Carnosine supplementation improves glucose control in adults with pre-diabetes and type 2 diabetes: a randomised controlled trial

Type 2 diabetes (T2DM) is a major cause of morbidity and mortality globally. Carnosine, a naturally occurring dipeptide, has anti-inflammatory, antioxidant, and anti-glycating effects, with preliminary evidence suggesting it may improve important chronic disease risk factors in adults with cardiometabolic conditions. In this randomized controlled trial, 43 adults (30%F) living with prediabetes or T2DM consumed carnosine (2 grams) or a matching placebo daily for 14 weeks to evaluate its effect on glucose metabolism assessed via 2 hr, 75g oral glucose tolerance test. Secondary outcomes included body composition analysis by dual energy x-ray absorptiometry (DEXA), calf muscle density by pQCT and anthropometry. Carnosine supplementation decreased blood glucose at 90 minutes (−1.31mmol/L; p=0.02) and 120 minutes (−1.60mmol/L, p=0.02) and total glucose area under the curve (−3.30mmol/L; p=0.04) following an oral glucose tolerance test. There were no additional changes in secondary outcomes. The carnosine group results remained significant before and after adjustment for age, sex, and change in weight (all>0.05), and in further sensitivity analyses accounting for missing data. There were no significant changes in insulin levels. Likely mechanisms may include changes to hepatic glucose output explaining the observed reduction in blood glucose without changes in insulin secretion following carnosine supplementation. This study provides preliminary support for larger trials evaluating carnosine as a potential treatment for prediabetes and the early stages of T2DM.