Ben Greenfield, born on December 20, 1981, is an American fitness expert, biohacker, and internet personality widely recognized for his work in health, longevity, and fitness. He's known for his science-based approach to health and performance. Greenfield is the founder of Ben Greenfield Life, a personal blog with fitness tips, and co-founder of KION, a supplement company. He holds certifications in personal training, strength and conditioning, and sports nutrition.
Greenfield has received accolades such as the NSCA Trainer of the Year award in 2008 and has been listed among the Top 100 Most Influential People in Health and Fitness by Greatist. He is a top-ranked USAT triathlete and has completed 13 Ironman competitions in Hawaii. In June 2025, Greenfield was appointed as a strategic advisor to Gurner Group's Saint Haven and SAINT private health clubs, where he will develop anti-aging protocols. He is the author of multiple books, including New York Times bestsellers "Beyond Training" and "Boundless". Greenfield also hosts the "Boundless Life Podcast". He currently resides in Spokane, Washington, with his wife and twin boys.