that most destructive of free radicals, the hydroxyl radical, as well as superoxide, singlet oxygen and the peroxyl radical. Surprisingly, carnosine was the only antioxidant to significantly protect chromosomes from oxidative damage due to 90% oxygen exposure.

Carnosine's ability to rejuvenate connective tissue cells may explain its beneficial effects on wound healing. In addition, skin aging is bound up with protein modification. Damaged proteins accumulate and cross-link in the skin, causing wrinkles and loss of elasticity. In the lens of the eye, protein cross-linking is part of cataract formation.

Now that many are cutting down on meat -the main dietary source of carnosine –supplementation, when indicated, becomes more important. Carnosine is safe, with no toxicity even at dosages above 500mg/Kg of body weight in animal studies. The enzyme carnosinase must be saturated with more carnosine than it is able to neutralize in order to make free carnosine available to the rest of the body.

There are thought to be many mechanisms responsible for aging. Carnosine's life extension potential places it on a par with CoQ10 as a cornerstone of longevity nutrition.