The hormone that promotes bone growth is called what?

• A. Insulin
• B. Melatonin
• C. Growth hormone
• D. Calcitonin

Answer: (C)

Growth hormone is the hormone that promotes bone growth. It’s produced by the anterior pituitary and drives the growth of long bones mainly during childhood and adolescence by stimulating the growth plates. It acts directly on bones and, more importantly, stimulates the liver and other tissues to release IGF-1, which promotes chondrocyte proliferation and bone formation at the growth plates. This combination of direct and IGF-1–mediated effects results in added length and overall bone growth.

Understanding the others helps put this in context: insulin helps with overall growth and metabolism but isn’t the primary driver of bone length; melatonin regulates sleep-wake cycles and has little to do with promoting bone growth; calcitonin lowers blood calcium and inhibits bone resorption rather than driving new bone length.