Future Weight Loss
Treatments 2026–2028

The weight loss medication revolution is just beginning

Wegovy and Mounjaro have transformed obesity treatment, but they represent only the first wave of a rapidly evolving field. At least five next-generation candidates are progressing through clinical development, each offering potentially superior efficacy, different mechanisms, or more convenient administration. Several may reach UK patients between 2027 and 2029.

This guide provides a factual overview of the most advanced candidates based on published clinical trial data and company announcements. All timelines are estimates and subject to regulatory outcomes.

Survodutide (Boehringer Ingelheim)

What is it?

Survodutide is a dual glucagon/GLP-1 receptor agonist. Unlike Mounjaro, which targets GIP and GLP-1 receptors, survodutide activates the glucagon receptor alongside GLP-1. Glucagon receptor activation increases energy expenditure and promotes fat oxidation — the body burns more fat directly, adding a distinct mechanism to the appetite suppression provided by GLP-1.

Clinical trial results

• Phase 2 (published 2024): In a 46-week trial of 387 adults with obesity, the highest dose of survodutide produced mean weight loss of approximately 18.7% compared with 2.1% for placebo
• MASH benefit: Survodutide has also shown significant efficacy in metabolic dysfunction-associated steatohepatitis (MASH, formerly known as NASH), with a phase 2 trial demonstrating histological resolution in a substantial proportion of participants
• Side effects: Gastrointestinal side effects (nausea, diarrhoea, vomiting) were the most common, consistent with other incretin-based therapies. Heart rate increases were observed, as expected with glucagon receptor activation

UK timeline

Phase 3 trials are ongoing. Regulatory submission to the MHRA is not expected before 2028 at the earliest, with potential UK availability from 2029 if trials succeed and regulatory review is favourable.

Retatrutide (Eli Lilly)

What is it?

Retatrutide is a triple hormone receptor agonist, activating GIP, GLP-1 and glucagon receptors simultaneously. It is manufactured by Eli Lilly, the same company behind Mounjaro. If Mounjaro is a dual agonist, retatrutide adds a third mechanism — glucagon receptor activation — to the equation.

Clinical trial results

• Phase 2 (published 2023): In a 48-week trial of 338 adults with obesity, the highest dose (12 mg) produced mean weight loss of approximately 24.2% — the greatest ever reported for any anti-obesity medication in a randomised trial
• Participants losing ≥25%: Approximately 34% of participants on the highest dose lost at least a quarter of their body weight
• Type 2 diabetes subgroup: Substantial weight loss and glycaemic improvement were also observed
• Side effects: Similar gastrointestinal profile to other GLP-1-based medications. Nausea, diarrhoea and vomiting were most common during dose escalation

UK timeline

Eli Lilly has initiated the phase 3 TRIUMPH programme. These large-scale trials are expected to read out from late 2026 through 2027. If results confirm the phase 2 findings, regulatory submissions could follow in 2027–2028, with potential MHRA approval and UK availability from 2028–2029.

Orforglipron (Eli Lilly)

What is it?

Orforglipron is a small-molecule, oral, non-peptide GLP-1 receptor agonist. Unlike current GLP-1 medications which are injectable peptides that must be refrigerated and administered via subcutaneous injection, orforglipron is a daily pill taken by mouth. This represents a fundamental change in how GLP-1 therapy could be delivered.

Why an oral pill matters

• Needle aversion: A significant proportion of potential patients avoid injectable treatments due to needle phobia or discomfort
• Convenience: No cold-chain storage, no injection devices, no sharps disposal
• Manufacturing: Small-molecule pills are generally cheaper and easier to manufacture at scale than biological peptides
• Access: Potentially lower cost could expand access through both the NHS and private prescriptions

Clinical trial results

• Phase 2 (published 2023): In a 36-week trial of 272 adults with obesity (without diabetes), orforglipron 45 mg produced mean weight loss of 14.7%, compared with 2.3% for placebo
• Type 2 diabetes trial: Orforglipron produced mean HbA1c reduction of approximately 2.1% and mean weight loss of 9.4% at 26 weeks in patients with type 2 diabetes
• Side effects: Gastrointestinal side effects were common but generally mild to moderate. Tolerability improved with gradual dose escalation

UK timeline

Phase 3 trials (ACHIEVE programme) are underway. Results are expected from 2026–2027. Regulatory submission to the MHRA could follow in 2027, with potential UK availability from 2028. Oral semaglutide (a different oral formulation by Novo Nordisk) has already received MHRA approval for type 2 diabetes, demonstrating that oral GLP-1 delivery is feasible.

