Carnosine is a dipeptide composed of beta-alanine and histidine, found in high concentrations in muscle and nervous tissue. Its proposed benefit in diabetic retinopathy derives mainly from its antioxidant, antiglycation, and anti-inflammatory properties. Diabetic retinopathy is characterized by oxidative stress, inflammation, and the formation of advanced glycation end-products (AGEs), all of which contribute to retinal damage in diabetes. Several in vitro and animal studies have demonstrated that carnosine can inhibit the formation of AGEs and reduce oxidative stress markers, suggesting a potential protective effect on retinal cells exposed to hyperglycemic conditions.

However, clinical evidence in humans remains limited. Few small-scale studies and clinical trials have explored the direct effect of carnosine supplementation—either orally or as eye drops—on diabetic retinopathy progression. Most available data are preclinical, with some studies reporting that carnosine administration can decrease retinal vascular leakage and apoptosis in diabetic animal models. Reviews and meta-analyses of nutraceutical interventions in diabetic retinopathy may mention carnosine, but generally emphasize the need for larger, well-designed clinical trials.

In summary, while there is a growing body of preclinical evidence supporting carnosine’s potential utility in diabetic retinopathy, robust clinical validation is lacking. Its use is therefore based on scientific rationale and preliminary research, but evidence supporting efficacy in humans is currently weak to moderate (rated 2/5).