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Why does body temperature change when using a GLP-1?

There are a few reasons why your body temperature could change when using weight loss injections like Wegovy and Mounjaro. GLP-1 treatment affects a lot of different processes in your body, which can lead to you feeling colder or warmer for a number of different reasons. So let’s take a look at what might be happening in your body, what this can feel like, and how you can manage it.

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Alexandra Cristina Cowell, Writer & Clinical Content Reviewer

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Medically reviewed by

Dr Alexandra Cristina Cowell

Writer & Clinical Content Reviewer

on Mar 20, 2026.

Meet Alexandra Cristina

Last updated on Apr 24, 2026.

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Cause	What’s happening internally	How you will feel it	How to help
Insulation loss from weight loss	As you lose weight, you’ll lose body fat, which is part of your natural insulation.	With less natural insulation, you may be more sensitive to colder temperatures.	Layer up in cold weather to compensate for this lowered level of insulation.
Metabolic changes	Adaptive thermogenesis can start as you lose weight. This is where your body lowers your energy expenditure to compensate for reduced calorie intake.	Because your body is expending fewer calories, it’s producing less heat than it would by burning more calories.	High protein diets can reduce or help counteract adaptive thermogenesis. This is because protein takes more energy to digest than fats or carbohydrates, increasing your energy expenditure.
Brain thermostat changes	GLP-1 receptors in the hypothalamus act as your brain’s ‘thermostat’. GLP-1 treatment can activate these receptors, which could affect body temperature.	While there currently isn’t concrete evidence that GLP-1 treatment has a direct effect on the brain’s ability to control temperature, it’s thought that activating these receptors could lower your body’s ‘baseline’ temperature.	Getting out for regular walks can help improve blood flow to the brain, and could help the hypothalamus by reducing stress levels, supporting healthy hormone production, and regulating metabolism.
Brown fat changes	GLP-1 treatment can stimulate brown adipose tissue (BAT) thermogenesis, and the conversion of white adipose tissue (WAT) into BAT . Burning BAT acts as our body’s natural ‘heater’.	Because GLP-1 treatment stimulates the conversion of WAT to BAT, and BAT thermogenesis, you may feel warmer more often as your body burns through BAT.	It sounds counterproductive, but try to avoid cold temperatures if you’re struggling with hot flushes on GLP-1 treatment. BAT thermogenesis is activated in response to cold temperatures. So try to keep the temperature at around 20-22 degrees celsius to reduce BAT thermogenesis for heat.
Blood flow changes	Because your body temperature can drop on GLP-1 treatment, your brain could reduce circulation to your hands and feet to conserve heat and protect your organs.	This can cause your hands and feet to feel even colder.	Wear gloves and thick socks to keep your hands and feet warm. Staying hydrated, drinking electrolytes, and regular exercise can help stimulate circulation to your hands and feet, too.
Iron absorption changes	GLP-1 treatment helps you lose weight by slowing gastric emptying. But this can affect how well your body absorbs iron from your food.	Low iron levels can prevent your blood from carrying enough oxygen around your body. This means your body can limit circulation to your hands and feet to protect your organs, causing your extremities to feel cold.	Taking vitamin C can improve your iron absorption, which can help you increase your iron levels again. Eating high iron foods like legumes, red meat and green leafy veg alongside vitamin C can help increase your iron levels.
Blood pressure changes	GLP-1s promote natriuresis, which is where you excrete more sodium in your urine. It helps to lower your blood pressure when it’s high.	Lower blood pressure can cause your body to reduce blood flow to your skin, hands and feet to protect your organs.	Exercising can temporarily increase your blood pressure. Keeping hydrated and drinking electrolytes can also help improve circulation.
Muscle and fat ratio	Eating fewer calories can cause your body to burn muscle tissue for energy as well as fat.	Muscle is more metabolically active than fat, which means it generates more heat to maintain at rest. Less muscle means you’re burning fewer calories at rest, which can make you feel colder.	Eat a high-protein diet to maintain muscle, and try to focus on exercises that help to build muscle.

What causes you to feel cold when using weight loss injections?

Let’s take a more in-depth look at what causes you to feel cold when using GLP-1 treatment. We’ll examine what’s causing you to feel cold, how it’ll feel, and what you can do to help manage them.

Insulation loss from weight loss

As you restrict your calories and enter a deficit, you should start to lose body fat. This happens because your body starts to burn stored body fat for energy, because it’s not getting enough from your diet.

Body fat is a layer of insulation that helps keep heat inside your body. As you lose weight, this layer of insulation thins, meaning your body retains less heat. This can make you more sensitive to cold weather. Studies show that people with obesity lose heat less quickly, and need to raise their metabolism significantly less to keep warm than leaner individuals.

Layering up in cold temperatures can ‘replace’ this lost insulation, and help keep you warmer. Multiple layers of clothing create barriers that help to keep heat inside your body, and keep you warm.

Metabolic changes

GLP-1 treatment helps you lose weight by suppressing your appetite, which means you should eat fewer calories. Your body burns calories to produce heat and keep you warm, so with fewer calories available to burn, you might feel colder. This process is known as adaptive thermogenesis. It’s where your body’s energy expenditure drops to compensate for restricting your calorie intake.

A good way to help reduce adaptive thermogenesis is eating a diet that’s high in protein. High protein diets have been found to increase resting energy expenditure and help counteract adaptive thermogenesis. Protein takes more energy to digest and metabolise, and it supports muscle growth and maintenance. Because muscle tissue takes more calories to maintain, this can help burn more calories at rest. The more calories you burn, the more heat your body will produce, which can help if you’re feeling cold more often while using GLP-1 treatment.

