Mounjaro in the UK: NHS Rules, Private Cost, and Keeping Muscle

Both are tirzepatide, made by Eli Lilly. The brand name changes by country and by what it is licensed for.

Zepbound is not licensed or marketed in the UK. It does not appear in the UK medicines register at all. If a website offers to sell you Zepbound in Britain, that is a reason to stop and check who you are dealing with.

Why this matters for reading anything about muscle: most of the published research uses the American names, because the big trials were run there. The SURMOUNT-1 body-scan findings we cover in does Zepbound cause muscle loss are findings about tirzepatide, so they describe exactly what Mounjaro does in your body.

One UK detail worth knowing: Wegovy now means three different things. The weekly pen up to 2.4 mg, a 7.2 mg single-dose pen approved by the MHRA on 14 April 2026, and a daily tablet approved on 11 June 2026, the first GLP-1 tablet for weight loss in the UK ^[4].

In England, yes in principle, but there is a queue and it is long.

What NICE recommends. Tirzepatide is recommended for people with a BMI of 35 or over plus at least one weight-related condition, alongside a reduced-calorie diet and more physical activity ^[5]. The BMI threshold drops by 2.5 kg/m² for people of South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean background, so 32.5 rather than 35 ^[5].

Unlike Wegovy, tirzepatide can be prescribed in primary care, not only through a specialist weight management service ^[5]. GP prescribing for obesity began on 23 June 2025.

What is actually happening. NHS England is releasing it in cohorts. As at September 2026 the window that opened in June 2026 covers BMI 35 to 39.9 with four or more of: high blood pressure, high cholesterol, obstructive sleep apnoea, cardiovascular disease, or type 2 diabetes. People in the first cohort, BMI 40 or over with four or more conditions, remain eligible ^[6].

Be careful with dates here. NICE's patient-facing page still says "you may be eligible now" next to the BMI 40 criteria and "from around June 2026" next to the 35 to 39.9 group. That wording was written in 2025 and has not been updated. June 2026 has passed.

How long the queue is. NICE expects about 220,000 people to be on tirzepatide through the NHS by 2028, against roughly 3.4 million who meet the criteria, with full access taking up to 12 years from 2025 ^[7]. For scale, London had 3,000 people on NHS weight-loss medicines as of November 2025, with around 500,000 eventually eligible ^[7].

That gap is why most people in Britain who take these drugs pay for them.

It is not the same across the UK

• Scotland is more generous. The Scottish Medicines Consortium accepted tirzepatide for BMI 30 or over with at least one weight-related condition ^[8], a lower bar than England's 35.
• Wales is stricter. Its current circular, updated July 2026, says tirzepatide, semaglutide and liraglutide for weight loss "should only be prescribed through specialist weight management services" ^[9]. There is one narrow exception for prescribers outside those services, limited to defined clinical groups such as people with a precancerous condition, transplant candidates, or idiopathic intracranial hypertension. A Welsh GP cannot put you on it for weight alone.
• Northern Ireland is behind the rest of the UK. We could not confirm a current NHS route or a start date from the Department of Health or the NI Formulary on 19 September 2026, so rather than guess: ask your GP where Northern Ireland has got to. If you find a published position we have missed, tell us and we will correct this.

Prices from three named providers, read from their own pages on 19 September 2026. They change often, so check before you buy.

Why it got more expensive. Eli Lilly raised the UK list price on 1 September 2025, saying it brought Britain in line with Europe. The published NHS list price at the top dose went from £122 to £330 a month, an increase of about 170% ^[5].

A number you will see quoted that is wrong. "The NHS pays £122 a month" is the old list price from before September 2025, not a current NHS price. What the NHS actually pays is confidential under a commercial arrangement, and NICE says so plainly ^[5]. Nobody outside those contracts knows the figure.

How many people are doing this. A nationally representative survey of Great Britain published in BMC Medicine in January 2026 found 2.9% of adults, about 1.6 million people, had used a GLP-1 medicine for weight loss in the past year ^[10]. The fieldwork was early 2025, so today's number is higher. The study did not record how people obtained the medicine, so it does not give a private-versus-NHS split. Set it against the NHS figures above and the direction is obvious: most UK use is private.

We went looking for official UK advice on protein and strength training for people on these medicines. Here is what we found, including the gaps, because the gaps are the point.

NICE says nothing. We searched the full text of NICE's prescribing guide for weight-management medicines and of NG246, the overweight and obesity guideline, on 19 September 2026. Across both, there are zero mentions of protein, muscle, lean mass, resistance training or strength training. The advice is "a reduced-calorie diet and increased physical activity", with a link to the general physical activity guidelines.

The London Assembly's 100-page report on weight-loss medication, published March 2026, contains no occurrence of "muscle", "protein", "lean mass" or "sarcopenia" either.

The British Dietetic Association does say it, and as far as we can find it is the only UK body that does. Its Obesity Specialist Group guide Medications for obesity: a guide to eating and living well, February 2026, says ^[11]:

"Eating less food can help you lose weight, but you can also lose muscle as well as body fat. If you don't eat enough protein or do enough physical activity, you could lose too much muscle. This can make your body weak, which is called sarcopenia. To keep your muscles strong, aim to eat protein with each meal and do some strength activities."

It has a protein section and a section on strength activities with practical examples: resistance bands, chair sit-to-stands, tins of food as weights, building from five minutes to ten.

Two honest caveats about that guide. First, it gives no numbers: no grams per meal, no grams per kilo. Second, its own front matter discloses that Novo Nordisk provided a grant and Eli Lilly provided sponsorship towards producing it. Both companies make the medicines it covers. The BDA states neither had input into the content. We think it is good advice, and you should know who paid for it.

So where do numbers come from? Not from a UK source. The figures we use, 1.2 to 1.5 g of protein per kg of body weight a day, come from a 2025 international expert consensus and a 2025 joint advisory by four American professional bodies ^{[13] [12]}. There is no UK equivalent. Our protein calculator applies those numbers and publishes exactly how.

If you are taking it, privately or on the NHS. The two things with evidence behind them are protein and resistance training, and neither costs anything.

1. Work out your protein range with the protein calculator, then split it across meals. Appetite is the constraint, not willpower.
2. Start lifting twice a week. Our 12-week plan is built for people who have not trained in years and works at home.
3. Check something real every few weeks. A chair-stand test or grip test tells you more about function than the scale does.
4. If you want an idea of the fat and lean split of what you have already lost, the muscle loss calculator gives you the range from 36 trials ^[14].

If you are waiting for the NHS. The queue is measured in years, not months. Everything above works without the medicine, and the muscle you keep now is muscle you do not have to rebuild later. Our guide on losing fat without losing muscle covers the same ground for people not on medication.

A note on what we are. We are not a pharmacy, a prescriber or a UK healthcare provider. We do not sell, supply or arrange any medicine, and nothing here is a recommendation to take one. Prescription medicines in the UK are for your GP or a registered prescriber to discuss with you. This page exists because the nutrition and training side of taking them is barely covered by UK guidance, and that part we do know about.