Mounjaro and Hot Weather:
Staying Safe in the Heat (UK Guide)

When temperatures rise, your body cools itself through sweat and increased skin blood flow. If you use Mounjaro (tirzepatide), two factors matter: GLP 1 medications can reduce thirst and food intake, and hot weather increases fluid loss. Even if you do not feel uncomfortably hot, you can still become dehydrated.

The UKHSA heat-health alerts publishes heat health guidance during alerts worth following alongside the tips below.

Some users report feeling unusually cold even during hot weather. Possible contributors include changes in metabolism, blood pressure– related circulation, and how temperature is perceived while on a GLP 1 / GIP agonist. For a fuller explanation, read why you may feel cold on Mounjaro.

Mounjaro can reduce appetite and thirst cues, making it easier to under drink especially if you are also managing nausea or digestive side effects.

• Drink regularly throughout the day on a schedule—not only when thirsty
• In hot weather or during exercise, many adults need more than 2 litres of fluid from drinks plus water in food; adjust for sweat and activity
• Keep a bottle of water within reach and sip between meals
• Include hydrating foods: fruit, yoghurt, soups (if tolerated)
• Limit excess alcohol and high caffeine intake, which can worsen dehydration

Some people notice increased skin sensitivity or burn more easily in the sun while losing weight or on new medications. Regardless of cause, standard sun safety applies:

• Use broad-spectrum sunscreen SPF 30 or higher, reapplied as directed
• Wear light, loose clothing, a wide-brimmed hat, and sunglasses in strong sun
• Seek shade between late morning and mid-afternoon when UV is strongest

NHS sun safety guidance: Sunscreen and sun safety.

• Hydrate on a schedule — set phone reminders if you tend to forget to drink on Mounjaro.
• Rest if dizzy, faint, or nauseated — these can be early signs of heat exhaustion; see NHS heat exhaustion guidance.
• Monitor digestive symptoms — vomiting or diarrhoea from any cause plus heat is high-risk for dehydration; see norovirus & GLP-1 guidance if relevant.
• Seek advice if symptoms worsen — confusion, not passing urine, or a sustained fast heart rate need urgent assessment.