New injectable drugs for weight loss: what's in development?

Ready to take the next step? See if you're eligible for expert-led weight loss support.

Are you curious about the next new injectable drugs for weight loss? See what's currently in the pipeline.

If you've heard about Wegovy or Mounjaro, you'll know they've given people new hope when it comes to losing weight. These injectable drugs work by making you feel fuller faster, curbing cravings and helping you lose weight in a safe, sustainable way.

But they're not the end of the story.

Researchers are already testing what comes next – a new wave of weight loss drugs designed to work better, faster, or with fewer side effects. Some might eventually outperform Wegovy or Mounjaro. Others may simply offer more choice.

So, what's in the pipeline? And how close are we to seeing them on prescription in the UK?

Let's have a closer look.

Retatrutide: the 'Mounjaro Killer'?

Retatrutide is one of the most exciting new drugs in development – and it's already made headlines.

In a recent review of more than 15,000 people across dozens of trials, it outperformed every other medication studied, including Mounjaro and Wegovy. Some users saw up to 22.1% body weight reduction.

That's likely because retatrutide doesn't stop at mimicking one hormone – it mimics three.

Like Mounjaro, it targets GLP-1 and GIP. But it also adds a third hormone, glucagon, into the mix. Together, these signals may work more powerfully to control appetite and regulate blood sugar.

So, why isn't it available yet? Because those results came from a systematic review rather than a phase 3 trial. And before any drug can be prescribed in the UK, it must go through large-scale safety trials and get the green light from the MHRA.

In the meantime, Wegovy and Mounjaro remain the safest and most reliable options – and the ones we continue to offer at SemaPen.

Orforglipron: the first real pill alternative?

For some people, injections are a dealbreaker. That's where orforglipron could change things. Orforglipron is an oral (tablet-based) GLP-1 receptor agonist taken once daily.

So far, results have been encouraging. Phase 2 trials in adults with overweight or obesity have shown between 9% and 14.7% weight loss over 36 weeks. What's more, these trials have demonstrated a safety profile similar to common injectable weight loss drugs.

It hasn't outperformed the injectables yet. However, the tablet format could make medical weight loss treatments more accessible – especially for people who are managing multiple medications or prefer a non-injection option.

If licensed, orforglipron could be a great solution for people who want support without the weekly jab.

CagriSema: combining two powerful hormones

CagriSema is an injectable combination therapy that brings together semaglutide (the active ingredient in Wegovy) and a second hormone-like drug called cagrilintide.

Cagrilintide mimics amylin – a hormone that helps regulate satiety and glucose levels. When paired with semaglutide, the two appear to produce results that are better than the sum of their parts. In a recent trial, participants lost an average of 20.4% of their body weight by week 68, rivalling what we typically see with Mounjaro.

The idea behind CagriSema is simple: use two hormones that target different pathways so your body gets better at controlling hunger, digestion and metabolism.

CagriSema is not yet licensed in the UK – or anywhere, for that matter. However, since the drug is now in the phase 3 trial stage, we might not have to wait too long.

Survodutide: weight loss and liver health

Another new injectable drug for weight loss, survodutide, is still in early development. However, it's generating interest for more than just its weight loss potential.

Like retatrutide, it targets GLP-1 and glucagon for weight loss – but researchers are particularly excited about how it might help people with metabolic dysfunction-associated steatohepatitis (MASH).

MASH is a liver condition linked to obesity and insulin resistance. If survodutide can effectively treat weight and liver health in one go, it could offer dual benefits for people with complex needs.

That said, it's still early days. More trials are needed before we'll know how well it really performs.

GSBR-1290 and Danuglipron: early contenders

GSBR-1290 is another experimental GLP-1 drug that, like orforglipron, is taken orally.

In a phase 2a trial, participants achieved an average weight loss of 6.2% over 12 weeks. These are encouraging early results, but it's still too soon to know how it compares with orforglipron.

Picture of a scientist working at a computer in a lab.

Danuglipron, also a GLP-1 pill, looked promising at first. However, Pfizer discontinued development in April 2025 due to concerns about liver safety. It's a reminder that even the most exciting new treatments face strict safety standards – and not every candidate makes it to the finish line.

H3: What makes a new weight loss drug worth watching?

Big numbers are eye-catching – but there's more to a good weight loss drug than dramatic before-and-after photos.

Regulators look for medications that help people lose safely and sustainably. And if they come with other health benefits – like improved blood sugar, cholesterol or liver function – that's even better.

H3: Are Wegovy and Mounjaro still the best options?

Right now – and for most patients – yes. These are the most effective and well-tested GLP-1 medications currently available through private prescription in the UK.

Here's what the research shows:

People using semaglutide (Wegovy) lose an average of 14.9% of their body weight over 68 weeks.
People using tirzepatide (Mounjaro) lose up to 21% – one of the best results seen in approved obesity treatments to date.

These injections are already helping thousands of people improve their health and take better control of their weight. While drugs like retatrutide and CagriSema show real promise, they're still in development and are not yet available in the UK.

H3: How SemaPen can help

At SemaPen, we offer more than just medication. Our non-surgical weight loss programmes combine trusted, clinically proven treatments with personalised support from obesity experts, so you're never left to figure things out alone.

Whether you're starting your journey or switching from another provider, you'll receive a full medical assessment and regular check-ins to help keep you on track. You'll also get a smart scale that connects directly to your care team so they can follow your progress in the cloud.

We can prescribe either Wegovy or Mounjaro – depending on what's right for you. Most importantly, we'll work with you to make sure the treatment fits into your life, not the other way around.

Thinking of starting your journey or switching from another provider? You can get started today by taking our simple online consultation.

Sources

1. Moiz, A. et al. (2025) "Efficacy and Safety of Glucagon-Like Peptide-1 Receptor Agonists for Weight Loss Among Adults Without Diabetes: A Systematic Review of Randomized Controlled Trials" Annals of Internal Medicine, 178(2) https://doi.org/10.7326/ANNALS-24-01590

2. Wharton, S. et al. (2023) "Daily Oral GLP-1 Receptor Agonist Orforglipron for Adults with Obesity" The New England Journal of Medicine, 389(10) https://doi.org/10.1056/nejmoa2302392

3. Garvey, W.T. et al. (2025) "Coadministered Cagrilintide and Semaglutide in Adults with Overweight or Obesity" The New England Journal of Medicine https://doi.org/10.1056/NEJMoa2502081

4. Wilding, J.P.H. et al. (2021) "Once-weekly semaglutide in adults with overweight or obesity" The New England Journal of Medicine, 384(11) https://doi.org/10.1056/NEJMoa2032183

5. Jastreboff, A.M. et al. (2022) "Tirzepatide Once Weekly for the Treatment of Obesity" The New England Journal of Medicine, 387(3) https://doi.org/10.1056/NEJMoa2206038

This article was reviewed and approved by Lujain Alhassan, Bariatric Nutritionist, and Alice Fletcher, Lead Bariatric Dietitian, on 7 July 2025.

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