Who Developed Semaglutide — and Why It Took Four Decades

The decision Novo Nordisk made in the 1980s: bet on a gut hormone nobody had heard of

In the early 1980s, researchers identified a hormone secreted by cells in the small intestine whenever food arrived. They called it glucagon-like peptide-1, GLP-1. It did several interesting things at once: it prompted the pancreas to release insulin in response to meals, it slowed how quickly the stomach emptied, and it reduced appetite signals in the brain. On paper, a drug that mimicked it could treat type 2 diabetes and, potentially, help people eat less.

The obstacle was that the body breaks down natural GLP-1 within minutes of release. A medicine that lasted two minutes would not be practical. Novo Nordisk spent years testing modified versions (analogues) that could resist the enzymes responsible for that rapid destruction. The full story of how liraglutide and semaglutide were developed shows just how iterative this process was: each molecule taught the team something new about stability, receptor binding and tolerability.

A common misconception is that semaglutide was a sudden discovery, as if one team had a eureka moment in a laboratory. The reality is quieter and slower, a long chain of hypothesis, synthesis and clinical testing that ran across multiple research groups and decades.

How Novo Nordisk solved the half-life problem, and what makes semaglutide different from earlier GLP-1 drugs

Liraglutide, Novo Nordisk's first approved GLP-1 analogue, reached clinics in the late 2000s. It required daily injection. The scientists' next goal was a once-weekly version, which meant extending the molecule's half-life further still.

Their solution involved two modifications. First, they attached a fatty-acid chain to the semaglutide molecule so that it binds tightly to albumin, a protein abundant in the bloodstream. Albumin acts as a kind of slow-release depot, protecting the drug from enzymatic breakdown. Second, they made a small structural change at position 8 of the peptide chain (swapping one amino acid for another) to make it inherently more resistant to the main enzyme that destroys GLP-1. Together, these changes produced a half-life of roughly seven days, enough to sustain meaningful concentrations between weekly doses.

The development pathway for semaglutide went through an extensive clinical programme before any regulatory approval. The diabetes indication came first, Ozempic (also semaglutide, at lower maintenance doses) was approved for type 2 diabetes before the higher 2.4mg weight-management dose of Wegovy entered trials. The profile of semaglutide as a medicine spans both indications, though they are distinct products with different licensed uses.

From diabetes trials to Wegovy: when the weight-loss evidence became impossible to ignore

The weight-loss effects of GLP-1 drugs had been observed since the early trials, but the magnitude surprised many researchers. In the STEP 1 phase 3 trial (68 weeks, semaglutide 2.4mg versus placebo, alongside lifestyle changes) participants lost an average of around 15% of their body weight, as published in the New England Journal of Medicine. That figure was well beyond what earlier weight-loss medicines had achieved.

Novo Nordisk filed for a separate weight-management licence. The MHRA granted UK authorisation for Wegovy, and NICE subsequently recommended it for NHS use in certain circumstances under technology appraisal TA875. The NHS criteria are narrow (a specialist service, a maximum of two years, specific BMI and comorbidity thresholds) meaning most people who might benefit access it privately. For those exploring that route, understanding what Wegovy costs privately is a practical first step.

The oral formulation, Wegovy tablets, followed later: the MHRA approved the first oral GLP-1 medicine licensed in the UK for weight management in June 2026, adding a new option for people who prefer not to inject. Prescribers assess which format suits each patient individually.

What the story of semaglutide's development means if you're considering treatment today

Understanding where a medicine came from can help you assess whether to trust it. Semaglutide is not a new compound in a rush to market. It has been studied continuously since the early 2000s, initially in diabetes, then in weight management, and more recently in cardiovascular outcomes and liver disease. The evidence base is unusually deep for a weight-loss medicine.

None of that means it is right for everyone. Semaglutide is a prescription-only medicine for a reason: it has contraindications, drug interactions to consider, and a side-effect profile that needs discussing before starting. If you're curious about who made semaglutide and the organisation behind its creation, that background also matters when thinking about where your supply comes from, as the MHRA has warned repeatedly about counterfeit pens sold online, some containing entirely different substances. At nume, our clinical team reviews every consultation personally before any prescription is issued.

If you'd like to explore whether Wegovy could be appropriate for you, speak to our prescribers through a free consultation, there's no obligation, and you'll get a clinical view, not a sales pitch.