I'm overweight but not obese — should I consider GLP-1 treatment?

You're not in the obese range. You probably don't feel like your weight is a medical emergency. But you've put on a couple of stone in the last few years, you've tried to shift it through diet and exercise, and you've read enough about Mounjaro and Wegovy to wonder whether they might help.

That's a reasonable question. The answer is more nuanced than most content in this space will tell you — and the commercial incentives all point in one direction, which is towards telling you to start.

This article tries to give you the other side of that conversation.

What BMI 27–30 actually means clinically

BMI is an imperfect tool — it doesn't distinguish between muscle and fat, varies with age and ethnicity, and misclassifies a meaningful proportion of people in both directions. With that caveat acknowledged, here's what the bands represent:

At BMI 27–30 without a comorbidity, you're in a zone where treatment is available but the risk-benefit calculation is genuinely less clear-cut than for people with obesity. The medications work — but the question is whether they're the right tool for your situation.

Licensed vs off-label: the real distinction

Off-label prescribing means a clinician is using a licensed medication outside the conditions its licence covers. It's legal, common, and not inherently unsafe — it happens routinely across medicine when a prescriber judges that the evidence supports use in a particular patient.

What it does mean is that:

• The medication's licence was granted based on trials in people with obesity (BMI 30+) or overweight with comorbidities (BMI 27+). The evidence base for your specific situation — overweight without comorbidities — is thinner
• A responsible prescriber should explicitly discuss that you're being prescribed off-label, explain what that means, and document that you've understood and consented to it
• If you experience side effects, the same reporting and support pathways apply — but you should be aware the risk-benefit profile was modelled on a different population

The case for treatment at lower BMI

There is a genuine clinical argument for early intervention — and it's worth taking seriously rather than dismissing.

The trajectory argument

Weight tends to accumulate gradually over years. A BMI of 28 today is often a BMI of 32 in five years without intervention — particularly in mid-life when basal metabolic rate declines, activity levels typically fall, and dietary patterns are harder to change. Treating earlier, when the health risks are lower and the weight to lose is less, is more straightforward than treating later.

Metabolic risk appears before BMI hits 30

BMI is a blunt instrument. Visceral fat — the metabolically active fat around the organs — begins accumulating and creating cardiovascular and metabolic risk at lower BMI levels, particularly in people over 40, post-menopausal women, and people of South Asian, East Asian and African-Caribbean descent who typically carry higher metabolic risk at lower BMI. Some clinicians argue the 30 threshold is biologically arbitrary.

The diabetes prevention evidence

The landmark Diabetes Prevention Program found that losing just 5–7% of body weight — achievable on GLP-1 treatment without necessarily reaching a "normal" BMI — reduced the risk of developing type 2 diabetes by approximately 58% in people with prediabetes. For someone at BMI 28–29 who is heading toward type 2 diabetes, that's a meaningful preventive argument.

Wegovy's cardiovascular indication

Since 2026, Wegovy has a licensed indication for reducing cardiovascular risk in people with established cardiovascular disease at BMI 27 or above. This isn't about weight loss — it's about direct cardiovascular protection. If you have cardiovascular disease, you may be within the licensed criteria even at BMI 27–29.

The honest case against

The argument against treatment at lower BMI is not that the medications don't work — they do. It's about whether the risk-benefit equation stacks up for your specific situation.

The weight regain problem is more significant at lower BMI

A 2026 BMJ meta-analysis found that people who stop GLP-1 treatment return to their baseline weight within an average of 1.7 years. For someone at BMI 32 who loses 20% of their weight, this is a serious health concern. For someone at BMI 28 who loses 15% and then regains it over 18 months, the net result is approximately zero — except for the cost, the time injecting weekly, and the side effects endured during that period.

The side effect burden is the same regardless of BMI

Nausea, constipation, and gastrointestinal side effects affect the majority of people starting these medications. At BMI 35 with type 2 diabetes and high blood pressure, that's a reasonable trade-off for significant health gains. At BMI 28 with no comorbidities, you're accepting the same side effect burden for a more marginal clinical benefit.

The evidence base is thinner

The major trials — SURMOUNT-1, STEP-1, SURMOUNT-5 — were conducted primarily in people with obesity. Real-world data on long-term outcomes in people at BMI 27–30 without comorbidities is limited. "It works in trials of people with obesity" is not the same as "it's clearly beneficial for someone in your situation."

