Pfizer's danuglipron, an oral GLP-1 receptor agonist developed as a tablet for obesity treatment, has not progressed to Phase 3 trials and is not approved in the UK. In December 2023, Pfizer discontinued the twice-daily formulation due to tolerability issues, and in June 2024, the once-daily version failed to meet efficacy and tolerability targets. Whilst danuglipron is not available, UK patients can access MHRA-approved GLP-1 treatments such as semaglutide (Wegovy) and liraglutide (Saxenda) through NHS specialist weight management services, subject to NICE eligibility criteria and supply availability.
Summary: Pfizer's danuglipron obesity pill has not received UK regulatory approval and is not progressing to Phase 3 trials after failing to meet efficacy and tolerability targets in 2024.
- Danuglipron is an oral GLP-1 receptor agonist that was designed as a tablet alternative to injectable weight-loss medications.
- Pfizer discontinued the twice-daily formulation in December 2023 due to gastrointestinal side effects and high discontinuation rates.
- The once-daily modified-release version did not meet development targets and was halted in June 2024.
- Currently approved GLP-1 treatments in the UK include injectable semaglutide (Wegovy) and liraglutide (Saxenda), available through specialist NHS services.
- NICE recommends GLP-1 therapies for adults with BMI ≥35 kg/m² or BMI 30–34.9 kg/m² with weight-related comorbidities, limited to 2 years' treatment.
- Patients seeking obesity treatment should consult their GP for assessment and potential referral to specialist weight management services.
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What Is Pfizer's Obesity Treatment Pill?
Pfizer has been developing danuglipron, an oral glucagon-like peptide-1 (GLP-1) receptor agonist designed for weight management and type 2 diabetes treatment. Unlike existing injectable GLP-1 medications such as semaglutide (Wegovy) and liraglutide (Saxenda), danuglipron was formulated as a tablet, offering a potentially more convenient alternative for patients who prefer oral medication.
The drug works by mimicking the action of naturally occurring GLP-1 hormones in the body. GLP-1 receptor agonists function through multiple mechanisms: they slow gastric emptying, which prolongs feelings of fullness after eating; they reduce appetite by acting on brain centres that regulate hunger; and they improve glucose-dependent insulin secretion whilst suppressing glucagon release. These combined effects lead to reduced caloric intake and subsequent weight loss.
Development status: Pfizer's development programme for danuglipron has encountered significant challenges. In December 2023, the company discontinued the twice-daily immediate-release formulation for obesity due to tolerability issues, primarily gastrointestinal side effects. In June 2024, Pfizer announced that the once-daily modified-release formulation did not meet efficacy and tolerability targets and would not progress to Phase 3 trials for obesity. As of early 2025, danuglipron has not received regulatory approval from the Medicines and Healthcare products Regulatory Agency (MHRA) or the European Medicines Agency (EMA).
It is important to note that danuglipron is not currently available for prescription in the UK. Healthcare professionals and patients should rely on established, MHRA-approved treatments for obesity management. Patients should not attempt to access unapproved medications through unregulated sources, as this poses significant safety risks.
Who Can Use GLP-1 Obesity Treatments in the UK?
Since danuglipron has not received MHRA approval and is not progressing to Phase 3 trials, there are no prescribing criteria for this medication in the UK. Any future use would depend on regulatory authorisation and subsequent NICE technology appraisal.
For currently approved GLP-1 receptor agonists available for weight management in the UK, NICE has established specific eligibility criteria:
Semaglutide (Wegovy) – NICE TA875 recommends semaglutide for adults with:
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A body mass index (BMI) of 35 kg/m² or above with at least one weight-related comorbidity (such as hypertension, dyslipidaemia, obstructive sleep apnoea, or cardiovascular disease), or
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A BMI of 30–34.9 kg/m² with at least one weight-related comorbidity, prescribed only in specialist weight management services
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Evidence of previous unsuccessful weight loss attempts through diet, physical activity, and behavioural interventions
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Treatment is limited to a maximum of 2 years
Liraglutide (Saxenda) – NICE TA664 recommends liraglutide for adults with:
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A BMI of 35 kg/m² or above (with or without comorbidities), or
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A BMI of 30–34.9 kg/m² with at least one weight-related comorbidity
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Evidence of previous unsuccessful weight loss attempts
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Treatment is limited to a maximum of 2 years
Both medications must be prescribed as part of a specialist weight management service providing multidisciplinary support, including dietary advice, physical activity programmes, and behavioural interventions. Treatment should be discontinued if patients do not achieve at least 5% weight loss after 6 months (semaglutide) or 12 weeks (liraglutide).
Contraindications and precautions for GLP-1 receptor agonists, as detailed in UK Summaries of Product Characteristics (SmPCs), include:
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Contraindications: Pregnancy; hypersensitivity to the active substance or excipients
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Warnings and precautions: Personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia syndrome type 2; history of pancreatitis; severe gastrointestinal disease (including gastroparesis); diabetic retinopathy (for semaglutide in diabetes); renal impairment
Patients who are breastfeeding should discuss risks and benefits with their healthcare provider, as data are limited. Women of childbearing potential should use effective contraception during treatment.
