Leptin

Leptin is a hormone produced by fat cells that helps regulate appetite and energy balance by signaling the brain when you have enough stored fat. This test measures the level of leptin in your blood.

Category: Diabetes & Glycemic

Also known as: leptin, serum leptin, ob protein

Reference range: 2–5.6 ng/mL (Source: ABIM)

Standard unit: ng/mL

High values may indicate

High leptin levels may indicate leptin resistance (common in obesity), where the brain does not respond properly to leptin signals, leading to continued overeating and weight gain.

Low values may indicate

Low leptin levels may indicate lipodystrophy (loss of body fat), severe caloric restriction, or genetic leptin deficiency, which can cause extreme hunger and early-onset obesity.

Source: MedlinePlus, U.S. National Library of Medicine

Track your Leptin over time with BloodId