Written Evidence Submitted by Mr Neil NICE (National Institute for Health and Care Excellence)-FWM0011

Health and social care select committee

Food and weight management

August 2025

NICE is pleased to respond to the committee’s questions about weight loss medications, based on the work we have done regarding GLP-1 receptor agonists, particularly semaglutide (brand name Wegovy) and tirzepatide (brand name Mounjaro).

NICE’s core purpose is to help practitioners and commissioners get the best care to people, fast, while ensuring value for the taxpayer.

We do this by:

• producing useful and usable guidance for health and care practitioners
• providing rigorous, independent assessment of complex evidence for new health technologies
• developing recommendations that focus on what matters most and drive innovation into the hands of health and care practitioners
• encouraging implementation and uptake of best practice to improve outcomes for everyone.

Introduction

Estimates in Frontier Economics: Estimating the full costs of obesity 2023 found that the cost of treating conditions associated with obesity puts a burden on the NHS of £11.4bn per year.

According to the Health Survey for England 2022, around 64% of adults are either overweight or living with obesity in England. Obesity is the second most common cause of preventable death after smoking.

Challenges and opportunities for the NHS and individuals

Opportunities: 

Weight loss medications such as tirzepatide and semaglutide present significant therapeutic opportunities.

These medications work by mimicking natural hormones that regulate appetite and blood sugar, helping patients feel fuller and experience fewer food cravings when combined with diet, physical activity and behavioural support.

Adding tirzepatide to diet and exercise has been shown in clinical trials to be more effective in reducing weight than diet and exercise support alone. Evidence also suggests it is more effective than semaglutide.  

Clinical trial evidence demonstrates substantial weight loss outcomes; tirzepatide studies showed average weight reductions of 16-22.5% over 72 weeks, with over 80-90% of patients achieving clinically meaningful weight loss of at least 5%.

Overweight and obesity is a risk factor for cardiovascular disease. Clinical trials demonstrated a 20% reduction in major adverse cardiovascular events for overweight or obese adults with established cardiovascular disease when treated with semaglutide. One study showed a mean weight loss of 12.6 kg (9.2%) in individuals with class 3 obesity after 6 months of treatment.

The cardiovascular benefits are particularly noteworthy, with semaglutide now approved as the first weight loss drug for preventing cardiovascular events, demonstrating a 20% reduction in major adverse cardiovascular events including heart attacks and strokes in people with established cardiovascular disease and overweight or obesity. NICE is currently evaluating semaglutide for preventing major cardiovascular events in this population [ID6441], with an expected publication date of May 2026.

NICE’s local formulary information on tirzepatide supports the process of adopting this medicine into local formularies by summarising information that local formulary decision-making groups are likely to need.

NICE has also produced a tirzepatide discussion aid for healthcare professionals and patients and a practical guide to using medicines to manage overweight and obesity.

Challenges: 

Even though several weight-loss medicines have been found to be cost-effective, due to the large number of people eligible for treatment the NHS faces several implementation challenges. The clinical trials used by NICE to evaluate weight loss medicines have all included an adjunct diet and exercise intervention; an adjunct reduced-calorie diet and increased physical activity is also specified in the licence indications for all these medicines. So, it is necessary for weight-loss medicines to be prescribed alongside a wraparound service which includes diet and exercise support.

At the time of evaluating tirzepatide in 2024, these services were only available in specialist weight management services. Tirzepatide is currently the only medication that is available for prescribing in primary care settings, but its implementation is phased due to the need to set up the required wraparound care. NHS England is due to announce more details on provision for this.  Over the next 3 years, up to 220,000 people will be eligible for tirzepatide.  Semaglutide and liraglutide are recommended by NICE only within specialist weight management services. These recommendations reflect the evidence submitted to NICE during guidance development. Access to these medicines has varied according to capacity of these services.

Safety considerations require careful management in people taking weight loss medicines. Many people experience gastrointestinal side effects such as nausea, vomiting, diarrhoea and constipation. These are mostly mild to moderate and are more common when doses are being increased to the highest, most effective dose. But this means that doses must be increased at a pace suited to the individual person, which takes health professional time, and not everyone will be able to tolerate higher doses. Less common but serious, potentially fatal side effects include pancreatitis and gallbladder disorders. Although these are uncommon, if more people are taking tirzepatide or semaglutide the total number of cases will rise.

