Background: Adipokines play an important role in the pathophysiology of type 2 diabetes and cardiovascular diseases. We have previously shown that carnosine supplementation improved glucose metabolism in non-diabetic individuals. 
Aim: To investigate whether the improvement in glucose metabolism was modulated by adipokines. 
Methods: Twenty-two overweight and obese otherwise healthy adults were randomly assigned to receive either 2g of carnosine (n=13) or identical placebo (n=9) for 12 weeks. Serum adiponectin, adipsin, leptin and resistin were analysed using a bead-based multiplex assay (LEGENDPlex™, BioLegend). Urinary carnosine, carnosine propanal and propanol were measured by mass spectrometry. 
Results: Carnosine supplementation decreased resistin levels compared to placebo (mean change from baseline: -35 ± 83 carnosine vs 35 ± 55 ng/ml placebo, p=0.04). There was also a trend for reduction in leptin levels after carnosine supplementation (-76 ± 165 carnosine vs 35 ± 55 ng/ml placebo, p=0.06). Adiponectin and adipsin levels were not different between the groups (both p>0.1). Change in leptin and resistin were inversely related to change in levels of urinary carnosine (r =-0.72, p = 0.0002; r=- 0.67, p=0.0009, respectively), carnosine propanal (r=- 0.56, p=0.005; r=- 0.63, p=0.001, respectively) and propanol (r=-0.61, p=0.002; r =- 0.61, p=0.002, respectively) and remained significant after adjustment for age, sex and body mass index (all p<0.001). Leptin and resistin levels did not correlate with markers of glucose metabolism (all p>0.1). 
Conclusion: These findings suggest that carnosine supplementation might reduce serum adipokines associated with obesity and insulin resistance. Future trials with larger sample sizes are needed.

Effect of carnosine supplementation on serum adipokines in overweight and obese adults: a randomised controlled trial