Carnosine is a naturally occurring molecule in the body, with the highest concentrations in the muscles and the heart. The nervous system, including the brain, also produces its own carnosine.

But as we age, or as a result of chronic illness, that production may be impaired. In addition, an enzyme in the blood called carnosinase breaks down carnosine, lowering the level.

Carnosine is composed of two amino acids: alanine and histidine. It is completely natural and safe as a supplement. Some have recommended frequent dosing of L-carnosine to keep blood levels high.

N-acetyl-L-carnosine, a natural derivative of L-carnosine, is not destroyed by carnosinase. It is also available as a supplement, but it’s quite expensive compared to carnosine.

One of the functions of carnosine is lowering lactate and keeping the body’s pH within a proper physiological range. This increases muscle function, including greater endurance and muscle-building during exercise. It also prevents and can even reverse muscle loss associated with aging. In general, it is considered an anti-aging compound.

The brain generates the carnosine that is essential for brain cell function. Within the brain and nervous system, carnosine and its constituent amino acids act as neurotransmitters, enhance energy production, regulate brain cell pH, and control immune function.

In addition, carnosine inhibits destructive excitotoxicity (the main cause of Alzheimer’s and Parkinson’s diseases). Both astrocytes and microglia — cells that play major roles in brain repair — take up carnosine as a protective molecule.

One of the most important properties of carnosine is its ability to increase glutamate transporter 1 (GLT-1), which moves glutamate from outside the cell, where it is very destructive, to the inside, where it is safe.

We now suspect that several neurological diseases are caused by a defect in molecules, such as GLT-1, that protect brain cells. Age-related macular degeneration of the retina — which is a neural structure — is also related to carnosine deficiency.