Before you use this guide
This is general information, not a diagnosis or a substitute for care from a clinician who knows your medical history. Seek urgent help for severe or rapidly worsening symptoms.
The short answer: a clinical decision, not a product choice
Some prescription-only medicines are licensed to support weight management in eligible adults. They act on signals involved in appetite, fullness and blood-glucose regulation, and they are intended to be used alongside a reduced-calorie eating plan and increased physical activity.
Whether any medicine is appropriate—and which one—is decided by a prescriber after reviewing your health. These medicines are not a cosmetic quick fix, and they should never be bought from an unregulated seller or used without a prescribing assessment.
Who may be eligible?
Licensed use generally includes adults living with obesity, or adults who are overweight and have at least one weight-related health condition. A prescriber must still assess whether treatment is appropriate. BMI is only one part of that decision.
Medical history, current medicines, previous weight-management treatment, pregnancy plans, digestive symptoms and conditions affecting the pancreas, gallbladder or endocrine system may all be relevant. NHS access criteria and rollout arrangements are more restrictive than the full licensed indication, so NHS eligibility should not be assumed from private eligibility—or vice versa.
What results are realistic?
Clinical studies show that prescription treatment can support meaningful weight loss for many eligible patients, but an average trial result cannot predict an individual outcome, and results cannot be guaranteed.
A clinician weighs potential benefit against contraindications, side effects, other medication, previous response and the support you can sustain. Treatment should be reviewed if it is not producing sufficient benefit or adverse effects are difficult to manage.
Side effects and important safety points
Nausea, vomiting, diarrhoea, constipation and abdominal discomfort are common, especially while the dose is being increased. Gradual dose changes are designed to improve tolerability, so follow the prescribed schedule rather than increasing more quickly.
Seek clinical advice for persistent vomiting, dehydration or severe abdominal pain. Tell healthcare professionals about your weight-management medicine before surgery or a procedure involving sedation. These medicines should not be used during pregnancy, while trying to become pregnant or while breastfeeding.
Some of these medicines can reduce the effectiveness of oral contraception, and some need to be stopped for a set period before a planned pregnancy. Your prescriber will explain what applies to your treatment.
Why the programme around the prescription matters
Medication can reduce appetite, but long-term health still depends on adequate nutrition, maintaining muscle, activity, sleep and practical habits. Monitoring can identify side effects, review progress and help avoid unsafe dose changes or inadequate food intake.
A useful programme should explain what happens if treatment is paused or stopped, how prescriptions are reviewed, who to contact with side effects and how weight, waist or body-composition trends will be interpreted. Jace offers clinician-led assessment and ongoing support rather than treating a prescription as a standalone product.
Common questions
Questions about this topic.
No. You can share your preferences and any previous treatment, but the prescriber decides whether a medicine is appropriate and which one is suitable for you.
About the author
Written by Dr John T. Doherty, consultant doctor and founder of Jace Medical, an RQIA-registered private healthcare provider with clinics in Greysteel and Letterkenny.
Sources and further reading
We use authoritative UK guidance and patient information. External sources may be updated after this guide is published.
