# Considerations for Carnosine Actions in Biology

## TL;DR

This paper discusses the various roles and effects of carnosine in biological systems, emphasizing its potential and uncertainties, especially during development.

## Contribution

The paper highlights the need to reconsider carnosine's applications due to its complex and variable biological effects.

## Key findings

- Carnosine affects cell survival, redox homeostasis, and signaling.
- Its effects vary based on factors like concentration, exposure time, and developmental stage.
- Carnosinemia, a disorder involving carnosine accumulation, is linked to neuropsychomotor dysfunction.

## Abstract

Carnosine is a histidinic dipeptide mainly identified for its pH buffering, antioxidant and metal chelating capacities. Several studies have explored the potential benefits of carnosine as a supplement for exercise, as well as an adjuvant treatment in several pathologies; however, roles and impacts of carnosine on most tissues, including the brain, are still under debate, especially in earlier stages of development. There is evidence that carnosine may impact a myriad of physiological parameters. It includes potential roles of carnosine as a modulator of cell survival, redox homeostasis, signaling and metabolism, among other functions. Many variables seem to impact the outcomes of carnosine actions (e.g., carnosine concentrations, length of exposure, target cell/tissue, biological sex, metabolic state, and developmental stage). Considering that the physiology and metabolism of histidine dipeptides change throughout life, impacts of carnosine during development should be carefully considered. This is particularly relevant in light of carnosinemia, an inherited disorder of carnosine catabolism characterized by the accumulation of carnosine and presenting neuropsychomotor dysfunction. Thus, rethinking the applications of carnosine is crucial for realization of the full potential of this promising molecule.