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Private Prescriptions for Weight Loss Injections

We are aware that many patients are now obtaining prescriptions for weight loss treatments through private providers.

When we are contacted by these providers, we explain that we cannot review your medical records on their behalf to check safety or contraindications. Our practice’s resources are dedicated to NHS care, and we do not have the capacity to undertake this work for private organisations. We therefore advise providers to ask patients to access their own medical history through the NHS App or online records. You can also request a copy of your medical notes directly from us to share with them.

For clarity, responsibility for checking your suitability for these medicines lies entirely with the prescribing clinician from the private service. They should not assume that no response from us means the treatment is safe for you.

Important advice for patients taking weight loss medication with the pill or HRT

These medicines slow stomach emptying, which can alter how well other medicines are absorbed.

If you take the contraceptive pill:

  • Tirzepatide (Mounjaro): may reduce pill effectiveness.
    • Consider a non-oral contraceptive (e.g. coil, implant), or
    • Use barrier protection (condoms) for 4 weeks after starting or increasing the dose.
  • Use extra protection (like condoms) if you have vomiting or diarrhoea and follow the missed pill rules (see the patient information leaflet which comes with your pill) if you vomit within 3 hours of taking the pill or have diarrhoea for more than 24 hours.
  • Semaglutide (Ozempic, Wegovy, Rybelsus): does not usually reduce pill effectiveness, but side effects such as vomiting or diarrhoea may still affect absorption. In these cases:
    • Use condoms as backup protection.
    • Follow “missed pill” instructions if you vomit within 3 hours of taking the pill or have diarrhoea for more than 24 hours.

Please see further information here: Patient Information GLP 1 agonists and contraception.

If you are on HRT:
If your HRT includes oral progesterone tablets (e.g. Utrogestan, norethisterone, medroxyprogesterone acetate), weight loss injections may reduce absorption. This can cause irregular bleeding and may reduce protection of the womb lining, which could increase cancer risk over time.

Possible alternatives include:

  • Mirena coil (IUS): Often the best option, lasting 5 years, provides both HRT support and contraception.
  • Combined HRT patch: Provides both oestrogen and progesterone through the skin.
  • Higher oral progesterone dose: Sometimes recommended for 4 weeks after starting or increasing medication.

Please contact us to discuss the best approach for your situation.

If you experience side effects

  • Common side effects include nausea, diarrhoea, vomiting, constipation, and abdominal pain.
  • These are often mild and settle with time, but if they are severe, persistent, or you notice unexpected symptoms (such as severe abdominal pain, ongoing vomiting, jaundice, or unusual bleeding), you should:
    • Contact your private prescribing provider promptly for advice.
    • If you feel unwell or unsafe, seek urgent medical care through NHS 111 or A&E.
    • Inform your GP of any serious side effects, especially if you require additional treatment.

Page published: 8 September 2025
Last updated: 19 September 2025