Brain thermostat changes

GLP-1 treatment activates GLP-1 receptors in an area of your brain called the hypothalamus. The hypothalamus manages a lot of your body’s processes, like blood pressure, hunger, thirst, sleep, and body temperature.

Because GLP-1 treatment works in the area of the brain that helps manage your body temperature, it could have an effect on how cold you feel. One study found that treatment with GLP-1 hormone caused a significant reduction in temperature for two hours after use. While there’s no hard evidence that this reduction in temperature is due to the effects of GLP-1 treatment on the hypothalamus, it’s thought that activating these receptors in the hypothalamus could lower your body temperature, meaning you feel colder.

Regular physical activity, like getting out for walks and strength training, can help improve blood flow to your brain, and support your hypothalamus’s function. It can also help to reduce stress, too. Your hypothalamus is responsible for your body’s stress response, and high or persistent levels of stress can cause it to constantly produce stress hormones such as cortisol. So getting active can support your hypothalamus in a couple of different ways.

Brown fat changes

Brown fat, also known as brown adipose tissue (or BAT), is a specific kind of fat tissue that’s burned to generate heat. It breaks down sugar and fat molecules to generate body heat and maintain your body’s temperature. This process is called BAT thermogenesis. GLP-1 treatment can stimulate BAT thermogenesis, meaning you burn more fat for heat. It can also speed up the browning of white adipose tissue, so there’s more BAT to be burned for body heat. This could make you feel warmer than usual while using GLP-1 treatment.

If you’re struggling with hot flushes while using GLP-1 treatment, it could be because of BAT thermogenesis. There are a couple of things you can do to help. BAT thermogenesis is activated by your sympathetic nervous system in response to cold temperatures, to help warm your body back up. Keeping the ambient temperature at around 20-22 degrees Celsius, and insulating your body with layers of clothing, can help to reduce BAT thermogenesis and keep you from overheating.

Blood flow changes

If you’re already feeling cold because of the effects of GLP-1 treatment, your brain may start to pull blood away from your hands, feet, and skin to keep your internal organs warm. This can make you feel even colder, especially in your hands and feet.

Getting regular exercise can help improve your circulation, keeping the blood pumping to your extremities so they don’t get cold. Staying hydrated and drinking electrolytes can help to improve your circulation, too. And if all else fails, putting on some warm gloves and socks can help warm up your hands and feet if they’re feeling cold.

Iron absorption changes

Research shows that GLP-1 treatment could impact how well your body can absorb iron, leading to reduced levels in your blood. It’s thought to be because GLP-1 treatment slows down how quickly food leaves your stomach, which limits the amount of time iron spends in your small intestine (where it’s absorbed). Reduced appetite can also affect your iron levels. If you’re eating fewer calories because of GLP-1 treatment, there’s a good chance you’re eating less iron, too.

Less iron in your blood limits the amount of oxygen that your blood can carry around your body. To compensate for this, your body can limit circulation to your hands and feet to protect your internal organs, causing them to feel cold.

Eating plenty of high-iron foods, like red meat, legumes, tofu, leafy green vegetables, and fortified cereals is a good way of ensuring you’re getting enough iron. It’s important you pair iron with vitamin C-rich foods, like citrus and bell peppers, because vitamin C is crucial for iron absorption.

Blood pressure changes

GLP-1 treatment can help promote a process called natriuresis. This is where you excrete more sodium in your urine to lower your blood pressure and the volume of blood in your body. Lower blood pressure can limit your body’s ability to circulate blood to your hands and feet. This means less warmth is reaching them, and they could feel colder as a result.

Exercising can temporarily raise your blood pressure, which can help your body circulate blood to your extremities more easily, warming them up. Staying hydrated and making sure you get enough electrolytes can also help improve your circulation, so more blood (and warmth) can reach your hands and feet.

Muscle and fat ratio

Muscle tissue is more metabolically active than fat, which means it requires more calories to maintain itself at rest. Restricting your calories too much can cause your body to break down muscle tissue for energy instead of fat. Carrying less muscle means you’re burning fewer calories for energy and warmth at rest, meaning you may feel colder. Research suggests that people with a higher muscle ratio may be able to better maintain their body temperature in cold conditions.

Focusing on strength training exercises to build muscle, and eating a high protein diet, can help you maintain muscle mass while eating a calorie deficit. Because protein takes more calories to digest than carbohydrates and fat, your body produces more heat by digesting it, too. This could help assist with your weight loss, and keep you warm while using GLP-1 treatment. Protein also helps you feel more satisfied after eating, which could make it easier to stick to a calorie deficit.

When to see a clinician

If you’re worried about changes in your body temperature while on GLP-1 treatment, speak to your clinician. Areas of concern could include:

cold hands and feet, possibly caused by changes in your blood pressure, blood flow, or iron levels
low TSH levels, which can manifest as reduced body temperature, fast or irregular heartbeat, anxiety, tremor, insomnia, sweating, or frequent bowel movements

Your clinician may suggest medication (like iron supplements or TSH replacement therapy) to treat any underlying problems that are causing these body temperature changes. They may also suggest lifestyle changes, like strength training, eating more protein, or drinking more water. But it might be that moving to another weight loss treatment, reducing your dose, or stopping GLP-1 treatment could be the best option to manage your body temperature, if it isn’t caused by an underlying condition.

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Disclaimer: The information provided on this page is not a substitute for professional medical advice, diagnosis, or treatment. If you have any questions or concerns about your health, please talk to a doctor.

Why does body temperature change when using a GLP-1?

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What causes you to feel cold when using weight loss injections?

Insulation loss from weight loss

Metabolic changes

Brain thermostat changes

Brown fat changes

Blood flow changes

Iron absorption changes

Blood pressure changes

Muscle and fat ratio

When to see a clinician

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