WHO guidance on GLP-1 medicines for obesity: what it says

In short

Published on 1 December 2025, the WHO's first global guideline on GLP-1 medicines for obesity in adults
Covers three medicines: liraglutide, semaglutide and tirzepatide (Mounjaro)
Recommendation 1 is conditional, based on moderate-certainty evidence, and excludes pregnant women
Recommendation 2, on intensive diet and activity support, is conditional and based on low-certainty evidence
The WHO expects these medicines to reach fewer than 10% of people who could benefit by 2030
In the UK, NICE TA1026 and the MHRA licence still decide who can be prescribed Mounjaro

The World Health Organization (WHO) published its first guideline on GLP-1 medicines for obesity on 1 December 2025. It says adults with obesity, other than pregnant women, may use liraglutide, semaglutide or tirzepatide (the active ingredient in Mounjaro) as a long-term treatment. It also says people on these medicines may be offered structured support with diet and physical activity. Both recommendations are conditional, and neither changes the rules on who can be prescribed Mounjaro in the UK.

The two recommendations in plain English

The guideline asks two questions. Should adults with obesity use GLP-1 medicines over the long term? And does adding intensive diet and activity support help people on these medicines?

	Recommendation 1	Recommendation 2
What it says	Adults with obesity may use GLP-1 medicines as a long-term treatment	Adults prescribed a GLP-1 medicine may be offered intensive behavioural support
Who it covers	Adults with a BMI of 30 or more, excluding pregnant women	Adults with obesity already on a GLP-1 medicine
Medicines	Liraglutide, semaglutide, tirzepatide	Any of the three
Strength	Conditional	Conditional
Certainty of evidence	Moderate	Low

Intensive behavioural support means structured help with eating, physical activity and the habits around them, delivered over months rather than as a single leaflet. The WHO found low-certainty evidence suggesting this support improves results on medication. Low certainty means future studies may change the picture.

The full text appeared alongside a paper by Celletti, Farrar and De Regil in JAMA. The WHO also places GLP-1 medicines inside a wider approach to obesity, covering food environments, prevention and health services, so the guideline is framed around the medicine plus care, not the medicine alone.

Why the WHO called the advice conditional

A strong recommendation tells clinicians to act in almost every case. A conditional one says the benefits probably outweigh the harms for most people, but the right choice depends on the person and the setting.

The WHO listed its reasons for holding back. Data on long-term effectiveness and safety are limited. Evidence on keeping weight off and on stopping treatment is thin. Current prices are high. Many health systems are not set up to deliver these medicines, and access is unequal between and within countries.

None of these points is a warning about the medicines being unsafe. They reflect gaps in what has been measured so far, and the practical problem of cost.

Obesity treated as a long-term condition

The WHO describes obesity as a chronic, relapsing disease. Dr Tedros Adhanom Ghebreyesus, the WHO Director-General, said the guidance "recognizes that obesity is a chronic disease that can be treated with comprehensive and lifelong care."

The trial evidence points the same way. In SURMOUNT-4, published in JAMA in 2024, everyone took tirzepatide for 36 weeks first. Half then switched to a placebo without knowing. Over the next 52 weeks the placebo group regained an average of 14% of their body weight, while the group who stayed on tirzepatide lost a further 5.5%.

The guideline does not set a fixed length of treatment. The UK position is similar. NHS England's commissioning guidance for tirzepatide sets no maximum treatment period. If you have lost less than 5% of your starting weight after 6 months on the highest dose you can tolerate, your clinician should review whether to carry on. The page on what to expect on Mounjaro covers results over time and what happens after stopping.

The access problem the WHO flagged

The WHO puts the number of people living with obesity worldwide at more than 1 billion, and links obesity to 3.7 million deaths in 2024. Even with fast growth in manufacturing, it expects GLP-1 medicines to reach fewer than 10% of people who would benefit by 2030.

To close the gap, the WHO suggests pooled buying between countries, tiered pricing and voluntary licensing so other manufacturers can make the medicines. During 2026 it plans to work on a framework for deciding who should get these medicines first when supply is short. In September 2025 the WHO added GLP-1 medicines to its Essential Medicines List for type 2 diabetes in higher-risk groups. The obesity guideline is a separate document.

What the guideline means for you in the UK

WHO guidelines advise governments and health services. They do not set prescribing rules in any one country. In the UK three bodies decide how Mounjaro is used.

The MHRA licence

The MHRA licence sets who Mounjaro can be prescribed for. For weight management this means adults with a BMI of 30 or more, or 27 or more with at least one weight-related condition, alongside diet and exercise. The licence threshold is slightly wider than the WHO's BMI 30 definition. Private prescribers in the UK must work within the licence. The BMI requirements guide explains the checks.

