Medical weight loss · UK
Retatrutide, honestly - not yet licensed in the UK.
The triple agonist that reached 24.2% mean weight loss in Phase 2. Currently unlicensed anywhere. What you can do now, how to join a trial, and how to register interest for launch with a reputable clinic.
Why patients choose us
- 01
Honest about what is licensed today
Retatrutide is not yet approved by the MHRA or FDA. We will not prescribe it off-label from unregulated sources, and we will tell you what is proven now.
- 02
A pathway to the licensed options that work
While retatrutide moves through Phase 3, Wegovy and Mounjaro are the current best-evidence choices. We arrange those, with monitoring, today.
- 03
A place on the waiting list when it launches
Register interest with a reputable specialist clinic. When licensure lands, expected 2026 to 2027, you get an early consultation slot.
The situation
The most effective weight-loss drug in trials, not available to prescribe.
Retatrutide, Eli Lilly LY3437943, is a once-weekly injectable that agonises GIP, GLP-1 and glucagon receptors together. Phase 2 TRIUMPH showed 24.2% mean weight loss at 48 weeks on 12 mg. Phase 3 is ongoing. It has no marketing authorisation anywhere as of 2026.
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Wanting to skip ahead to retatrutide?
Understandable, but the only medically supervised route in the UK today is a clinical trial. Any other supply is unregulated.
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Ready to start now with a licensed drug?
Wegovy at 15% and Mounjaro at 22% mean weight loss are the current best-evidence, MHRA-licensed options.
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Just wanting to be first in the queue?
A reputable clinic will take an interest registration and hold a launch consultation slot when licensure lands.
The path
From today to a licensed retatrutide programme.
The three sensible things to do now, and the four things that follow once MHRA approval lands.
- 01 Now
Understand what retatrutide is
Eli Lilly LY3437943, a triple agonist of GIP, GLP-1 and glucagon receptors. Phase 2 TRIUMPH showed 24.2% mean weight loss at 48 weeks on the 12 mg dose.
- 02 Now
Confirm current UK licensing status
As of 2026 retatrutide is not licensed anywhere. FDA approval is expected in 2026, MHRA is likely to follow. It cannot be prescribed for weight loss in the UK today.
- 03 Now
Consider a licensed alternative now
Wegovy (semaglutide) delivers around 15% weight loss. Mounjaro (tirzepatide) delivers around 22%. Both are licensed, monitored, and available through a specialist clinic.
- 04 Now
Or explore a clinical trial
The Phase 3 TRIUMPH programme has active UK sites, but places are limited and eligibility is tight. We can point you toward Eli Lilly recruiting centres.
- 05 On launch
Register interest for licensed launch
When retatrutide clears MHRA review, expect a Wegovy-style structured programme: consultant assessment, baseline bloods, monthly titration and dietitian support.
- 06 On launch
Consultant assessment on launch
Bariatric physician or endocrinologist appointment, medical history, BMI, comorbidities, cardiac and thyroid history, contraindication screening.
- 07 On launch
Long-term monitoring plan
Monthly check-ins during titration, quarterly bloods, dietitian review, behavioural coaching. A GLP-1 class drug is a long-term commitment, not a quick course.
Who it may help
Who the drug is likely licensed for, and who it will not be for.
Based on trial recruitment and typical class licensure. Not a substitute for a consultant assessment.
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BMI over 30, or over 27 with a comorbidity
The population that trials have recruited, and the population MHRA is likely to license the drug for on approval.
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Semaglutide or tirzepatide plateau
Patients who have responded to a GLP-1 or dual agonist but stalled short of goal - a candidate group for a triple agonist once licensed.
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Metabolic syndrome and fatty liver
Early signals suggest strong hepatic fat reduction with retatrutide, of interest for MASH and metabolic-associated liver disease.
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Type 2 diabetes with obesity
Trial subgroups showed meaningful HbA1c reduction alongside weight loss - but a diabetes licence is a separate regulatory step.
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Post-bariatric weight regain
A common reason patients look for pharmacological help. Licensed GLP-1 options should be tried first while retatrutide is not yet available.
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Cardiovascular risk reduction
Outcome data on major adverse cardiac events is not yet mature for retatrutide. Semaglutide has that outcome data now.
