United States
Dr. Will Bulsiewicz — widely known as Dr. B — is a triple board-certified gastroenterologist and lifestyle medicine physician based in the United States with over two decades of clinical experience.
Total Followers +2.1%
795K
Across YouTube, Instagram
Primary Platform
YouTube
126K followers · 16% of audience
Engagement
4.7%
vs. 1.5% category median
Sponsorship Tier
Mid
Est. $10K–$23K / IG post
Dr. Bulsiewicz's third book, Plant Powered Plus, was published in January 2026 and became a New York Times bestseller, adding to his prior hits Fiber Fueled and The Fiber Fueled Cookbook.
Appearing on PCRM's The Exam Room, Dr. Bulsiewicz discussed his new book's themes around gut health, chronic inflammation, and his own personal health journey including burnout and metabolic illness.
Bulsiewicz launched 38TERA, a microbiome supplement company, with Simon Hill as co-CEO. Its flagship product DMN (Daily Microbiome Nutrition) is a Low FODMAP-certified prebiotic blend derived from seven plants.
| Window | YouTube | Combined | ||
|---|---|---|---|---|
| Last 7 days | +3K +2.4% | +134 +0.0% | +0 +0.0% | +3K |
| Last 30 days | +16K +12.5% | +602 +0.1% | +0 +0.0% | +16K |
| Last 90 days | +69K +55.0% | +4K +0.6% | +0 +0.0% | +73K |
| Last 365 days | +69K +55.0% | +4K +0.6% | +0 +0.0% | +73K |
Daily follower snapshots from CreatorDB's longitudinal index.
| Brand | Type | Platform | Date | Performance vs. baseline |
|---|---|---|---|---|
| 38TERA Supplements / Gut Health | Founder / owned brand | 2022–Long-term | — | |
| ZOE Nutrition Science / Health Tech | Long-term partnership | YouTube | 2022–Long-term | — |
Dr. Will Bulsiewicz — widely known as Dr. B — is a triple board-certified gastroenterologist and lifestyle medicine physician based in the United States with over two decades of clinical experience. He built his public profile through a series of New York Times bestselling books, beginning with Fiber Fueled, which made the case for plant-rich diets as the primary lever for microbiome health and reached a general wellness audience well beyond traditional gastroenterology readership. His follow-up work, Plant Powered Plus, extended that platform further. He also founded 38TERA, a supplement line that functions as both a direct-to-consumer revenue channel and a clear signal of his evolution from practicing clinician to practitioner-turned-product entrepreneur.
Across YouTube and Instagram, Dr. B translates dense microbiome and nutrition research into accessible, evidence-backed content — listicle-style guides on anti-inflammatory foods, practical GLP-1 guidance for patients, and collaborative episodes with fellow clinicians. His audience skews heavily female and notably younger than typical medical-content demographics, with the 18–34 bracket forming the core of his following. That combination — clinical credibility, a proprietary supplement brand, and a health-conscious millennial and Gen Z audience with strong English-speaking reach across North America and the UK — positions him well for partnerships with functional food, diagnostics, and precision nutrition brands seeking physician-led validation.
Theguthealthmd reaches an audience concentrated in United States primarily through YouTube, and is best activated via long-form YouTube integrations, Instagram Reels and Stories. Their sponsorship history skews toward Supplements / Gut Health, Nutrition Science / Health Tech, a clear signal of fit for brands in those categories. Demonstrated partners include 38TERA and ZOE. Engagement on YouTube runs around 4.7%, which points to an audience better suited to category-relevant, mid-funnel campaigns than to pure-reach buys. The channel's mix of long-form YouTube integrations and Instagram Reels and Stories lets a sponsor choose between short awareness placements and longer, more detailed integrations. Because the audience follows health content rather than arriving through untargeted reach, sponsorships that match the channel's subject matter tend to convert more efficiently than broad placements. A consistent, on-topic posting focus gives sponsors a predictable, brand-safe environment, lowering placement risk compared with broad, general-interest channels. Campaigns here are best measured on qualified engagement and consideration within the niche rather than on raw impression volume. For United States-focused brands in Supplements / Gut Health and related categories, Theguthealthmd offers a defined, creative-fit audience rather than broad, low-intent impressions.
Benchmark estimates for a creator at Theguthealthmd's tier (Mid, 795K combined followers, United States). Pulled from CreatorDB's category benchmarks.
The CreatorDB Agency runs end-to-end influencer campaigns globally — shortlisting, outreach, contracting, and performance reporting. Talk to our team about building a campaign around creators in this niche.
The Gut Health MD is Dr. Will Bulsiewicz, a triple board-certified gastroenterologist who goes by 'Dr. B.' He has over two decades of clinical experience and focuses on translating microbiome science and nutrition research into practical, accessible advice for everyday people.
Yes, Fiber Fueled is one of Dr. Bulsiewicz's books and became a New York Times bestseller. He has since authored two additional NYT bestsellers, including Plant Powered Plus, making him a three-time NYT bestselling author in the gut health and plant-based nutrition space.
38TERA is a supplement brand founded by Dr. Will Bulsiewicz himself. He describes it as his own standard for what a supplement should be, built on the science-backed rigor he applies to his clinical and research work rather than typical commercial supplement formulations.
Dr. B has published content specifically covering what patients taking GLP-1 medications need to know from a gut health standpoint, including nutritional considerations and potential digestive impacts. His perspective is rooted in his clinical practice as a gastroenterologist who sees these patients directly.
Yes, Dr. Bulsiewicz hosts a podcast where he interviews fellow medical doctors and gut health experts on topics ranging from the microbiome to inflammation and plant-based nutrition. It extends the same evidence-based approach he takes on his YouTube and Instagram channels.
Dr. Bulsiewicz regularly covers specific dietary patterns and foods he links to chronic inflammation, as well as evidence-based alternatives that support gut health and reduce inflammatory markers. His content in this area draws on both microbiome research and his clinical experience with digestive disease patients.
Dr. B has pushed back on the framing that fiber and protein are competing priorities, arguing alongside other medical experts that you do not have to sacrifice one for the other. He positions adequate fiber intake as foundational to gut microbiome health even for people prioritizing high protein diets.
Gut Insiders appears to be a community or membership group associated with Dr. Bulsiewicz's brand, referenced in his hashtag usage. It likely gives followers deeper access to his gut health content, guidance, and potentially his 38TERA supplement ecosystem.
Dr. B covers the connection between circadian rhythm disruption and digestive and microbiome health, a growing area of clinical research. He translates findings from this field into practical lifestyle recommendations, making it one of the more science-forward topics he addresses compared to most wellness creators.
Dr. Will Bulsiewicz is a practicing, triple board-certified physician with certifications spanning gastroenterology and lifestyle medicine, plus over two decades of clinical experience. Unlike many wellness creators, his content is grounded in active clinical practice and peer-reviewed microbiome research rather than general lifestyle advice.
Stats (followers, engagement, audience demographics, growth) are pulled live from the CreatorDB API covering YouTube, Instagram and TikTok. Bio and FAQ content is AI-assisted; news items are sourced from cited public press at generation time. Read the full methodology →
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@theguthealthmd · YouTube
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