Tirzepatide and semaglutide are not recommended during pregnancy or in people who can become pregnant and who are not using contraception. Tirzepatide could also make oral contraceptives less effective, so other methods are needed when treatment is started and when doses are being increased.

With semaglutide, people usually regain the weight they have lost by about 2 years after stopping it. Around two thirds of the weight lost while on treatment is regained within the first year after stopping treatment. There is no long-term data for what happens to weight after stopping tirzepatide.

NICE has produced a resource impact template and summary report that allows users to build a comprehensive view of resource requirements.

Cost-effectiveness compared to other treatments

NICE's recommendations are based on cost-effectiveness assessments. To date, NICE has recommended the following medicines for the treatment of obesity:

-          orlistat (TA22; 2001, superseded by NICE Guideline CG246)

-          liraglutide (TA664; 2020)

-          semaglutide (TA874; 2023)

-          tirzepatide (TA1026; 2024)

All these medicines have been found to be cost-effective use of NHS resources, but in populations that are narrower than the population that is covered by the marketing authorisation for the medicines. In addition, some medicines are currently only prescribed in specialist weight management services.

The broader economic case centres on obesity costing the NHS £6.5 billion annually, with over 1 million hospital admissions in 2019/2020 where obesity was a factor.

Although the budget impact associated with these medicines is considerable, their use is cost-effective as they have the potential to reduce downstream healthcare costs through preventing obesity-related conditions such as cardiovascular disease and diabetes.

Equitable access to weight management services

Specialist weight management services are not available in every region of the country and there are waiting lists for access to these services. So, access to semaglutide and liraglutide which are only available in these services is inequitable across the country.

NICE has recommended tirzepatide in either primary care or specialist weight management services for people with a body mass index of at least 35 kg/m2 and at least one weight-related illness. However, as this accounts for a very large number of people (around 3.4 million in England), the roll out of tirzepatide has to be carefully managed to help ensure that other health services are not impacted in a disproportionate way. NHS England has published a commissioning guide and is due to publish more information on the provision of wraparound care. Whilst the funding variation sets a maximum of 12 years, we know that health services are evolving all the time. Therefore, NICE has taken the unprecedented decision to carry out a further review of the tirzepatide roll out after 3 years, 2025 - 28. This will enable the NHS to collect evidence and provide further advice on how the continued roll out of this medicine can be managed using the learning gained from the initial phase. This will help ensure it reaches everyone who is eligible in a safe and effective way.

So, over the 3 years 2025 – 28 around 220,000 people who have the highest clinical need will be offered it, alongside a reduced-calorie diet and increased physical activity.

The high cost of these medications and variation in service provision and capacity may create differential access patterns depending on local commissioning decisions and budget pressures.

NICE acknowledges the challenge of equitable care in our overweight and obesity toolkit which includes resource links, a case study about improving access to weight loss medications in people with learning difficulties and providing equitable diet and exercise support.

Necessary changes and government support

Workforce development: Healthcare professionals require training on the safe prescribing and monitoring of these medications, particularly around managing side effects and identifying patients at risk of serious complications.

Integrated care pathways: Services need to provide comprehensive support combining medication with diet, physical activity, behavioural interventions and managing associated comorbidities as the medications are only effective when used as part of holistic treatment approaches.

Safety infrastructure: Robust systems for monitoring and managing side effects are essential, particularly given the MHRA's concerns about misuse and the serious nature of some reported adverse reactions.

Long-term commissioning: Sustainable funding arrangements are needed beyond pilot programmes, with clear pathways for accessing treatment that don't create artificial barriers based on hospital capacity constraints.

The government's broader approach to obesity outlined in the 10 Year Health Plan, including measures like calorie labelling and working with supermarkets, provides important context for ensuring pharmaceutical interventions are part of comprehensive population health approaches rather than standalone solutions.

Appendix 1

We know that tirzepatide and drugs like it are not suitable for everyone. Therefore, NICE has also released its guideline offering other options to help people living with overweight and obesity. It includes evidence-based recommendations on the prevention and management of overweight, obesity and central adiposity in children, young people and adults. It brings together and updates all of NICE's previous guidelines on overweight and obesity.

Appendix 2

Tirzepatide - a new chapter in obesity treatment | NICE

NICE describes how weight loss drug tirzepatide will be rolled out | NICE

https://www.nice.org.uk/news/articles/annual-bmi-checks-recommended-for-adults-with-long-term-conditions