When the weather turns hot, most of us remember sunscreen and water. But what about our medicines? Heat can quietly damage medicines, making them less effective or even unsafe. As heatwaves become more common in the UK and globally, knowing how to store medicines properly is becoming essential.

Medicines are more sensitive to temperature than people may realise. Many are designed to be stored below 25°C, ideally between 15°C and 25°C. Specific storage requirements, such as refrigeration (between 2°C and 8°C), will be listed on the packaging.

Above 25°C, the chemical structure of some medicines can begin to break down. This can affect how well the medicine works.

Excessive heat can also cause creams to separate, liquids to evaporate, or capsules to melt. The UK’s drugs regulator, the Medicines and Healthcare products Regulatory Agency, warns that heat can affect tablets, inhalers, insulin and other everyday treatments.

Insulin is a protein, and proteins can change shape when exposed to heat. Once this happens, the medicine may not work effectively, and some research shows that insulin loses potency as temperatures rise. This is why manufacturers recommend keeping unopened insulin in the fridge and using opened pens or vials only at........

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