Sir Stephen O'Rahilly FMedSci FRS

Stephen O’Rahilly is an endocrinologist who has transformed our understanding of the control of human energy balance and metabolism and how these can be disturbed to cause severe obesity and/or subtypes of diabetes. Stephen showed that mutations in single genes can cause a catastrophic loss of control of appetite and feeding behaviour, leading to severe obesity. Some of these inherited disorders can now be treated very effectively.

Stephen studies patients with extreme and inherited metabolic conditions such as severe obesity and insulin resistance. His work first established that some very obese children have a mutation in the gene for leptin — an appetite-controlling hormone. His work has led to a better understanding of how the brain senses its state of nutrition and controls not only appetite but growth, the rate of pubertal development and the accrual of muscle mass. His work  revealed the genetic basis for more than 20 human disorders and he works with industry to develop targeted treatments.

From modest beginnings, Stephen has built up and leads one of the world’s largest institutes for metabolic research at the University of Cambridge. His findings have been recognised internationally with many awards and prizes, and in 2013 he was knighted for services to medical research.

Subject groups

  • Health and human sciences

    Clinical endocrinology


  • Croonian Medal and Lecture

    For their seminal discoveries regarding the control of human body weight, resulting in novel diagnostics and therapies, which improve human health (with Professor Sadaf Farooqi FMedSci FRS).

Sir Stephen O'Rahilly FMedSci FRS
Elected 2003