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Not appropriate: cosmetic weight loss
GLP-1 class drugs are not cosmetic. If BMI is under 27 with no comorbidity, no reputable clinic will prescribe them, including once retatrutide launches.
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Red flag: grey-market retatrutide online
Vials sold as retatrutide online are almost always research-grade compounded product with no MHRA oversight. Do not use them - the safety risks are real and unquantified.
The wider option set
Retatrutide, in context - what is on the shelf today.
Weight-loss ranges are trial averages, not individual guarantees. Numbers are lower without a coached programme, and higher with sustained lifestyle change.
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Wegovy (semaglutide) 2.4 mg
Licensed weekly GLP-1 injection. Around 15% mean weight loss at 68 weeks in STEP-1. The most established option, with mature cardiovascular outcome data.
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Mounjaro (tirzepatide) 5 to 15 mg
Licensed weekly dual GIP and GLP-1 agonist. Around 20 to 22% mean weight loss at 72 weeks in SURMOUNT-1. Currently the strongest licensed option in the UK.
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Retatrutide (LY3437943) 12 mg
Triple GIP, GLP-1 and glucagon agonist. 24.2% mean weight loss at 48 weeks in Phase 2 TRIUMPH. Not yet licensed. Phase 3 ongoing.
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Saxenda (liraglutide) 3 mg daily
Older licensed daily GLP-1. Around 8% mean weight loss. Superseded by weekly options for most patients but still useful in selected cases.
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Allurion swallowable balloon
A four-month intragastric balloon, swallowed rather than endoscopically placed. Around 10 to 15% weight loss when paired with a coached programme.
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Endoscopic sleeve gastroplasty (ESG)
A day-case endoscopic gastric reshaping. Around 15 to 18% weight loss at one year, no incisions, no permanent implant.
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Bariatric surgery
Sleeve gastrectomy or Roux-en-Y bypass, 25 to 30% mean weight loss at two years and the most durable option, with the highest procedural commitment.
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Clinical trial enrolment
The only current route to retatrutide with proper medical oversight, monitoring, drug provenance and adverse event reporting. UK sites are limited.
London providers on launch
Where we expect a licensed programme to run.
Established specialist obesity centres with existing GLP-1 pathways. Introductions are made privately once retatrutide is licensed and our network confirms availability.
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Cleveland Clinic London obesity service
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HCA The Wellington bariatric medicine
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King’s Private endocrinology and diabetes
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Voy Health medical weight-loss programme
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Independent London bariatric physicians
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Consultant bariatric physicians and endocrinologists, not nurse-led pop-up clinics
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MHRA-registered pharmacy supply chain for every drug prescribed
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Structured monitoring: monthly titration, quarterly bloods, dietitian and behavioural support
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No off-label supply of unlicensed compounded retatrutide, ever, from any source
Safety, plainly
What is known, what is not, and what to avoid.
Retatrutide has a strong Phase 2 dataset but nothing like the real-world safety record of semaglutide. Grey-market compounded product is a category we advise against without exception.
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Retatrutide is not licensed in the UK
As of 2026 no regulator has approved retatrutide for weight loss. Any UK supply outside a clinical trial is unregulated by definition.
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Grey-market retatrutide is a real risk
Vials sold online as research chemical are not sterile, not dose-verified, have no manufacturer support and no adverse-event tracking. No UK medical body endorses their use.
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Expected GI side effects
Based on Phase 2 data, expect nausea, vomiting, diarrhoea, constipation and delayed gastric emptying, similar to the GLP-1 and dual-agonist class.
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Glucagon activation is the new variable
The glucagon arm of retatrutide is what differentiates it. Long-term effects on heart rate, hepatic glucose output and lean-mass loss are not yet fully characterised.
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Cardiovascular outcome data pending
Semaglutide has published MACE outcome data. Retatrutide does not, yet. If cardiovascular risk reduction is your priority, semaglutide is the current evidence-based choice.
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Not a short course
Weight regain on stopping is expected across the GLP-1 class. Any programme, present or future, is a multi-year commitment with a maintenance dose plan.
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Baseline and monitoring bloods
A responsible programme starts with HbA1c, lipids, renal, liver, thyroid, pregnancy status where relevant, and repeats quarterly.
