Who Can Be Prescribed Weight Loss Medication in the UK?
Who Can Be Prescribed Weight Loss Medication in the UK?
Prescription weight loss medicines have become much more widely discussed in recent years.
But they are not suitable for everyone, and wanting to lose weight does not automatically mean that a prescription medicine is appropriate.
Whether someone can be prescribed weight loss medication depends on factors including their BMI, medical history, weight related health conditions, current medicines and an individual clinical assessment.
There is also an important difference between being potentially suitable for a licensed treatment and qualifying to receive that treatment through the NHS.
Here is what you need to know.
What Types of Prescription Weight Loss Medication Are Available?
There are several prescription medicines licensed for weight management in the UK.
These include medicines that affect appetite and feelings of fullness, as well as medicines that reduce the amount of dietary fat absorbed by the body.
Some of the better known treatments include tirzepatide, semaglutide and orlistat.
The eligibility criteria are not identical for every medicine.
For example, the UK marketing authorisation for tirzepatide for weight management includes adults with a BMI of 30 or above, or a BMI of 27 to below 30 where at least one weight related health condition is also present. Similar BMI criteria apply to several semaglutide weight management products.
Orlistat has different criteria and may be considered at a BMI of 30 or above, or from a BMI of 28 where associated risk factors are present.
Meeting these criteria does not mean that a medicine will automatically be prescribed.
A clinician still needs to decide whether treatment is safe and appropriate for that individual.
Does Your BMI Affect Eligibility?
Yes. BMI is one of the main factors considered when assessing someone for prescription weight management treatment.
BMI, or Body Mass Index, uses your height and weight to estimate whether your weight falls within a healthy range.
For many licensed prescription weight management medicines, the relevant starting point for adults is generally:
BMI of 30 or above
or
BMI of 27 or above with at least one relevant weight related health condition
The exact criteria depend on the medicine being considered.
BMI is useful, but it is not a complete assessment of someone's health.
A clinician may also consider factors such as waist measurement, existing health conditions, previous attempts to manage weight, current medication and the potential risks and benefits of treatment.
What Is a Weight Related Health Condition?
Someone with a BMI below 30 may sometimes meet the licensed criteria for certain weight management medicines if they also have a health condition associated with excess weight.
Examples can include:
High blood pressure Abnormal cholesterol or blood fat levels Prediabetes Type 2 diabetes Obstructive sleep apnoea Cardiovascular disease
These are examples rather than a complete list.
This is one reason why an online BMI calculator alone cannot tell you whether prescription treatment is appropriate.
Is BMI the Only Thing a Doctor Looks At?
No.
BMI can help determine whether someone falls within the licensed treatment criteria, but prescribing decisions involve much more than a number on the scales.
Before prescribing, a clinician may need to understand:
Your current weight and height Your medical history Any existing medical conditions Medicines you currently take Previous weight management approaches Pregnancy or plans for pregnancy where relevant Previous reactions to medicines Your eating habits and relationship with food Whether there are symptoms requiring further investigation Whether the benefits of treatment are likely to outweigh the risks
NICE guidance recommends that weight management medicines are used as part of a wider approach that also includes appropriate dietary, physical activity and behavioural support.
Can Someone With a BMI Under 30 Be Prescribed Weight Loss Medication?
Potentially, depending on the medicine and the person's health.
For several modern weight management treatments, an adult with a BMI between 27 and 30 may fall within the licensed indication if they also have at least one relevant weight related medical condition.
That does not mean everyone with a BMI of 27 or above qualifies.
If there are no relevant health conditions, the licensed criteria for that particular medicine may not be met.
Different medicines also have different eligibility requirements, so treatment always needs to be considered individually.
Can You Get Weight Loss Medication With a BMI Over 30?
A BMI of 30 or above falls within the licensed weight management indication for several prescription medicines used in the UK.
However, BMI eligibility and clinical suitability are not the same thing.
Someone may meet the BMI requirement but have another medical issue that makes a particular treatment unsuitable.
Equally, the clinician may need additional information before making a prescribing decision.
Can You Get Weight Loss Medication Privately?
Yes. Prescription weight management treatment can be provided privately where an appropriately qualified prescriber assesses the patient and decides that treatment is clinically appropriate.
Private prescribing is different from NHS access.
A private clinician still needs to prescribe responsibly and in accordance with relevant professional standards, the medicine's authorised use and the individual patient's circumstances.
Paying privately does not remove the need for a proper clinical assessment.
Legitimate prescription weight loss medicines should be supplied through an appropriate pharmacy following a valid prescription.
The MHRA has repeatedly warned against purchasing weight loss medicines from social media accounts, unverified websites or other unauthorised sellers because falsified and unlicensed products can present serious health risks.
Is NHS Eligibility Different?
Yes, and this causes a lot of confusion.
