Completed his medical studies at the University of Montreal, after obtaining a master's degree in sociology at the University Laval.
He worked for seven years in peripheral region, holding several positions, including chief of the emergency department and responsible for continuing medical education.
Upon his return to the metropolitan area, he joined the Centre Cardio Vasculaire de Laval where he honed his expertise in cardiovascular prevention and as a consultant to physicians of Laval and of the Laurentians.
In 2004, he completed training on acquired hypogonadism (andropause) for which heightened interest is confirmed since. He is also a member of the Advisory Committee of the Institute of Medical hypogonadism
More recently, in 2010-2011, Dr. Gagnon has completed training in sexual medicine.
He participates in numerous clinical studies on vascular diseases, diabetes, hypertension and lipidic disorders.
Member of the following associations: Canadian Diabetes Association, Diabetes Quebec, Canadian Hypertension Society, Quebec Hypertension Society, Society of Quebec Lipid Metabolism and Nutrition, Society of Vascular Science of Quebec, International Society of Atherosclerosis, International Society for the Study of Aging Male, and sexual Medicine Association of Quebec.