Who Discovered Semaglutide — and How Did It Become a Weight-Loss Medicine?

Which scientists and company are behind semaglutide's discovery?

The story begins not with semaglutide itself, but with a hormone. In the early 1980s, researchers identified glucagon-like peptide-1 (GLP-1) in the cells lining the small intestine. GLP-1 is released after eating; it signals to the brain that food has arrived, slows the emptying of the stomach, and prompts the pancreas to release insulin when blood sugar rises. Scientists at Novo Nordisk and in academic centres across the US and Europe recognised that mimicking this signal artificially could have profound effects on both diabetes and body weight.

The challenge was biological. Natural GLP-1 is destroyed in the bloodstream within minutes. Novo Nordisk's chemists spent years engineering analogues, molecules similar enough to GLP-1 to activate the same receptors, but chemically altered to last longer in the body. The first major result was liraglutide, a once-daily GLP-1 analogue. A detailed account of that journey is set out on the page covering the development of liraglutide and semaglutide. Semaglutide came next, using a modified fatty-acid attachment that binds loosely to albumin in the blood, extending its life long enough for once-weekly dosing. That single structural shift changed what was practical for patients entirely.

The name most associated with the wider GLP-1 field is Professor Jens Juul Holst, a Danish physiologist whose foundational work on GLP-1 in the 1980s at the University of Copenhagen gave Novo Nordisk's chemists the biological target to work towards. If you want to explore the full scientific story, our page on how semaglutide was discovered traces that research in more detail. Semaglutide's development then drew on a broader team of Novo Nordisk pharmacologists, endocrinologists and clinical scientists across more than a decade of iterative work.

How did semaglutide go from a diabetes drug to a weight-loss medicine?

Semaglutide was initially developed for type 2 diabetes, licensed first as Ozempic (0.5mg and 1mg weekly injections). During those diabetes trials, researchers noticed something consistent: participants were losing meaningful amounts of weight, well beyond what the glucose control alone would explain. That observation drove a dedicated clinical programme targeting obesity, the STEP trials.

STEP 1, a 68-week randomised controlled trial involving over 1,900 adults with obesity or overweight and at least one weight-related condition, found that semaglutide at the 2.4mg maintenance dose produced around 15% average reduction in body weight compared with placebo. The results were published in the New England Journal of Medicine and supported regulatory applications in multiple countries. NICE subsequently recommended Wegovy for NHS use in eligible adults under its technology appraisal TA875, though NHS access remains limited to specialist weight management services with long waiting lists.

The oral form of semaglutide for weight loss (Wegovy tablets) received MHRA approval in June 2026, making the UK the first country in Europe to license an oral GLP-1 medicine specifically for weight management. The science that made tablets possible involved co-formulating semaglutide with an absorption enhancer called SNAC, which protects the molecule from stomach acid long enough for it to reach the bloodstream. More on how semaglutide works as a medicine is covered in full on the semaglutide overview page.

Why does the discovery matter for people considering treatment today?

Understanding where semaglutide came from is more than a history lesson. The decades of research behind it explain why weight specialists treat obesity as a biological condition with a hormonal basis, not a discipline problem. GLP-1 receptors exist throughout the brain and gut precisely because the body has its own architecture for regulating appetite; semaglutide borrows that architecture and amplifies it.

It also explains why a prescription and clinical oversight are genuinely important, not regulatory box-ticking. The dose escalation schedule (starting low and increasing gradually) was designed in the Novo Nordisk trials specifically to reduce gastrointestinal side effects while the body adjusts. A prescriber who understands that science adapts the pace if you are struggling. Someone selling semaglutide without proper clinical assessment cannot make those judgements. If you are wondering how the cost of treatment breaks down, the cost context for Wegovy in the UK is worth reading alongside the clinical picture.

The MHRA continues to monitor semaglutide's safety profile through its Black Triangle scheme, meaning any new signals from real-world use are collected and reviewed systematically. Patients can contribute to that process directly by reporting unexpected side effects via the Yellow Card scheme. That feedback loop is part of what responsible, long-term use of a relatively new medicine looks like. Patients sometimes also ask about specific physical changes during treatment, and our page on whether Wegovy helps with water retention addresses one of the more common questions we receive on that topic.

Our clinical team has a background page if you want to understand who oversees prescribing at nume, and broader context on how we approach weight management is on the weight loss overview. If you have a question that this page hasn't answered, our FAQs cover the topics patients ask us about most often.

If you would like to find out whether semaglutide treatment is clinically suitable for you, speak to our prescribers through a free consultation, reviewed the same day by a GPhC-registered Independent Prescriber.