Why am I cold on GLP-1 treatment?

If you’re taking a GLP-1 medicine, like Mounjaro or Wegovy, and finding yourself unusually cold, you’re not imagining it. While coldness isn’t listed as a side effect in the patient information leaflet, many of our patients report it, especially during the early stages of treatment or when they’re losing weight quickly.

This article explains why it happens, how it relates to the way GLP-1s work, and what you can do to feel more comfortable.

Is feeling cold a side effect of GLP-1s?

Technically, no. Feeling cold isn’t listed as a known side effect in the official guidance for GLP-1 medicines like tirzepatide or semaglutide.

But many people taking these treatments notice that they feel colder than usual, especially when:

• Their calorie intake has reduced
• They’re losing weight rapidly
• They’re skipping meals or under-eating

So while it’s not a direct effect of the medicine itself, it is closely linked to what the medicine does.

GLP-1s help reduce appetite and portion size. That means you’re often eating less, lowering your calorie intake, and fewer calories means your body produces less heat. At the same time, as you lose weight, you may have less insulation to keep you warm. It’s also possible that blood sugar changes and hormonal shifts play a role.

What’s happening in your body?

GLP-1 medicines help your body regulate hunger and fullness. But they also:

• Slow how quickly food moves through your stomach
• Support lower blood sugar levels
• Help reduce cravings and snacking

All of this means your body may be burning fewer calories, storing less energy, or adjusting to a new rhythm. That can affect your internal temperature.

Some people notice the cold more in their hands and feet. Others feel it after eating much smaller meals than they’re used to. If you’ve been feeling colder since starting treatment, it may simply be a sign that your body is adapting to this new phase.

Should I be worried?

Usually, no. Feeling colder than usual is a normal response to weight loss and lower calorie intake. But there are a few situations where it’s worth checking:

• If you’re skipping meals or eating very little
• If your hands and feet are always cold, even indoors
• If you’re feeling faint, dizzy or lightheaded
• If you’re combining GLP-1 treatment with intense calorie restriction

GLP-1 medicines are designed to be used alongside moderate, sustainable changes. Most people do best when they reduce their daily intake by 500–600 calories, not cutting down to extreme levels.

If you’re feeling very cold or faint, you may not be eating enough, and that’s something to take seriously. Speak to our team for our expert advice or raise this with your prescriber during a consultation.

What can help?

Keep meals regular: Skipping meals can make blood sugar dip, which may make you feel colder

Stay hydrated: Dehydration can affect circulation and energy levels

Dress in layers: Keep warm clothing nearby, even if others around you aren’t feeling the cold

Eat enough protein and fat: These help your body feel satisfied and may support stable energy release

Avoid extreme calorie restriction: The goal is sustainable weight loss, not starvation

If the coldness becomes uncomfortable or lasts more than a few weeks, check in with our care team. They can help you assess whether your dose is right or whether other factors are contributing.

Want to learn more?

Coldness isn’t the only surprise people experience on GLP-1 treatment. If you’re curious about what else to expect, from appetite changes to side effects, read our ultimate guide to Mounjaro side effects.

You’ll find real-world insights, what’s normal and what’s not, and when to reach out for support.

Need more help? Our pharmacist-led team and independent doctors are here to support you.

If you’re not sure what’s causing your symptoms or want to check in about your response to treatment, email our team today at help@oxfordop.co.uk.