Adiponectin is a hormone secreted exclusively by adipose tissue. Counterintuitively, lean people produce more of it than obese.
Mechanism — Binds AdipoR1/R2 to enhance insulin sensitivity, increase fatty acid oxidation, reduce gluconeogenesis, and suppress vascular inflammation. Levels drop in visceral obesity and metabolic syndrome.
Lab range — Reference is broad (2-30 ug/mL). Higher within the range correlates with better cardiometabolic outcomes. Increased by weight loss, exercise, and omega-3s.
Caveats — Genetic component is significant. Don't chase the number — it tracks lifestyle improvements rather than driving them.