A medicine can be licensed for use in a broader group of patients while NHS funding criteria are narrower.
For example, tirzepatide is licensed for weight management in adults with obesity, or some adults who are overweight and have a weight related condition. However, NICE recommends tirzepatide through the NHS for weight management in adults with an initial BMI of at least 35 and at least one weight related comorbidity, with lower BMI thresholds used for some ethnic backgrounds.
NHS access can also depend on how services are commissioned and introduced locally.
So someone who does not currently qualify for NHS treatment may still potentially meet the licensed criteria for private treatment.
That still requires an individual clinical assessment.
What About Weight Loss Medication in Northern Ireland?
Northern Ireland is currently developing its NHS weight management services.
In June 2026, the Department of Health announced the first phase of Northern Ireland's new Regional Obesity Management Service, with implementation expected to begin during autumn 2026.
The initial phase is aimed at people with the highest clinical need. The announced criteria include adults aged 18 and over with a BMI above 45 and at least one specified weight related condition.
The Department has stated that access will expand in phases and that medication will be provided where clinically appropriate alongside wider weight management support.
This means the criteria for obtaining treatment through Health and Social Care in Northern Ireland can be considerably different from the criteria applying to private prescribing.
You can read more in our guide to Northern Ireland's New Obesity Management Service: Who Qualifies and How Will It Work?
Do You Need to Have Tried Diet and Exercise First?
Weight management medication is not intended to completely replace changes to diet, activity or other aspects of health.
Licensed GLP 1 based weight management medicines are generally authorised for use alongside a reduced calorie diet and increased physical activity.
That does not mean everyone must follow a particular commercial diet or spend hours in a gym.
Weight management is individual, and realistic changes can look very different between patients.
A clinician may discuss previous attempts to lose weight and what support might make treatment more effective and sustainable.
Do You Have to Have Diabetes?
No.
Some weight management medicines are also used in the treatment of type 2 diabetes, which can cause confusion.
However, certain medicines have separate UK authorisations specifically for weight management.
You do not necessarily need to have diabetes to be considered for prescription weight loss treatment.
For example, tirzepatide is authorised for weight management in adults who meet its relevant BMI and health criteria, regardless of whether they have diabetes.
Can Weight Loss Medication Be Prescribed During Pregnancy?
Weight loss medicines are generally not appropriate during pregnancy.
Specific medicines also have their own restrictions regarding pregnancy, breastfeeding and contraception.
For example, NHS guidance states that tirzepatide is not recommended during pregnancy or when planning pregnancy.
Anyone who is pregnant, trying for a baby or breastfeeding should tell their clinician before any weight management medicine is considered.
Why Might Someone Be Refused Weight Loss Medication?
There are many possible reasons.
Someone may not meet the licensed criteria for a particular treatment.
Alternatively, the clinician may believe that the medicine is unsuitable because of the patient's medical history, current medication or another health concern.
A clinician may also need further information or investigations before making a decision.
Being declined one particular medicine does not necessarily mean that there are no weight management options available.
The aim of an assessment should be to identify an approach that is safe and appropriate for the individual rather than simply issuing a requested prescription.
What Happens During a Weight Management Assessment?
The exact process varies between providers.
A clinical assessment will usually gather enough information for the prescriber to understand your general health, current weight and potential treatment risks.
This may include questions about:
Height and weight Existing health conditions Current medication Previous weight management attempts Allergies Relevant family history Lifestyle Pregnancy where relevant Previous or current weight management medicines
Some remote services may also require weight verification or identity verification before prescribing.
The clinician can then decide whether prescription treatment should be considered.
Does Meeting the Criteria Guarantee a Prescription?
No.
This is probably the most important point.
Eligibility criteria tell a clinician who may potentially be considered for treatment. They do not guarantee that treatment will be prescribed.
Prescription weight management medicines can cause side effects and are not appropriate for every patient.
The final decision should always be made following an individual clinical assessment.
The Bottom Line
Who can be prescribed weight loss medication in the UK depends on both eligibility and clinical suitability.
For several commonly used prescription weight management medicines, adults may potentially fall within the licensed criteria if they:
Have a BMI of 30 or above
or
Have a BMI of at least 27 together with an appropriate weight related health condition
However, the exact rules vary between medicines.
NHS eligibility can also be considerably more restrictive than the licensed criteria used when considering private treatment.
Your BMI is only one part of the picture. Medical history, current medicines, existing conditions and individual risk all need to be considered before a prescription is issued.
If you are considering prescription weight management treatment, the appropriate next step is a clinical assessment with a qualified healthcare professional who can discuss the available options and whether any of them may be suitable for you.
Keltoi Wellness is a doctor led telehealth service. Any prescription treatment is subject to an individual clinical assessment and prescribing decisions are made independently by the treating clinician.