Dr. Karan Rajan

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Dr Karan Rajan is an NHS general surgeon, founder of microbiome-supplement company LOAM Science, and one of the most-followed health and science creators online. He has more than 10 million followers across TikTok, YouTube, Instagram and Facebook, alongside his clinical work in the NHS and a role as honorary clinical lecturer at the University of Sunderland.

His online presence began in 2012 as a medical student at Imperial College London, where he posted YouTube tutorials on practical exams. The audience grew sharply during the 2020 lockdowns when he began using short-form video to debunk health misinformation. The tone — frank, evidence-based, and deliberately irreverent — has carried him into broadcast: BBC Morning Live, Good Morning Britain, Sky News and BBC News, plus a co-presenting credit on BBC Two's "Your Body Uncovered."

His Sunday Times bestseller "This Book May Save Your Life" was published in January 2024. In November 2025 he launched LOAM Science, a prebiotic-fiber supplement company that came out of two years of testing and went to market with a waitlist of nearly 40,000. He also hosts a podcast and newsletter on gut health, writes a column for Mail+, and has worked with the NHS and Cabinet Office on public health campaigns including COVID-19 vaccination uptake among 16–25s.