How old is semaglutide, and why does its age matter now?

You've heard about semaglutide everywhere lately — but it's been around longer than you think

If you've only started hearing about semaglutide in the last couple of years, you'd be forgiven for assuming it's brand new. It isn't. Novo Nordisk began developing GLP-1 receptor agonists as diabetes medicines in the early 2000s, building on liraglutide (Victoza, Saxenda) and working towards a longer-acting, once-weekly molecule. That molecule became semaglutide.

The first regulatory approval landed in the United States in December 2017, for type 2 diabetes under the brand name Ozempic. European and UK approvals followed, also for diabetes. At that stage, weight management wasn't part of the licence at all. Ozempic remains, to this day, licensed for type 2 diabetes rather than weight loss, a distinction that matters enormously, and one that our semaglutide overview explains in full.

What changed everything was a dedicated obesity trial programme. STEP 1, published in the New England Journal of Medicine in 2021, randomised adults with obesity to 2.4mg semaglutide or placebo for 68 weeks. The average weight reduction in the treatment group was around 15%, a figure that shifted how clinicians, regulators and patients thought about medical weight management. That evidence drove the weight-loss licence.

If you're curious about how the science behind the molecule was actually put together in a lab, the manufacturing process for semaglutide is its own fascinating story.

When semaglutide became Wegovy: the UK weight-loss timeline

Novo Nordisk submitted Wegovy (the weight-management brand of semaglutide at 2.4mg) for UK approval while global supply was still catching up with demand. The MHRA granted a UK licence in 2021. That was the regulatory green light; actually getting it onto shelves, and onto the NHS, took longer.

NICE published its technology appraisal recommending semaglutide (TA875) in March 2023, but with strict conditions: use only within a specialist weight management service with multidisciplinary support, for a maximum of two years, and only for adults with a BMI of 35 or above alongside at least one weight-related condition (thresholds are 2.5 kg/m² lower for some ethnic backgrounds under UK guidance). NHS waiting lists for those services remain long in many areas.

The approval story didn't stop there. In January 2026, the MHRA approved a higher 7.2mg maintenance dose, and by April 2026, a dedicated single-dose 7.2mg pen had received the go-ahead. If you want the full picture of how Wegovy's approval history unfolded, that page covers it step by step.

Then, on 11 June 2026, the MHRA approved the first oral semaglutide tablet for weight management in the UK, marketed as Wegovy tablets. The Wegovy treatment page covers both the injection and the tablet in detail.

How storage requirements reflect the molecule's age and formulation

One practical consequence of semaglutide's decade-plus development history is a well-understood stability profile. The injection requires refrigeration between 2°C and 8°C, most people keep it in the fridge door, which works fine as long as temperatures stay stable. The Patient Information Leaflet specifies the exact room-temperature window for when you're travelling or away from a fridge; always check that rather than going from memory, since the window is shorter than many assume. You can find links to the full prescribing information via the guide to semaglutide and cold storage.

The oral tablet, by contrast, needs no refrigeration at all, it's kept at room temperature, which makes it considerably more travel-friendly. Both formulations are well past the early trial stages; the stability data behind them is mature, not provisional.

Understanding the age of the evidence base also means understanding its depth. The NICE appraisal of semaglutide (TA875) drew on years of accumulated safety reporting, not just a single short-term trial. That breadth of data is part of what supports the medicine's current regulatory status in the UK.

What the molecule's history means for anyone considering treatment today

Semaglutide being a decade-old molecule matters in one specific way: there is now a substantial body of post-marketing data, not just controlled-trial results. Regulatory agencies including the MHRA have accumulated real-world safety signals, updated prescribing guidance and issued targeted communications (including a Drug Safety Update in January 2026 on pancreatitis risk) that reflect genuine pharmacovigilance over time, not just pre-approval monitoring.

None of that makes semaglutide trivial to take. It remains a prescription-only medicine. A prescriber needs to assess your health history, current medicines, and whether the injection or tablet is the better fit before anything is dispensed. The age of the treatment context (including the newer tirzepatide evidence) is worth understanding before making that decision, and the weight-loss treatment overview sets out the current options side by side.

The minimum age for Wegovy is a separate, frequently asked question: the medicine is not currently licensed for under-18s in the UK, which is one of the things a clinical review will confirm. If you'd like to explore whether semaglutide could be appropriate for you, our prescribers review every consultation personally. You can check your eligibility with a free consultation, no waiting list, reviewed the same day.