Am I Eligible for Weight Loss Injections? BMI, Criteria and What to Expect

One of the most common questions from people considering Mounjaro or Wegovy is simply: do I qualify? Eligibility criteria can seem technical at first glance, and the difference between NHS and private prescribing adds another layer of confusion. Many people who would genuinely benefit from treatment assume they do not meet the bar, while others are unsure where to begin.

This guide sets out the eligibility criteria clearly, explains what affects them, and walks you through what to expect if you decide to book a consultation. There is no single answer that applies to everyone, which is exactly why a clinical consultation exists, but this article will give you a solid starting point.

What are the BMI criteria for weight loss injections in the UK?

In the UK, GLP-1 weight loss medications are licensed by the MHRA for adults with a BMI of 30 kg/m² or above, or 27 kg/m² or above with at least one weight-related health condition. These are the thresholds that apply to private prescribing through clinician-led services. [1]

NHS prescribing follows stricter thresholds set by NICE, which are discussed further below. Lower BMI thresholds also apply for people from certain ethnic backgrounds, including South Asian, Chinese, Middle Eastern, Black African, and African-Caribbean heritage, where the health risks associated with excess weight occur at a lower BMI. [2]

It is also worth understanding that BMI is one factor in eligibility, not the only one. Your medical history, existing health conditions, and previous attempts at weight management all form part of a proper clinical assessment.

"GLP-1 treatments can be highly effective, but they are not suitable for everyone. That's why a thorough eligibility assessment is such an important part of safe prescribing. Before recommending treatment, we take time to understand a patient's medical history, current medications, previous weight management attempts, and individual health goals.

At SwiftDoctor, our approach is centred on providing personalised, clinician-led care rather than a one-size-fits-all solution. We believe patients deserve a comprehensive assessment and ongoing support to ensure treatment is both safe and effective. The goal is not simply to prescribe medication, but to help patients build a sustainable plan that improves their long-term health and wellbeing."

— Dr Saira Bano, GP with a special interest in metabolic health and obesity at SwiftDoctor

Who is eligible for Mounjaro?

Mounjaro (tirzepatide) was licensed by the MHRA for chronic weight management in adults in November 2023. The licensed indication covers adults with a BMI of 30 kg/m² or above, or 27 kg/m² or above with at least one weight-related comorbidity, as part of a broader weight management programme that includes dietary and lifestyle changes. [1]

In a private prescribing context, eligibility for Mounjaro is assessed on an individual basis by a qualified clinician. As well as meeting the BMI threshold, patients should not have contraindications such as a personal or family history of medullary thyroid carcinoma, multiple endocrine neoplasia syndrome type 2 (MEN 2), or a history of pancreatitis. Previous thyroid conditions, severe renal impairment, and pregnancy are also contraindications. [1]

Mounjaro is only available to adults aged 18 and over, and treatment should always be accompanied by appropriate clinical oversight and follow-up.

Who is eligible for Wegovy?

Wegovy (semaglutide 2.4 mg) is licensed in the UK for chronic weight management in adults with a BMI of 30 kg/m² or above, or 27 kg/m² or above with at least one weight-related health condition. The licensed criteria are consistent with those for Mounjaro in the private prescribing context. [3]

The same contraindications apply: Wegovy is not appropriate for patients with a personal or family history of medullary thyroid carcinoma or MEN 2, a history of pancreatitis, or during pregnancy. It is a prescription-only medicine available to adults aged 18 and over. [3]

The practical difference between Mounjaro and Wegovy is not primarily in eligibility criteria but in mechanism, with Mounjaro being a dual GLP-1 and GIP agonist and Wegovy a GLP-1 agonist only. A clinician can help determine which is better suited to your individual circumstances.

What health conditions affect eligibility?

Certain health conditions can support eligibility for patients whose BMI sits just above 27 kg/m² rather than 30 kg/m². Weight-related comorbidities that may lower the threshold include type 2 diabetes, hypertension, high cholesterol or dyslipidaemia, obstructive sleep apnoea, and cardiovascular disease. The presence of one or more of these conditions signals that the health risks associated with excess weight are already being felt, which strengthens the clinical case for treatment. [1, 3]

Conversely, certain conditions mean that GLP-1 treatment is not appropriate regardless of BMI. These include a personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia syndrome type 2, a history of pancreatitis, severe gastrointestinal disease, pregnancy or breastfeeding, and some cases of severe renal impairment. A thorough medical history review at consultation will identify whether any of these apply to you. [1, 3]

Can I get weight loss injections on the NHS?

Both Wegovy and Mounjaro are technically available on the NHS, but access is significantly more restricted than through private prescribing and waiting times can be considerable.

