N-Acetyl-Carnosine (NAC), like its parent compound, carnosine, occurs naturally throughout the human body. Both compounds are found primarily in the heart, skeletal muscles and the brain. Carnosine was discovered in 1900 in Russia, and it is in Russia that most of the recent research on the N-Acetyl-Carnosine derivative has been carried out. Research with N-acetyl-carnosine, as with carnosine, demonstrates that it is effective not only in preventing cataracts but also in treating them. NAC has been shown to improve vision by reversing the development of the cataract, thus increasing the transmissivity of the lens to light.
The structural difference between NAC and carnosine is that one hydrogen atom in carnosine replaces an acetyl group (CH3CO-) and this substitution occurs at a nitrogen atom. An important chemical difference between carnosine and N-acetyl-carnosine is that carnosine is relatively insoluble in lipids (fats and fatty compounds), whereas N-Acetyl-Carnosine is relatively soluble in lipids (as well as in water).
This means that N-Acetyl-Carnosine may pass through the lipid membranes of the corneal and lens cells more easily than carnosine, and may thereby gain access more readily to the cells’ interior, which is primarily aqueous. There, the N-Acetyl-Carnosine is gradually broken down to carnosine which then exerts its beneficial effects.