Irisin
Irisin is a hormone released by muscles during exercise that helps convert energy-storing white fat into energy-burning beige fat.
Plain English
Patient-Friendly Explanation
Irisin is a hormone your muscles release when you exercise. It travels through the bloodstream to fat tissue, where it encourages 'white' fat cells — which store energy — to take on features of 'beige' fat, which burns energy as heat. This is one of the reasons regular exercise does more than just burn calories; it can actually change how your body handles fat.
Medical
Clinical Definition
Irisin is a myokine cleaved from the transmembrane protein FNDC5 and secreted by skeletal muscle in response to exercise, particularly endurance training. It acts on white adipose tissue to induce 'browning' — upregulating uncoupling protein 1 (UCP1) and increasing thermogenesis — and has been shown to improve glucose homeostasis. Circulating irisin levels are lower in obesity and type 2 diabetes and rise after exercise training, though assay reliability has been debated. It represents a molecular link between physical activity and metabolic health.
Key Insight
Why It Matters
Exercise changes your body at a hormonal level, not just a calorie level — which is why activity is a core pillar of the weight management programme at Accord Medical.
Sources
Reviewed against standard medical references.
Medically reviewed by
Family Physician & Registered Acupuncturist, Accord Medical Clinic. MBBS (NUS), Graduate Diploma in Family Medicine (NUS), Graduate Diploma in Acupuncture (Singapore College of TCM).
Last reviewed: August 2026
This page is general health education, not medical advice. Whether any treatment is appropriate for you is a decision made in consultation after assessment.
