Carnosine

In muscle, carnosine helps buffer the acid that builds up during hard exercise. In laboratory studies it also binds metal ions, acts as an antioxidant, and limits the formation of advanced glycation and lipoxidation end products, harmful compounds formed when sugars and oxidized fats react with proteins¹. An enzyme in human blood, serum carnosinase, actively splits carnosine back into histidine and beta-alanine¹, so carnosine taken by mouth may not reach tissues intact. Beta-alanine, rather than carnosine itself, is the building block that mainly controls how much carnosine the body makes¹.

In donated human skin samples kept alive in the lab, topically applied carnosine reduced reactive oxygen species and glycation products after simulated sunlight⁶.

Human trials are small and mostly short. In a 14-week randomized trial of 43 adults with prediabetes or type 2 diabetes, carnosine lowered blood sugar at later time points of a glucose tolerance test compared with placebo, without changing insulin levels².

A 2025 meta-analysis of eight trials (377 participants) reported modest reductions in fasting glucose and HbA1c, but it pooled carnosine with its precursor beta-alanine, so the effect of carnosine alone is unclear³. In a 299-person randomized trial, carnosine did not improve most measures of physical performance; small gains appeared only in certain age and sex subgroups⁴. The skin findings come from donated skin tissue in the lab, not from people using carnosine products⁶.

A broad review describes promising animal and early clinical findings in diabetes, eye disease and neurological conditions, but large human trials are lacking¹.

Carnosine is not an FDA-approved drug; in the US it is marketed as a dietary supplement.

In the largest trial (299 adults over about three months), serious adverse events were few and equal in number between carnosine and placebo (three each); tingling sensations were reported more often with carnosine (11 people vs 3), and nausea was similar⁵. Other trials were too small and short to detect uncommon or long-term effects.

1. Boldyrev et al., Physiol Rev 2013PubMed
2. Hariharan et al., Nutr Metab Cardiovasc Dis 2024PubMed
3. Li et al., BMC Endocr Disord 2025PubMed
4. O'Toole et al., J Int Soc Sports Nutr 2026PubMed
5. ClinicalTrials.gov: NCT03314987 (NEAT, results)ClinicalTrials.gov
6. Girardi et al., Photochem Photobiol 2024PubMed