Amycretin (Novo Nordisk)

What is it?

Amycretin is a novel co-agonist that combines GLP-1 receptor activity with amylin receptor activity in a single molecule. Amylin is a hormone naturally co-secreted with insulin by pancreatic beta cells. It promotes satiety, slows gastric emptying and reduces glucagon secretion. By combining GLP-1 and amylin receptor activation, amycretin targets appetite through complementary pathways.

Clinical trial results

• Phase 1/2 (reported 2024): Early-stage data showed mean weight loss of approximately 13% after just 12 weeks of treatment — an unusually rapid rate of weight loss at this early stage
• Projected efficacy: Based on the early weight loss trajectory, analysts and researchers have projected that amycretin could produce weight loss exceeding 25% at 52–68 weeks if the rate is sustained
• Subcutaneous and oral: Novo Nordisk is developing both injectable and oral formulations

UK timeline

Amycretin is earlier in development than the other candidates on this list. Phase 2 trials are ongoing. Regulatory submissions are unlikely before 2028–2029, with potential UK availability from 2029–2030 at the earliest.

CagriSema (Novo Nordisk)

What is it?

CagriSema is a fixed-ratio combination of semaglutide 2.4 mg (the active ingredient in Wegovy) and cagrilintide, a long-acting amylin analogue, administered as a single once-weekly injection. Rather than engineering a new molecule, CagriSema combines two proven drugs to enhance efficacy.

Clinical trial results

• Phase 2 (published 2024): CagriSema produced mean weight loss of approximately 22.7% at 68 weeks, compared with 15.8% for semaglutide alone and 8.1% for cagrilintide alone
• Responder analysis: A substantial proportion of participants achieved weight loss exceeding 25%
• Tolerability: The safety profile was broadly consistent with semaglutide alone, though gastrointestinal side effects were slightly more frequent

UK timeline

Phase 3 trials (REDEFINE programme) are underway. Novo Nordisk has indicated that data is expected in 2026. If results are positive, regulatory submission could follow later in 2026 or early 2027, with potential MHRA approval and UK availability from 2027–2028.

Comparison table: pipeline medications at a glance

What this means for UK patients

The obesity treatment pipeline is more active now than at any point in pharmaceutical history. For UK patients currently on Wegovy or Mounjaro, the immediate implications are limited — these new treatments are still in development. However, within the next two to four years, the treatment landscape is likely to expand substantially.

Key themes to watch

• Greater efficacy: Retatrutide and CagriSema may deliver weight loss approaching 25%, moving closer to what was previously only achievable through bariatric surgery
• Oral options: Orforglipron could remove the injection barrier, potentially doubling the number of patients willing to try pharmacological weight management
• Multi-disease treatment: Survodutide’s dual benefit for obesity and MASH exemplifies a trend towards treating metabolic conditions as interconnected rather than separate
• NHS access questions: As more options become available, NICE appraisals will determine which medications are cost-effective for NHS use. Cost, supply capacity and commissioning structures will all influence real-world access
• Muscle preservation: Regardless of which medication is used, the challenge of lean mass loss remains. Exercise and protein strategies will be just as important with next-generation treatments

Frequently asked questions

When will retatrutide be available in the UK?

The earliest realistic estimate for UK availability of retatrutide is 2028–2029, contingent on positive phase 3 results, MHRA approval and NICE appraisal. Phase 3 trials are expected to read out from late 2026 through 2027.

Will there be a weight loss pill available on the NHS?

Orforglipron, if approved, would be the most likely candidate for an oral GLP-1 weight loss medication available on the NHS, potentially from 2028. Oral semaglutide already has MHRA approval for type 2 diabetes and a submission for weight management is expected. NICE will need to appraise cost-effectiveness before NHS availability is confirmed.

Should I wait for these new medications instead of starting Wegovy or Mounjaro now?

No. If you are eligible for treatment with Wegovy or Mounjaro and your clinician recommends it, there is no clinical reason to wait for medications that are still years from approval. Obesity carries ongoing health risks, and the benefits of available treatments are well established. You can always discuss switching to newer options with your prescriber if and when they become available.

Will these new treatments be more expensive?

Pricing is not yet established for any pipeline medication. Historically, newer medications tend to launch at premium prices, though competition in the obesity market may moderate this. Oral options like orforglipron could be cheaper to manufacture, potentially offering cost advantages. NHS pricing will be determined through NICE technology appraisals.