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Contraindications to know now
Personal or family history of medullary thyroid carcinoma, MEN2, active pancreatitis, pregnancy or planning pregnancy, severe gastroparesis. These will apply to retatrutide too.
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Register interest, do not self-source
The safe path is a waiting-list slot with a reputable clinic. The unsafe path is buying from an online reseller. We will not help with the second.
Your personal plan
A short plan in four parts. Read the last one first.
We put a written plan on file whether you start a licensed drug now, join a trial or wait for launch.
- 01 Header
Regulatory status and expected launch
A clear note of the current licensure position, expected FDA and MHRA timelines, and what has changed since your last review.
- 02 Options
Licensed alternatives available today
Which of Wegovy, Mounjaro, Saxenda, Allurion or ESG fits your BMI, comorbidities and preference, with expected weight-loss ranges.
- 03 Trials
Open UK research studies
Where TRIUMPH Phase 3 sites are recruiting, eligibility criteria and how to make contact.
- 04 Plan
Interest register and launch pathway
Read this first: what happens if you want a slot the moment retatrutide is licensed, and what data your consultant will need on day one.
Recognised by major UK insurers
Most insurers do not fund weight-loss drugs. Cover is more likely with type 2 diabetes or an obesity-related comorbidity. We confirm before booking.
Frequently asked
The six questions we get about retatrutide.
Straight answers on licensure, grey-market risk, trials, cost, and how it compares to Mounjaro.
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When will retatrutide be licensed in the UK?
FDA approval is expected during 2026 based on the Phase 3 TRIUMPH timeline. MHRA usually follows within 6 to 18 months. Realistic UK availability through licensed private clinics is late 2026 to 2027, and NHS access will lag further behind.
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Is grey-market retatrutide sold online safe?
No. Vials sold online as retatrutide research chemical are not licensed, not sterile-guaranteed, not dose-verified and have no manufacturer support. There is no adverse-event tracking and no recourse if something goes wrong. No UK medical body, and no reputable UK clinic including ours, endorses their use. The safety risks are real and unquantified.
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What can I do now for medical weight loss?
Two licensed options with mature evidence. Wegovy (semaglutide 2.4 mg) delivers around 15% mean weight loss at 68 weeks. Mounjaro (tirzepatide) delivers around 20 to 22% at 72 weeks. Both are prescribed under a structured programme with a bariatric physician, monthly titration and dietitian support. Endoscopic options like ESG and Allurion are also available.
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Can I join a retatrutide clinical trial?
The Phase 3 TRIUMPH programme has recruiting sites, including a limited number in the UK. Eligibility is specific: BMI thresholds, comorbidity profile, exclusion criteria for prior GLP-1 use in some arms. We can direct you to Eli Lilly recruiting centres, but we do not run the trial ourselves.
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What will a UK retatrutide programme cost when it launches?
It is too early to quote firm figures. As a reference, Mounjaro currently runs £150 to £300 per month depending on dose and clinic, plus consultation and monitoring fees. Retatrutide will likely price at the top end of that range or above on launch. Register interest and we will share firm pricing when it is known.
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How does retatrutide compare to Mounjaro?
In head-to-head trial context, Mounjaro delivered around 22% mean weight loss (SURMOUNT-1, 72 weeks) and retatrutide delivered around 24.2% (TRIUMPH Phase 2, 48 weeks). Side effect profiles look broadly similar in the GI domain, with retatrutide adding a glucagon axis whose long-term effects are still being characterised. The important difference today is licensure: Mounjaro is available, retatrutide is not.
Register interest
A slot on the waiting list, or a licensed alternative today.
Send one message. We come back within a working day with a plan you can start now, or a place on file for when retatrutide launches in the UK.
Related pages
What to look at next.
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GLP-1 weight-loss clinic
The umbrella programme for injectable weight loss in the UK.
Learn more -
Wegovy (semaglutide)
The most established licensed option, around 15% mean weight loss.
Learn more -
Saxenda (liraglutide)
Daily injection, older GLP-1 option, still useful for selected cases.
Learn more -
Allurion swallowable balloon
Four-month intragastric balloon, no endoscopy needed to place.
Learn more -
Endoscopic sleeve gastroplasty
Day-case endoscopic gastric reshaping, no incisions.
Learn more -
Obesity condition guide
Background on obesity, comorbidities and the full treatment ladder.
Learn more