Lifestyle intervention has a stronger relative case

At BMI 28–29, a structured dietary and exercise programme can achieve 5–10% weight loss — enough to produce meaningful metabolic benefit — without the cost, indefinite commitment, or side effects of medication. The evidence base for lifestyle intervention at this BMI is actually quite strong. It requires more willpower and consistency, but it also leaves you in a better position when you stop, since the metabolic adaptation is more durable than after medication cessation.

The cost-benefit question nobody does for you

Let's be concrete. At BMI 28, a typical scenario might look like this:

That ongoing cost is the number most people don't look at clearly before starting. If you maintain the medication for five years to keep the weight off, you're looking at £9,000–£18,000 over that period. The question is whether that's a reasonable investment for the health benefit at your starting BMI.

For some people — particularly those with strong family history of type 2 diabetes, significant visceral fat, or early metabolic markers — the answer may well be yes. For others — particularly younger people at the lower end of this BMI range with no risk factors — the calculus is much harder to justify.

Who it makes most sense for

Questions to ask your prescriber

If you decide to have a consultation about treatment at this BMI, these are the questions worth asking explicitly. A good prescriber will engage with all of them. Evasiveness is a signal.

• Is this prescription within the licensed criteria, or is it off-label? If off-label, what is your clinical justification for prescribing in my specific situation?
• What is my actual metabolic risk profile? Not just my BMI — what do my blood glucose, triglycerides, blood pressure, and waist circumference tell you about whether I would benefit?
• Have you considered lifestyle intervention as a first step? If so, why do you think medication is more appropriate for me?
• What does long-term treatment look like? Am I starting something I'll need to maintain indefinitely, and what's the plan if I want to stop?
• What would you expect to see at 3 months that would confirm I'm responding appropriately?
• What is your policy on stopping treatment if I'm not achieving the expected response, or if I decide the medication isn't right for me?

Other reasons people are being prescribed these medications

Weight loss is the most visible use case, but GLP-1 medications are increasingly being used — and in some cases actively trialled — for a range of conditions beyond BMI-based obesity. This matters for people at lower BMI because it broadens the clinical justification for treatment beyond weight alone.

MASH (metabolic dysfunction-associated steatohepatitis)

MASH — the progressive, inflammatory form of fatty liver disease — affects a significant proportion of people who are overweight or obese, often without symptoms until the disease is advanced. It is one of the fastest-growing causes of liver transplant need in the UK.

The evidence for GLP-1 medications in MASH is now substantial. A phase 2 NEJM trial found that tirzepatide produced resolution of MASH without worsening fibrosis in 44–62% of patients depending on dose, compared to 10% on placebo — across all three doses tested. A phase 3 trial of semaglutide in MASH (the ESSENCE study) is currently running and published interim results in 2025 showing meaningful histological improvement.

Sleep apnoea

Tirzepatide has demonstrated significant reduction in apnoea-hypopnoea index in patients with moderate-to-severe obstructive sleep apnoea in the SURMOUNT-OSA trial. This isn't just an effect of weight loss — there appears to be a direct mechanism. Sleep apnoea is common in people who are overweight but not technically obese, and is a recognised comorbidity that places you within the licensed criteria at BMI 27+.

Cardiovascular risk reduction

Wegovy has a licensed indication for reducing major cardiovascular events in people with established cardiovascular disease at BMI 27+. This is not about weight loss — it's a direct cardiovascular effect confirmed in the SELECT trial. If you have a history of heart attack, stroke, or established coronary artery disease, you are within the licensed criteria at BMI 27 regardless of whether you have a weight-related comorbidity in the conventional sense.

Polycystic ovary syndrome (PCOS)

GLP-1 medications are increasingly used off-label for PCOS management — the combination of insulin resistance improvement, weight loss, and hormonal effects makes them clinically relevant for women with PCOS even at lower BMI. This is not yet a licensed indication but is actively studied and increasingly common in clinical practice.

Type 2 diabetes prevention

For people with prediabetes — impaired fasting glucose or impaired glucose tolerance — GLP-1 treatment is not licensed for prevention, but the Diabetes Prevention Program evidence (58% reduction in progression to type 2 diabetes with 5–7% weight loss) provides a strong off-label argument. Some prescribers will treat prediabetes as a qualifying comorbidity at BMI 27+; others won't. Ask explicitly.

Common questions