38TERA® is built on evidence-based formulas
that support health where it matters - in your gut.
38TERA® was founded by Dr. Will Bulsiewicz, a leading gastroenterologist and authority on the microbiome, with a clear mission: to set a new standard in gut health supplements.
At 38TERA®, we believe the right way to your health starts with your gut. Our formulations are built on the latest gut health science, using only rigorously researched ingredients that are safe, effective, and purposeful. Every product is manufactured in FDA- and GMP-accredited facilities and verified through independent third-party testing, so you can trust what you’re putting into your body.
We’re committed to full transparency—sharing what goes in, why it’s there, and leaving out what doesn’t belong. No harmful additives. No artificial fillers. Just clean, evidence-based nutrition to support your microbiome.
We’re not just supporting gut health—we’re setting a new standard for it.
Meet Dr. B
Dr. Will Bulsiewicz (or "Dr. B") is an award winning gastroenterologist, internationally recognized gut health expert, the New York Times-bestselling author of Fiber FueledandThe Fiber Fueled Cookbook, and the Founder of 38TERA. His research has been published in Nature Medicine, Gastroenterology and more. He has given more than forty presentations at scientific meetings, spoken to Congress and the USDA, and through social media, podcasts, his books and courses he has educated millions on the importance of gut health.
Dr. Will Bulsiewicz, MD, MSCI
Education, training, and awards
Education
Vanderbilt University
Bachelor of Science, Chemistry
Georgetown University
Doctor of Medicine
Northwestern University
Master of Science, Clinical Investigation
Training
Northwestern University (McGaw Medical Center)
Intern, Resident, & Chief Medical Resident
University of North Carolina Hospitals
Gastroenterology Fellow, GI Epidemiology Fellow & Chief GI Fellow
UNC-Gillings School of Global Public Health
Fellow in Translational and Clinical Research Curriculum
Awards
Rambach Award
Northwestern “Intern of the Year”
Alpha Omega Alpha Medical Honor Society
National Institutes of Health LRP Grant Recipient
AGA/ASGE President Plenary
Digestive Disease Week 2013
UNC Award for Excellence in Clinical Gastroenterology
During 20 years of studying medicine, Dr. B developed a unique approach to healing patients by addressing the root cause of their issues: gut health. By focusing on restoring the microbiome through targeted nutrition, lifestyle changes, and supplements, he achieved remarkable results. Inspired to share his methods with a wider audience, he authored two New York Times bestselling books, built a large online community, and created popular digital courses on gut health.
However, he encountered a significant problem: the available gut health supplements didn't meet his high standards. The market was flooded with outdated products lacking scientific backing, transparency, and third-party testing—more hype than help. Frustrated by this gap, he decided to do something radical and build the brand that he always wished existed.
During 20 years of studying medicine, Dr. B developed a unique approach to healing patients by addressing the root cause of their issues: gut health. By focusing on restoring the microbiome through targeted nutrition, lifestyle changes, and supplements, he achieved remarkable results. Inspired to share his methods with a wider audience, he authored two New York Times bestselling books, built a large online community, and created popular digital courses on gut health.
However, he encountered a significant problem: the available gut health supplements didn't meet his high standards. The market was flooded with outdated products lacking scientific backing, transparency, and third-party testing—more hype than help. Frustrated by this gap, he decided to do something radical and build the brand that he always wished existed.
The right way to your health starts with evidence, integrity, and impact.
At 38TERA®, we bring clinical precision, transparency, and innovation to every step — from formulation to your daily habit.
Verified Quality
Clinically studied ingredients. FDA- and GMP-certified production. Third-party tested for purity and safety.
Science-Led Formulation
Guided by data, not trends. Every dose grounded in clinical research and peer review.
Continuous Innovation
Relentless refinement through ongoing testing, research, and new certifications.
Education & Connection
Empowering you with credible science and a community built on real gut health.
