Mounjaro Isn't Just a Weight Loss Jab — Here's What Else It Does

What tirzepatide is actually licensed for in the UK — and where the research on sleep apnoea, heart and kidney health is heading.

Part of the Overweight and Obesity Guide.

Ask most people what Mounjaro is for and you'll get the same answer: losing weight. Fair enough — the results speak for themselves, and it's the reason the medicine rarely leaves the headlines.

But Mounjaro wasn't invented as a weight loss drug. Eli Lilly developed tirzepatide — the active ingredient — as a diabetes treatment, and that's still one of its most important jobs. Meanwhile, researchers keep finding that people taking it seem to get healthier in ways that go beyond the number on the scales: better sleep, stronger hearts, kidneys that hold up longer.

So what does Mounjaro actually do, beyond weight loss? And which of those uses are genuinely available in the UK?

Why one medicine does so many things

The reason Mounjaro reaches beyond weight loss comes down to how it works: it acts on two of the body's own gut hormones, GLP-1 and GIP, rather than one. Those hormones don't only govern appetite — they also influence blood sugar, the heart and the blood vessels, which is why the medicine's effects ripple out across several conditions.

We won't rehash the biology here — our dedicated guide on how Mounjaro works covers the dual GIP/GLP-1 mechanism in full, and what is Mounjaro? is the place to start if you're completely new to it. This article is about where those effects lead: the conditions Mounjaro treats, and the ones researchers are still investigating.

Type 2 diabetes: the job Mounjaro was built for

Mounjaro's first MHRA licence, granted back in 2022, was for type 2 diabetes — the weight management licence didn't follow until a year later.

In type 2 diabetes, the body stops responding properly to insulin, and blood sugar creeps up. Left uncontrolled, that excess sugar quietly damages blood vessels, nerves, eyes and kidneys over years. Because Mounjaro boosts insulin exactly when blood sugar is high (rather than all the time), it brings glucose down with a low risk of hypos when used on its own.

The trial data here is hard to argue with. Across the SURPASS programme, tirzepatide lowered HbA1c — the standard three-month measure of blood sugar control — by more than almost every treatment it was tested against, including semaglutide, the active ingredient in Ozempic. A striking number of participants got their HbA1c back into the non-diabetic range.

On the NHS, tirzepatide for diabetes is reserved for people whose diabetes isn't controlled after triple therapy — metformin plus two other oral medicines — and who meet NICE's BMI and clinical criteria. That's a fairly late stage in the treatment pathway, which is why plenty of patients with diabetes first encounter Mounjaro through weight management services instead.

And the two uses feed each other. Excess weight is one of the main drivers of insulin resistance, so as the weight comes off, blood sugar control improves too. For someone living with both obesity and type 2 diabetes, one medicine is working on both problems at once.

Can Mounjaro treat sleep apnoea?

This is the question we're asked most often after diabetes, and the honest answer is: not officially in the UK — but the evidence is compelling.

Obstructive sleep apnoea (OSA) happens when the airway repeatedly narrows or collapses during sleep. The result is loud snoring, gasping awake, and the kind of daytime exhaustion that no amount of coffee fixes. Excess weight around the neck and airway is the biggest single cause.

In the SURMOUNT-OSA trial, adults with obesity and moderate-to-severe OSA who took tirzepatide had roughly 25–30 fewer breathing interruptions per hour of sleep — a dramatic improvement, alongside body weight loss of around 18–20%. On the back of those results, US regulators approved tirzepatide (sold there as Zepbound) for sleep apnoea in December 2024, making it the first medicine ever licensed for the condition.

The MHRA hasn't followed suit, so Mounjaro can't be prescribed for sleep apnoea here. What UK licensing does allow is for OSA to count as a qualifying weight-related condition when Mounjaro is prescribed for weight management. In practice, that distinction matters less to patients than it does to regulators — lose the weight, and for many people the apnoea improves with it.

What about your heart and kidneys?

Some of the most interesting tirzepatide research of the last two years has nothing to do with weight or blood sugar directly.

Take heart failure with preserved ejection fraction (HFpEF) — a common form of heart failure, strongly linked to obesity, with very few effective treatments. In the SUMMIT trial, presented at the American College of Cardiology in 2025, tirzepatide cut worsening heart failure events and left patients able to do noticeably more physically.

Kidney findings are heading the same way. In people with obesity, diabetes and heart disease — the groups most likely to develop chronic kidney disease — trial data suggest tirzepatide slows the decline in kidney function. Separate analyses have also linked it with fewer major cardiovascular events, and dedicated outcome trials are still running.

Researchers are also running early studies in polycystic ovary syndrome (PCOS), where insulin resistance drives many symptoms, and in fatty liver disease (MASLD), where tirzepatide has shown encouraging effects on liver fat. Both are years away from any licence, if they get there at all.

So who can actually get Mounjaro in the UK?

Two groups, matching its two licences:

Qualifying weight-related conditions include:

• High blood pressure
• High cholesterol
• Type 2 diabetes
• Obstructive sleep apnoea

NHS access is tighter than the licence in both cases, which is why many people go through a regulated online pharmacy instead. At Access Doctor, that starts with an online consultation reviewed by a prescriber, who checks the treatment is safe and suitable before anything is dispensed.

A quick word on tolerability: nausea and other digestive symptoms are common, especially in the first weeks and after dose increases. Most people find they settle, but read our guide to Mounjaro side effects before you start so you know what's normal and what isn't.

And if you're weighing Mounjaro against the alternatives, we've compared it directly with Saxenda in Mounjaro vs Saxenda, explained what liraglutide is, and rounded up every option in our UK guide to prescription weight loss medication. Whichever route you take, medication works best alongside the basics — our weight management tips for busy adults covers those.

The bottom line

Mounjaro earned its reputation through weight loss, but calling it a weight loss jab undersells it. It's a proven diabetes treatment, the first medicine ever approved for sleep apnoea anywhere in the world, and the subject of heart and kidney research that keeps surprising cardiologists. In the UK its licensed uses remain diabetes and weight management — but for the patients who qualify, the benefits may not stop there.

Think it could be right for you? Start a confidential online consultation with Access Doctor and one of our prescribers will take it from there.

Mounjaro is available from Access Doctor following an online consultation reviewed by a prescriber, with treatment dispensed from our GPhC-registered pharmacy and delivered in temperature-controlled packaging.