For Wegovy, NICE guidance (TA875) recommends it for adults with a BMI of 35 kg/m² or above and at least one weight-related comorbidity, or a BMI of 30 kg/m² or above in specific circumstances. Treatment must be initiated and supervised within a specialist NHS weight management service, not by a GP, and patients must have already attempted other weight management interventions. [2]

For Mounjaro, NICE guidance (TA1026, December 2024) recommends it for weight management in adults with a BMI of at least 35 kg/m² and at least one weight-related comorbidity. A phased NHS rollout began in specialist weight management services from March 2025, with access extending to some GP surgeries from June 2025. However, NHS England has acknowledged the rollout will take up to 12 years to fully implement, meaning most eligible patients will face significant waiting periods. [4]

For patients who meet the clinical criteria but cannot or do not want to wait, private services like SwiftDoctor offer faster access to both treatments following a proper clinical consultation. Private prescribing follows the broader MHRA-licensed criteria rather than the more restrictive NICE thresholds, meaning a wider group of patients may be eligible.

What happens during a weight loss consultation?

A SwiftDoctor eligibility consultation is a straightforward, supportive process. It is not a test to pass or fail, and there is no judgement involved. The purpose is to ensure that treatment is appropriate and safe for you specifically.

During the consultation, a clinician will review your medical history, including any existing health conditions, current medications, and any contraindications that may affect prescribing. Your BMI and weight-related health profile will be assessed. You will have the opportunity to discuss which treatment option, Mounjaro or Wegovy, might be more suitable for your circumstances, and to ask any questions you have about how treatment works, what to expect, and how it will be monitored going forward.

If you are eligible, treatment can typically begin promptly. If you are not currently eligible, the clinician will explain why and discuss what options or next steps are available to you. To get started, book a consultation through SwiftDoctor at a time that suits you.

What if I am not eligible right now?

Not being eligible at this point is not the end of the road. There are several constructive paths forward depending on your circumstances.

If your BMI is currently below the threshold, structured lifestyle support, including dietary changes and increased physical activity, can help close the gap over time. Some patients find that working with a clinician on these foundational changes also addresses the underlying factors that make weight management difficult, sometimes without the need for medication at all.

If you have a health condition that currently contraindicates GLP-1 treatment, it is worth discussing with your GP whether that picture might change, or whether an alternative approach to weight management is available.

A consultation is never wasted, even if it does not immediately result in a prescription. Understanding where you stand clinically gives you useful information and a clearer path, whatever direction that points in.

Frequently Asked Questions

Can I be eligible for weight loss injections even if my BMI is under 30? 

Yes, in certain circumstances. If your BMI is 27 kg/m² or above and you have at least one weight-related health condition such as type 2 diabetes, hypertension, or sleep apnoea, you may still qualify. Eligibility is never determined by BMI alone, which is exactly why a clinical consultation exists rather than a simple online calculator.

Can I get weight loss injections if I have type 2 diabetes? 

Yes, and you may have more routes to access them than most. Type 2 diabetes is one of the comorbidities that can support eligibility at a lower BMI threshold. Both Mounjaro and semaglutide also have separate licensed indications for diabetes management, so your prescribing options may differ from those without a diabetes diagnosis.

Is there an age limit for GLP-1 weight loss treatment? 

GLP-1 weight loss medications are licensed for adults aged 18 to 85. They are not currently approved for weight management in children or adolescents, though research in younger populations is ongoing.

I have tried other weight loss approaches before. Does that affect my eligibility? 

On the NHS, having attempted other interventions is part of the eligibility criteria. In a private prescribing context it is less of a formal requirement, but your treatment history is still relevant to the clinical assessment. A clinician will take your full history into account when advising on the most appropriate next step.

How long does it take to start treatment after a consultation? 

Through SwiftDoctor, treatment can typically begin promptly following a consultation where eligibility is confirmed. The online process is designed to be fast, and medication is delivered discreetly once a prescription is issued. There is no waiting list as there would be through NHS referral pathways.

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Sources

1. Electronic Medicines Compendium (2024). Mounjaro 2.5 mg solution for injection: Summary of Product Characteristics. Eli Lilly. https://www.medicines.org.uk/emc/product/15484/smpc

2. NHS England (2025). Weight management injections: Wegovy and Mounjaro eligibility. https://www.england.nhs.uk/ourwork/prevention/obesity/medicines-for-obesity/weight-management-injections/

3. Electronic Medicines Compendium (2024). Wegovy 0.25 mg–2.4 mg solution for injection: Summary of Product Characteristics. Novo Nordisk. https://www.medicines.org.uk/emc/product/13616/smpc

4. NICE (2024). Tirzepatide for managing overweight and obesity (TA1026). https://www.nice.org.uk/guidance/ta1026