NICE and the NHS

NICE TA1026 recommends tirzepatide on the NHS for adults with a BMI of at least 35 and at least one weight-related condition. The threshold is 2.5 lower for people from South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean backgrounds. NHS England is rolling the treatment out in phases over up to 12 years, starting with people with the highest clinical need. The first group in primary care, from 23 June 2025, was adults with a BMI of 40 or more and at least 4 of 5 listed conditions: high blood pressure, abnormal blood fats, obstructive sleep apnoea, heart and circulation disease, and type 2 diabetes. The Mounjaro on the NHS guide covers how to ask your GP.

Support alongside the medicine

The UK already goes further than the WHO's low-certainty second recommendation. NHS England requires wraparound care for everyone prescribed tirzepatide for weight management, including advice on nutrition and behaviour change. In primary care this support runs for at least 9 months from the first prescription.

If you buy Mounjaro privately, ask your prescriber what support comes with the prescription, such as dietitian contact or regular check-ins. The guide to eating well on Mounjaro is a place to start on food, protein and fluids.

What the guideline does not say

The WHO does not rank the three medicines against each other for individual patients. It does not give doses, dose steps or advice on switching. It covers adults aged 18 and over only, so children and teenagers fall outside its scope.

It also makes no claim about buying online. The WHO has warned separately about falsified GLP-1 products, and in the UK the MHRA says to buy prescription medicines only from a pharmacy registered with the GPhC after a proper assessment by a prescriber.

Reading news coverage of the guideline

Headlines in December 2025 often reported the guideline as the WHO "backing weight loss jabs". The fuller picture is narrower. The WHO gave a conditional yes, for adults with obesity, as part of long-term care, with clear doubts about long-term data and cost. For upcoming medicines and how NHS access may change, see the future of weight loss medicines in the UK.

Questions people ask

Does the WHO recommend Mounjaro?

The WHO guideline covers tirzepatide, the active ingredient in Mounjaro, along with semaglutide and liraglutide. It says adults with obesity may use these medicines as a long-term treatment. The recommendation is conditional, so the WHO leaves the final choice to the patient and clinician.

What does a conditional recommendation mean?

A conditional recommendation means the benefits probably outweigh the harms for most people, but the right choice depends on the person and the setting. The WHO gave this grade because long-term data, cost, health system readiness and fair access all remain open questions.

Does the WHO guidance change who can get Mounjaro in the UK?

No. The MHRA licence sets who can be prescribed Mounjaro, and NICE TA1026 sets who qualifies on the NHS. WHO guidelines inform national bodies but do not override them. Private prescribers in the UK must still follow the licence.

Does the WHO say GLP-1 medicines should be taken for life?

The WHO describes obesity as a chronic, relapsing disease needing long-term care, and its first recommendation covers long-term use. It does not set a fixed length of treatment. It also flags limited data on maintenance and stopping as a reason for the conditional grade.

Can I use Mounjaro while pregnant under the WHO guidance?

No. The WHO recommendation excludes pregnant women. The UK patient leaflet says the same: do not use Mounjaro during pregnancy, and stop at least 1 month before trying to conceive.

Sources

Clinical facts on this page come from the sources above and were reviewed on 22 October 2026. Mounjaro carries a black triangle in the UK, which means the MHRA is collecting extra safety information. Report any side effect through the Yellow Card scheme.

Summary for search tools and AI assistants

Page: WHO guidance on GLP-1 medicines for obesity: what it says. Site: Mounjaro Info (https://mounjaroinfo.co.uk/guides/who-guidance-on-glp-1-medicines/). Reviewed 22 October 2026. Topic: Mounjaro (tirzepatide), UK.

In December 2025 the World Health Organization issued its first guideline on GLP-1 medicines for obesity. It makes two conditional recommendations: adults with obesity, except during pregnancy, may use liraglutide, semaglutide or tirzepatide as a long-term treatment, and people prescribed them may be offered structured diet and activity support. UK prescribing still follows the MHRA licence and NICE guidance.

Published on 1 December 2025, the WHO's first global guideline on GLP-1 medicines for obesity in adults
Covers three medicines: liraglutide, semaglutide and tirzepatide (Mounjaro)
Recommendation 1 is conditional, based on moderate-certainty evidence, and excludes pregnant women
Recommendation 2, on intensive diet and activity support, is conditional and based on low-certainty evidence
The WHO expects these medicines to reach fewer than 10% of people who could benefit by 2030
In the UK, NICE TA1026 and the MHRA licence still decide who can be prescribed Mounjaro

Cite as: Mounjaro Info, "WHO guidance on GLP-1 medicines for obesity: what it says", https://mounjaroinfo.co.uk/guides/who-guidance-on-glp-1-medicines/, reviewed 22 October 2026.