The Medicines and Healthcare products Regulatory Agency has issued advice for people who use insulin or are prescribed metformin as the UK's amber heat health alert is extended12:08, 27 May 2026Updated 12:08, 27 May 2026People who use insulin or take metformin are being warned as the UK braces itself for yet more scorching weather and an amber health alert. The record for the hottest May temperature in the UK was broken for the second day running, with 35C being recorded at two locations — Heathrow and Kew Gardens in London.‌The UK Health Security Agency (UKHSA) has now issued an extended amber health warning covering the south-west, south-east, London, East and West Midlands and the west of England.‌The amber alert, alongside yellow alerts for the north-east and north-west, will remain in place until 5pm on Thursday.‌Under the UKHSA and Met Office's Weather-Health alerting system, an amber Heat Health alert signals that impacts are likely to include increased demand on health care services from vulnerable groups, as well as a heightened health risk for those aged over 65 or living with pre-existing medical conditions.Dr Anya Gopfert, Consultant in Health Protection at UKHSA, said: "We know that even moderate heat can lead to serious health problems, especially for older people and those with certain health conditions, so it's important that everyone takes simple precautions while enjoying the warm weather over the coming days.""If you have friends, family or neighbours who are more vulnerable, it is important to check in on them and ensure they are aware of the forecasts and are following the necessary advice." The Medicines and Healthcare products Regulatory Agency is also cautioning those who use insulin or are prescribed metformin to exercise extreme care during warm weather.‌These medicines, used to manage diabetes, can heighten the risk of dehydration or make early warning signs harder to recognise.Antipsychotic medications, such as olanzapine or quetiapine, or stimulant medications for attention disorders can raise your body temperature, making it easier to overheat.Dehydration can trigger dizziness, headaches, fatigue, confusion, and dark urine — posing a particularly serious risk to older adults, young children, and those with heart or kidney conditions.‌Experts recommend that anyone who begins to feel unwell in the heat should move to a cooler location, sip water slowly, and seek medical advice if symptoms fail to improve promptly.Alison Cave, Chief Safety Officer at the MHRA, said: "Let's face it – when there's a heatwave, most of us are focused on getting outside and enjoying it while it lasts. But it's easy to forget that medicines left in the heat – in cars, bags, or on sunny windowsills – might not work properly when you need them."Some medicines can also make you more likely to burn in the sun, feel dizzy, or get dehydrated, especially if you're taking diuretics or have a condition like asthma, heart disease, or diabetes.Article continues below"To stay safe in the heat; Store medicines somewhere cool, dry and out of direct sunlight – especially if you're out and about, Know the signs of heat-related illness – stay hydrated and listen to your body and take extra care in the sun if your medicine makes your skin more likely to burn"And remember, for all medicines it's important to read the leaflet and speak to a healthcare professional if you have any questions."