Prescribing decisions must be made by qualified healthcare professionals following comprehensive assessment, including evaluation of cardiovascular risk factors, renal function, and potential drug interactions.
Clinical Trial Results for Danuglipron
Pfizer conducted Phase 2 clinical trials of danuglipron, which provided preliminary evidence of weight loss efficacy but also revealed significant tolerability challenges that ultimately halted the obesity development programme.
In Phase 2a studies evaluating the twice-daily immediate-release formulation, participants achieved modest weight reduction compared to placebo. However, the trials were notable for high discontinuation rates, primarily due to gastrointestinal adverse effects including nausea, vomiting, and diarrhoea. These tolerability issues prompted Pfizer to develop a modified-release formulation designed to reduce side effects whilst maintaining therapeutic efficacy.
Topline results from the twice-daily immediate-release formulation (announced December 2023) showed weight loss of approximately 8–13% over 32 weeks at higher doses, but with substantial discontinuation rates due to gastrointestinal side effects. Based on these findings, Pfizer discontinued the twice-daily formulation for obesity.
The once-daily modified-release formulation was subsequently evaluated in Phase 2 trials. In June 2024, Pfizer announced that this formulation did not meet the company's efficacy and tolerability targets and would not progress to Phase 3 trials for obesity. Specific weight loss data for the once-daily formulation have not been fully disclosed in peer-reviewed publications.
For context, injectable semaglutide (Wegovy) has demonstrated average weight loss of approximately 15% in pivotal trials, whilst liraglutide (Saxenda) achieves around 8% weight reduction over 56–68 weeks.
It is important to emphasise that Phase 2 results are exploratory and involve smaller patient populations than Phase 3 trials. Key questions that remain unanswered for danuglipron include:
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Long-term weight maintenance beyond one year
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Cardiovascular outcomes and mortality benefits
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Comparative effectiveness against established injectable GLP-1 therapies
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Real-world adherence rates and tolerability in broader populations
Patients and healthcare professionals should await peer-reviewed publication of complete trial data before drawing definitive conclusions about danuglipron's clinical utility. There is currently no evidence supporting its use outside of clinical trial settings, and the obesity development programme is not progressing to Phase 3.
Side Effects and Safety Considerations
Based on clinical trial data for danuglipron and the established safety profile of the GLP-1 receptor agonist class, several adverse effects and safety considerations are relevant.
Gastrointestinal side effects have been the most prominent concern in danuglipron trials and are common across the GLP-1 class. Frequently reported adverse effects include:
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Nausea (affecting a significant proportion of participants)
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Vomiting
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Diarrhoea
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Abdominal pain and discomfort
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Constipation
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Dyspepsia
These effects are typically most pronounced during treatment initiation and dose escalation. The high discontinuation rate in danuglipron trials was primarily due to gastrointestinal tolerability issues. Patients prescribed GLP-1 therapies are generally advised to eat smaller, more frequent meals and avoid high-fat foods to minimise gastrointestinal symptoms.
Serious adverse effects and risks associated with the GLP-1 class, as detailed in UK Summaries of Product Characteristics, include:
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Pancreatitis: Patients should be counselled to stop treatment and seek immediate medical attention if they experience severe, persistent abdominal pain radiating to the back, with or without vomiting
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Gallbladder disease: Rapid weight loss can increase the risk of cholelithiasis and cholecystitis. Patients should seek medical advice if they develop symptoms such as sustained pain in the upper right abdomen, fever, or jaundice
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Hypoglycaemia: Risk is increased when GLP-1 receptor agonists are used alongside insulin or sulfonylureas in patients with type 2 diabetes. Blood glucose monitoring should be intensified when initiating treatment
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Acute kidney injury: Usually secondary to severe dehydration from vomiting and diarrhoea; maintaining adequate hydration is essential
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Thyroid C-cell tumours: GLP-1 receptor agonists have been associated with thyroid C-cell tumours in rodent studies. The relevance to humans is unknown. Patients with a personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia syndrome type 2 should be counselled about this risk
Patient safety advice for those using GLP-1 receptor agonists includes:
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Report persistent nausea, vomiting, or abdominal pain to your GP promptly
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Stop treatment and seek urgent medical care if you develop severe, persistent abdominal pain that may suggest pancreatitis
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Maintain adequate hydration, especially during initial treatment and if experiencing vomiting or diarrhoea
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Monitor for signs of gallbladder problems (sustained upper right abdominal pain, fever, jaundice)
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Patients with diabetes should monitor blood glucose levels closely, particularly when starting treatment or adjusting doses
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Inform healthcare providers of all medications to assess interaction risks
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Report suspected side effects via the MHRA Yellow Card scheme at yellowcard.mhra.gov.uk or through the Yellow Card app
Pregnant women or those planning pregnancy should not use GLP-1 receptor agonists. Weight loss during pregnancy is not recommended, and animal studies have shown potential foetal risks. Women of childbearing potential should use effective contraception during treatment.
