Professor Wass' research interests include pituitary tumours, acromegaly, adrenal disease, angiogenesis in endocrinology, genetics of osteoporosis and thyroid disease. He is Chair of the Group on Weight and Health and Spokesperson on Obesity at the Royal College of Physicians.

He has published over 440 articles and edited numerous textbooks, including the Oxford Textbook of Endocrinology (3 editions), Clinical Endocrine Oncology (2 editions), Oxford Handbook of Endocrinology (4 editions). Between 2001-2003, he was President of the European Federation of Endocrine Societies and was Chairman of the Society for Endocrinology between 2006-2009. He is currently the President of the American Pituitary Society.

He has received numerous awards throughout his career, including becoming the first non-American to win the Outstanding Scholarly Physician Award from the American Endocrine Society in 2016. He was granted the American Pituitary Society Lifetime Achievement Award in 2017 and the European Society of Endocrinology's Geoffrey Harris Prize in 2021. In 2016, he also presented the acclaimed documentary 'The Fantastical World of Hormones' on BBC 4.

He is currently the endocrinology lead at the NHS Getting It Right First Time (GIRFT) initiative, a national programme designed to improve medical care within the NHS by reducing unwarranted variations, visiting and inspecting all 127 endocrine departments in the UK and completing a national report.