Marvin is currently the director of Integrative Gastroenterology at the Susan Samueli Integrative Health Institute at UC Irvine. He is also currently a voluntary assistant clinical professor at UCSD in the Department of Family Medicine and Public Health. Prior to this, he was a clinical assistant professor at UCLA and an assistant professor of medicine at Johns Hopkins University. Marvin is a member of the American Academy of Anti-Aging Medicine, American College of Lifestyle Medicine, and many other societies. He is also actively involved in the American Gastroenterological Association. Marvin co-edited the textbook Integrative Gastroenterology, 2nd edition (a Weil Series text) and has written several book chapters and articles.

He is dedicated to guiding his clients toward optimal wellness every step of the way, using the most cutting-edge technologies to design highly personalized precision-based protocols and help them stay on top of their health, rather than underneath disease. Towards this end, he founded Precisione Clinic to bring the best in preventive medicine to his clients.