How Long Have Semaglutides Been Around — and What Has Changed?

Where did semaglutide actually come from?

The story starts with a lizard. In the 1980s, scientists studying the Gila monster discovered that its saliva contained a peptide (exendin-4) that mimicked GLP-1, a hormone the human gut releases after eating to signal fullness and stimulate insulin. That finding kicked off a decades-long effort to create a stable, injectable version of GLP-1 that could last long enough to be useful as a medicine.

Novo Nordisk developed semaglutide as a once-weekly GLP-1 receptor agonist, an improvement on earlier daily injections like liraglutide. The key chemical modification was attaching the molecule to a fatty-acid chain that binds to albumin in the blood, extending its half-life to roughly a week. Clinical trials for the diabetes indication ran through the 2010s, and the medicine received its first approval (for type 2 diabetes, sold as Ozempic) in the United States in December 2017, followed by UK and European approvals shortly after.

It is worth being precise here: Ozempic and the oral diabetes tablet Rybelsus are both semaglutide, but they are licensed specifically for type 2 diabetes management, not for weight loss. Wegovy is the separate, higher-dose formulation developed and licensed specifically for weight management, a distinction that matters both clinically and legally.

When did semaglutide become a licensed weight-loss medicine in the UK?

The phase 3 STEP programme, which tested semaglutide 2.4mg weekly against placebo in adults with obesity, reported its headline results in the New England Journal of Medicine in 2021. STEP 1 found an average body-weight reduction of around 15% over 68 weeks, a result that shifted clinical thinking about what weight-management medicines could achieve.

Regulatory approvals followed. NICE recommended semaglutide (Wegovy) for NHS use in March 2023, under specific criteria that include treatment within a specialist weight management service and a maximum duration of two years. The private market opened up the same period. If you are curious about exactly when Wegovy became available in the UK, that page goes into the launch timeline in more detail.

Since the initial 2.4mg launch, the semaglutide story has kept moving. The MHRA approved a 7.2mg maintenance dose in January 2026, and a dedicated single-dose 7.2mg pen followed in April 2026, trials reported around 20.7% average weight loss at that higher dose over 72 weeks, narrowing the gap with the newer dual-agonist medicines. People often ask how fast semaglutides work, and the answer varies depending on the dose, the formulation, and how your body responds in those early weeks. If you want to understand how long semaglutide takes to work and how long its effects last, the picture is more nuanced than headlines suggest.

What changed most recently, and why does it matter?

June 2026 brought the biggest structural change to the semaglutide story since Wegovy launched: the MHRA approved Wegovy tablets, making semaglutide the first oral GLP-1 medicine licensed in the UK for weight management. The tablet uses an absorption enhancer called SNAC to get the molecule across the gut wall, taken first thing in the morning before food. The dosing ladder runs from 1.5mg up to a 25mg maintenance dose, completely separate from the Rybelsus diabetes tablet strengths. Phase 3 trial data (OASIS 4, 64 weeks) showed around 13.6% average weight loss versus placebo, and roughly 17% among participants who stayed fully adherent to treatment.

The MHRA also granted semaglutide a conditional approval in July 2026 for a form of fatty liver disease (MASH), extending the medicine's reach beyond weight management altogether. You can read the official announcement on GOV.UK.

All of this matters for anyone considering treatment now, because it means there are genuinely more options than there were even twelve months ago: injection or tablet, standard or higher-dose, and a growing body of evidence behind each. Choosing between them is a clinical conversation. Our clinical team reviews each consultation personally, a prescriber, not software, reads your answers and decides what is appropriate for you. If cost is part of your thinking, Wegovy pricing is one of the more common questions we get, and it is worth understanding what a legitimate private prescription actually includes before comparing figures.

How does the length of semaglutide's track record affect treatment decisions today?

Twenty-plus years of research and nearly a decade of real-world prescribing for the diabetes formulation means the long-term safety profile is better understood than for newer molecules. That said, Wegovy itself remains on Black Triangle (▼) status with the MHRA, meaning adverse effects are still being actively collected, which is not a reason for alarm, but it is a reason to stay connected to a prescriber throughout treatment. The NHS patient page on semaglutide sets out the known side-effect profile clearly.

The length of time someone needs to stay on treatment is a separate question from how long the medicine has existed, and it is one our prescribers discuss at every review. Many people wonder how long they will need to keep taking Wegovy, and the answer depends on factors your prescriber will work through with you over time. Similarly, stopping Wegovy abruptly carries its own considerations that are worth reading about before making any change. And if you are weighing up how to get started, speaking to our prescribers is a good first step.