Will Bulsiewicz MD

Will Bulsiewicz, MD, MSCI—known as “Dr. B”—is an award-winning gastroenterologist, gut health expert, and New York Times bestselling author of Fiber Fueled, The Fiber Fueled Cookbook, and Plant Powered Plus. He has authored more than twenty-five scientific papers and delivered keynotes to organizations including Congress, the USDA, and major medical conferences. As Co-Founder and Co-CEO of 38TERA, Dr. B collaborates with nutrition scientist Simon Hill to develop clinically informed, microbiome-supportive supplements grounded in quality, efficacy, and transparency. His work bridges rigorous science with real-world application, helping people use the power of the gut microbiome to restore balance, reduce inflammation, and achieve lasting wellness. He lives in Charleston, South Carolina with his wife and four children.