Accessing Obesity Treatment Through the NHS
As danuglipron is not approved in the UK and is not progressing to Phase 3 trials, patients seeking obesity treatment must rely on currently available NHS services and MHRA-approved medications.
NHS obesity services follow a tiered approach as outlined in NICE guidance:
Tier 1: Universal services include GP consultations, practice nurse support, and signposting to community weight management programmes. These focus on dietary modification, increased physical activity, and behavioural change strategies.
Tier 2: Lifestyle interventions comprise structured weight management programmes, typically 12-week courses delivered by trained practitioners. These may be available through GP referral or self-referral depending on local commissioning.
Tier 3: Specialist weight management services provide multidisciplinary assessment and intervention for patients with complex obesity, including those with multiple comorbidities or previous unsuccessful weight loss attempts. Access varies by region due to inconsistent commissioning. GLP-1 receptor agonists for weight management must be prescribed through Tier 3 services.
Tier 4: Bariatric surgery is considered for patients with BMI ≥40 kg/m² (or ≥35 kg/m² with comorbidities) who have not achieved adequate weight loss through non-surgical methods, as per NICE guidance.
Currently approved pharmacological treatments available in the UK include:
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Orlistat: A lipase inhibitor that reduces fat absorption; available over-the-counter or on prescription
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Liraglutide (Saxenda): A once-daily injectable GLP-1 receptor agonist, recommended by NICE (TA664) for use in specialist weight management services for a maximum of 2 years
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Semaglutide (Wegovy): A once-weekly injectable GLP-1 receptor agonist, recommended by NICE (TA875) for use in specialist weight management services for a maximum of 2 years
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Naltrexone/bupropion (Mysimba): Licensed in the UK but not routinely recommended by NICE for NHS use
Patients interested in obesity treatment should contact their GP for initial assessment. The GP will calculate BMI, assess comorbidities, review previous weight loss attempts, and discuss appropriate interventions. Referral to specialist Tier 3 services may be arranged if indicated and if local services are available.
It is important to note that access to GLP-1 receptor agonists like semaglutide and liraglutide on the NHS is determined by NICE eligibility criteria (TA875 and TA664) and is subject to specialist service availability and ongoing supply constraints. Treatment is limited to a maximum of 2 years and must be discontinued if adequate weight loss is not achieved within specified timeframes.
Patients should have realistic expectations and be prepared to engage with lifestyle interventions as the foundation of obesity management. Private prescription options exist but involve significant out-of-pocket costs.
Patients must avoid purchasing medications from unregulated online sources, as these may be counterfeit, contaminated, or inappropriately stored, posing serious health risks.
Frequently Asked Questions
Is Pfizer's obesity pill available in the UK yet?
No, Pfizer's danuglipron obesity pill is not available in the UK and has not received MHRA approval. In June 2024, Pfizer announced that the once-daily formulation did not meet efficacy and tolerability targets and would not progress to Phase 3 trials for obesity treatment.
Why did Pfizer stop developing the danuglipron weight loss tablet?
Pfizer discontinued danuglipron development due to significant tolerability issues, primarily gastrointestinal side effects such as nausea, vomiting, and diarrhoea that led to high discontinuation rates. The once-daily modified-release formulation also failed to meet the company's efficacy and tolerability targets in Phase 2 trials.
What GLP-1 obesity treatments can I get on the NHS instead of Pfizer's pill?
The NHS offers injectable GLP-1 treatments including semaglutide (Wegovy) and liraglutide (Saxenda) through specialist weight management services. These are recommended by NICE for adults with BMI ≥35 kg/m² or BMI 30–34.9 kg/m² with weight-related comorbidities, limited to a maximum of 2 years' treatment.
How do I get a prescription for weight loss medication like semaglutide?
Contact your GP for an initial assessment including BMI calculation, comorbidity review, and discussion of previous weight loss attempts. If you meet NICE eligibility criteria, your GP may refer you to a specialist Tier 3 weight management service where GLP-1 medications can be prescribed as part of a multidisciplinary programme.
Are oral GLP-1 tablets better than injections for weight loss?
Oral GLP-1 formulations like danuglipron were designed to offer convenience over injections, but development challenges including gastrointestinal side effects have prevented their approval. Currently approved injectable GLP-1 treatments (semaglutide and liraglutide) have established efficacy and safety profiles with proven weight loss outcomes in clinical trials.
What are the main side effects of GLP-1 weight loss medications?
The most common side effects are gastrointestinal, including nausea, vomiting, diarrhoea, and abdominal discomfort, typically most pronounced during treatment initiation. Serious but rare risks include pancreatitis, gallbladder disease, and acute kidney injury secondary to dehydration, requiring patients to report persistent symptoms promptly to their healthcare provider.
The health-related content published on this site is based on credible scientific sources and is periodically reviewed to ensure accuracy and relevance. Although we aim to reflect the most current medical knowledge, the material is meant for general education and awareness only.
The information on this site is not a substitute for professional medical advice. For any health concerns, please speak with a qualified medical professional. By using this information, you acknowledge responsibility for any decisions made and understand we are not liable for any consequences that may result.
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