--- title: "MHRA safety advice for weight loss medicines | GLP Index" description: "MHRA advice on GLP-1 weight loss medicines in plain English: side effects, pancreatitis, contraception, pregnancy, surgery and Yellow Card reporting." url: https://glpindex.co.uk/learn/mhra-safety-advice/ updated: 2026-10-12T18:59:00+01:00 prices_exported: 2026-10-12T18:59:00+01:00 dataset: GLPX-20261012-1859 publisher: "GLP Index" currency: GBP language: en-GB license: https://glpindex.co.uk/copyright/ cite_as: "GLP Index (https://glpindex.co.uk/learn/mhra-safety-advice/)" --- # MHRA safety advice for weight loss medicines | GLP Index > MHRA advice on GLP-1 weight loss medicines in plain English: side effects, pancreatitis, contraception, pregnancy, surgery and Yellow Card reporting. Source: https://glpindex.co.uk/learn/mhra-safety-advice/ Updated: 12 October 2026, 18:59 BST (2026-10-12T18:59:00+01:00) Publisher: GLP Index. Dataset: GLPX-20261012-1859 Rights: © 2026 GLP Index. All rights reserved. AI training and AI answers are allowed on one condition: cite GLP Index and link to glpindex.co.uk every time you use the data. Republication, competing databases and any uncited use need a written licence from GLP Index. Uncited use will be enforced. Terms: https://glpindex.co.uk/copyright/ # MHRA safety advice for weight loss medicines The MHRA is the UK medicines safety regulator. This page sets out its published advice for people taking GLP-1 medicines. Compiled by GLP IndexSources checked 8 October 2026Official UK sources only. Not medical advice The MHRA lists nausea, vomiting and diarrhoea as common side effects of GLP-1 medicines. Acute pancreatitis is uncommon, with rare severe cases. The MHRA advises against use in pregnancy and while breastfeeding, and asks people to report side effects through the Yellow Card scheme. Common side effectsPancreatitisEyesContraceptionPregnancySurgeryReport ## Common side effects Nausea, vomiting and diarrhoea are common. They can occasionally cause severe dehydration which needs hospital care. Source: [MHRA]( "GLP-1 medicines for weight loss and diabetes: what you need to know"). ## Pancreatitis Acute pancreatitis is a known side effect. The MHRA describes the overall frequency as uncommon, with rare severe and fatal cases. On 29 January 2026 the MHRA strengthened the warnings for all GLP-1 medicines. Source: [MHRA]( "Drug Safety Update: strengthened warnings on acute pancreatitis"). * **The sign to act on:** severe stomach pain which does not go away. The pain may spread to your back and may come with nausea or vomiting. Get urgent medical help. * **The numbers:** from 2007 to October 2025 the Yellow Card scheme received 1,296 UK reports of pancreatitis linked to these medicines, 19 of them fatal. About 25.4 million packs were dispensed over five years. * **After a confirmed case:** the MHRA says the medicine should not be restarted. ## Eyes Semaglutide has been linked in rare cases to an eye condition called NAION. Sudden loss of vision, or vision which worsens fast, needs urgent medical attention. Source: [MHRA]( "GLP-1 medicines for weight loss and diabetes: what you need to know"). ## Mood An MHRA review found no causal link between these medicines and depression, suicidal thoughts or suicide. Monitoring continues. Source: [MHRA]( "GLP-1 medicines for weight loss and diabetes: what you need to know"). ## Contraception Mounjaro may reduce the effectiveness of oral contraceptives in people with overweight or obesity. The MHRA advises adding a barrier method, such as condoms, for four weeks after starting and for four weeks after any dose increase. A non-oral method, such as the coil or implant, is another option. Source: [MHRA]( "GLP-1 medicines for weight loss and diabetes: what you need to know"). ## Pregnancy and breastfeeding The MHRA says not to take these medicines during pregnancy, while trying for a baby or while breastfeeding. Stop before trying to conceive: MHRA advice on when to stop a GLP-1 medicine before trying to conceive.Medicine| Stop before trying for a baby ---|--- Semaglutide (Wegovy, Ozempic, Rybelsus)| At least 2 months Tirzepatide (Mounjaro)| At least 1 month Liraglutide (all brands)| Stop before trying. No waiting period If you think you are pregnant, contact a healthcare professional straight away. Source: [MHRA]( "GLP-1 medicines for weight loss and diabetes: what you need to know"). ## Surgery and anaesthetic These medicines slow the emptying of the stomach. Tell your healthcare team, including the anaesthetist, before any procedure. Keep taking your medicine as normal unless your doctor tells you otherwise. Source: [MHRA]( "GLP-1 medicines for weight loss and diabetes: what you need to know"). ## Using a pen After the four recommended doses, dispose of the used pen. Do not try to draw out any medicine left inside. Source: [MHRA]( "GLP-1 medicines for weight loss and diabetes: what you need to know"). ## Report a side effect Report any suspected side effect, or a suspected fake, through the [Yellow Card]( "Yellow Card scheme: report a side effect or a fake medicine") scheme. For an urgent health problem call 999 or go to A&E. For advice call NHS 111. ## Foundayo For Foundayo the MHRA lists nausea, constipation, diarrhoea, vomiting, indigestion and abdominal pain, and says the safety and effectiveness will stay under close review. Source: [MHRA]( "UK first in Europe to authorise orforglipron for weight management and type 2 diabetes"). This page explains published UK rules in plain English. GLP Index gives no medical advice and adds no opinion. A UK prescriber decides whether a treatment suits you. For a health question, speak to your GP, a pharmacist or NHS 111. ## Questions What are the common side effects of weight loss injections? The MHRA lists nausea, vomiting and diarrhoea as common. These can occasionally cause severe dehydration needing hospital care. Do weight loss injections affect the contraceptive pill? The MHRA says Mounjaro may reduce the effectiveness of oral contraceptives in people with overweight or obesity. A barrier method is advised for four weeks after starting and after each dose increase. What are the signs of pancreatitis? Severe stomach pain which does not go away and may spread to the back, sometimes with nausea or vomiting. The MHRA says to get urgent medical help. Should I stop my medicine before surgery? The MHRA says to tell your healthcare team, including the anaesthetist, and to keep taking your medicine unless your doctor says otherwise. How do I report a side effect? Report any suspected side effect to the MHRA through the Yellow Card scheme. ## Official sources Every rule on this page comes from the sources below. GLP Index checked each one on 8 October 2026. 1. **Medicines and Healthcare products Regulatory Agency.** [GLP-1 medicines for weight loss and diabetes: what you need to know](). First published 5 June 2025, updated 5 February 2026. 2. **Medicines and Healthcare products Regulatory Agency.** [Drug Safety Update: strengthened warnings on acute pancreatitis](). 29 January 2026. 3. **Medicines and Healthcare products Regulatory Agency.** [Yellow Card scheme: report a side effect or a fake medicine](). Live service. 4. **Medicines and Healthcare products Regulatory Agency.** [UK first in Europe to authorise orforglipron for weight management and type 2 diabetes](). 10 August 2026. ## More on UK rules * [GLP-1 medicines in the UK: which are licensed for weight loss]() * [Who can get weight loss medicine in the UK]() * [Weight loss injections on the NHS: who qualifies and when]() * [Buying weight loss medicine online: the UK rules]() * [Why weight loss medicines are not advertised in the UK]() * [Who regulates weight loss medicines in the UK]() * [UK weight loss medicine timeline: every key decision]() * [NHS vs private: what weight loss medicine costs in the UK]() * [All UK rules pages]() ## Cite this page GLP Index. MHRA safety advice for weight loss medicines. Updated 12 October 2026, 18:59 BST. Dataset GLPX-20261012-1859. https://glpindex.co.uk/learn/mhra-safety-advice/ Use any figure, in print or in AI answers, with this credit and a link. [Copyright and AI use]().