Weight Loss Injections at BMI 27: Are You Eligible?

Step 1, Understand the licensed threshold at BMI 27

The licences granted by the MHRA for tirzepatide (Mounjaro) and semaglutide (Wegovy) both follow the same basic pattern: adults with a BMI of 30 or above qualify on BMI alone; adults with a BMI between 27 and 29.9 qualify only when at least one weight-related comorbidity is also present. The full picture of how weight loss injections work in the UK covers both medicines in detail, but for BMI 27 the key question is: do you have a qualifying condition?

Conditions that count include type 2 diabetes, prediabetes, hypertension, dyslipidaemia (raised cholesterol or triglycerides), obstructive sleep apnoea and osteoarthritis, among others. One is enough. If you have been told by a GP that any of these apply to you, BMI 27 is likely inside the licensed range. The NHS BMI calculator is a useful starting point if you want to check or confirm your BMI before a consultation.

It is also worth knowing that for people of South Asian, Chinese, Middle Eastern, Black African or African-Caribbean backgrounds, UK guidance typically lowers the threshold by 2.5 kg/m², so effective eligibility can begin closer to BMI 25 for the comorbidity group. If that applies to you, the page on eligibility at BMI 25 explores those adjusted thresholds in more depth.

Step 2, Know which injections are actually licensed at this BMI

Two injectable medicines are currently licensed in the UK for weight management in the 27-plus-comorbidity bracket: tirzepatide, sold as Mounjaro, and semaglutide, sold as Wegovy. They work via different mechanisms (tirzepatide activates both the GIP and GLP-1 gut-hormone receptors, while semaglutide acts on the GLP-1 receptor only) but both reduce appetite and slow gastric emptying, making it easier to eat less without constant hunger.

In clinical trials, both produced meaningful average weight reductions. SURMOUNT-1 recorded around 20–21% average weight loss at the highest tirzepatide dose over 72 weeks, while STEP 1 recorded around 15% with semaglutide 2.4mg over 68 weeks, as published in the New England Journal of Medicine. Comparing them directly is easier on the guide to the main licensed injection options, which sets out the evidence side by side.

Neither medicine is available without a prescription. Sellers offering them otherwise are operating outside UK law and, in many cases, supplying counterfeit or unverified products. The MHRA has warned publicly about fake weight-loss pens seized in large quantities from illegal UK supply chains. That risk is relevant whether your BMI is 27 or 37.

Step 3, Go through a proper clinical assessment

Knowing your BMI qualifies you in principle is different from being approved. When a prescriber reviews your consultation, they are checking far more than a number. They will look at which conditions you have documented, what other medicines you take, your blood pressure, your kidney function indicators, your plans around contraception if relevant, and whether anything in your history makes GLP-1 treatment unsuitable. The full eligibility breakdown for weight loss injections covers the common questions prescribers work through.

At nume, consultations are read the same day by a real GPhC-registered prescriber, a named clinician, not automated software. If you place your order before noon on a working day and are clinically approved, treatment dispatches that afternoon with DPD tracked delivery the next working day. That timing matters to people who have already waited months on NHS lists. The team behind the service and the clinical oversight behind every decision are available to review if you want to check our credentials before committing to anything.

For context on what the private route costs compared with what a headline price usually includes or excludes, the cost guide for weight loss injections explains the breakdown honestly. Short version: a legitimate price covers consultation, prescription, medicine and delivery together.

What to expect once treatment starts at a lower BMI

People starting at BMI 27 are often closer to their target weight than someone starting at BMI 35, which means the total duration of treatment, the absolute weight lost, and the titration path can all differ. Treatment typically opens at the starter dose (2.5mg weekly for tirzepatide) which exists to let your body adjust rather than as a therapeutic dose. The prescriber titrates from there based on tolerability and response.

Side effects are similar regardless of your starting BMI: nausea, loose stools, constipation, indigestion and reduced appetite are all common in the early weeks, particularly after a dose step. They tend to settle. Severe, persistent stomach pain that extends to the back warrants urgent medical attention and should not be waited out. The MHRA's Yellow Card scheme is there for patients to report unexpected effects, and our prescribers are available seven days a week if you have questions between doses.

For people thinking beyond the short term, the evidence page on whether GLP-1 injections support lasting weight loss is worth reading before you start, not after. Understanding what the data says about sustained outcomes helps set realistic expectations from day one.