Can you get weight loss injections at BMI 25?

Where the licensed thresholds come from, and why BMI 25 is outside them

The MHRA sets licensing thresholds based on the populations studied in clinical trials and the benefit-risk balance demonstrated in those populations. SURMOUNT-1, the pivotal trial for tirzepatide (Mounjaro), enrolled adults with a BMI of 30 or above, or 27 and above with at least one weight-related condition. The SURMOUNT-1 results, published in the New England Journal of Medicine, showed average body-weight reductions of around 20–21% at the highest dose over 72 weeks, but crucially, almost nobody in that trial had a BMI of 25.

That is not a bureaucratic quirk. The evidence regulators rely on to confirm that a treatment's benefits outweigh its risks simply does not extend to people at BMI 25. Setting the threshold higher than the trial population would mean approving a medicine for a group it was never tested in. Until trials produce data at that level, the licensed indications stay where they are. NICE's appraisal of tirzepatide under TA1026 reflects the same logic: recommendations follow the evidence base, not the full range of people who might wish to use the medicine.

None of this means a BMI of 25 is unhealthy or that you have no options. It means the current licensed medicines were not designed or tested for people at that weight, and legitimate prescribers won't bypass that boundary.

The gap between 'overweight' on a chart and 'eligible for treatment'

A BMI of 25 is the point at which UK clinical definitions shift from 'healthy weight' to 'overweight'. It feels like a meaningful line, and it is, but it is a different line from the one that unlocks a prescription. The NHS uses BMI alongside other measures such as waist circumference, ethnicity-adjusted thresholds, and clinical risk factors, which is why understanding how BMI is actually used in weight management decisions is more useful than tracking a single number.

Someone with a BMI of 27 who also has hypertension or prediabetes has a clinical case for treatment. Someone at 25 with no weight-related conditions does not, under current evidence or licensing. There is a real frustration in that for people who feel the extra weight acutely but whose BMI falls just short, and that feeling is completely understandable. The honest position, though, is that prescribing outside licensed parameters without robust evidence carries genuine risk, and no responsible prescriber will do it.

If you are uncertain whether any conditions you have might affect your eligibility, the question of which BMI actually qualifies is answered in detail elsewhere, including the lower thresholds that apply for some ethnic backgrounds under UK guidance.

What happens at BMI 27, and why that threshold is different

The 27-with-a-condition threshold is not a workaround. It reflects a genuine clinical rationale: weight-related conditions such as obstructive sleep apnoea, cardiovascular disease, dyslipidaemia, type 2 diabetes, and high blood pressure carry health risks that can be reduced by weight loss, and the benefit-risk calculation tips in favour of treatment even at lower BMI when those conditions are present. The trial populations included people in that range, so the evidence supports the prescribing.

If your BMI is 27 or above alongside a qualifying condition, the route into treatment is a clinical assessment. Eligibility at BMI 27 is examined in full on a dedicated page. For those exploring what the injections currently licensed in the UK actually are, a look at the 3 weight loss injections available in the UK gives a grounded starting point.

At a BMI of 25, the most evidence-supported options remain lifestyle-based: dietary change, physical activity, and addressing any underlying factors driving weight gain. The NHS Live Well healthy weight guidance sets out what that can look like in practice. If circumstances change (a new diagnosis, a shift in BMI) a clinical review becomes worth having, and if you want to understand more about how weight loss injections work and who they are designed for, that context can help you make sense of where you currently stand. Our prescribers are happy to talk through where you stand; a free consultation changes nothing if you are not eligible, but it does give you a clear answer. Start your free consultation here.