Feeling Cold and Night Sweats on a GLP-1: What the Labels and Studies Show

No trial has measured body temperature in people taking Ozempic, Wegovy, Mounjaro or Zepbound, and none of their labels lists chills, feeling cold, excess sweating or night sweats as a side effect.^[1][3] People report all four anyway. The best-supported explanation for feeling cold is the weight loss and the smaller meals, not a direct drug effect: in a diet trial, core temperature fell as people lost about 10% of their weight.^[8] Sweating is different. Every label lists it as a sign of low blood sugar, and that risk sits mostly with people whose regimen already includes insulin or a sulfonylurea.^[1] Thyroid problems, menopause and other medicines explain many of the rest.

What the labels say: nothing about feeling cold

We searched the full current label of each major GLP-1 drug for chills, cold, hyperhidrosis (the medical term for excess sweating), night sweats, temperature and fever. The result was the same across all six. None lists feeling cold or chills as an adverse reaction. The word “cold” appears only in the pen storage instructions. Sweating appears once in each, inside the patient guide’s list of low-blood-sugar symptoms.^[1][2]

Absence from a label does not prove a drug never does something. Adverse reaction tables list events that happened more often on the drug than on placebo in trials, usually at a frequency cutoff, so a mild, subjective feeling of being cold could go uncounted. It does mean that in trials of tens of thousands of people, nothing about temperature stood out enough to make the list.

What people report to FDA

FDA’s adverse event reporting system collects reports from patients, doctors and manufacturers. Anyone can file one, nobody checks whether the drug caused the problem, and popular drugs collect more reports simply because more people take them. The counts below are reports that list each drug and each symptom, through June 2026.^[7]

Each temperature term turns up in well under 1% of the reports for either drug. That is a signal that people notice these symptoms and connect them to the drug. It is not evidence of how often the drug causes them, or whether it does at all. A study of nearly 60,000 Facebook posts about GLP-1 drugs found sweating mentioned in the same cluster as hypoglycemia, dizziness and dehydration,^[28] which fits the label’s own link between sweating and low blood sugar.

Why losing weight can make you feel colder

Feeling cold after major weight loss is not unique to these drugs. The human evidence comes from diet studies, and it points to three mechanisms. None has been tested directly in people on a GLP-1, so treat their application to Ozempic or Mounjaro as inference.

The body runs slightly cooler on fewer calories. In a six-month randomized trial at Pennington Biomedical, 48 overweight adults were assigned to a maintenance diet, a 25% calorie cut, a smaller cut plus exercise, or a very low-calorie diet. Those cutting calories lost about 10% of their weight, and core body temperature fell in both calorie-restriction groups.^[8] The larger two-year CALERIE 2 trial, in 218 people, found little difference in core temperature between groups, but blood levels of T3, the active thyroid hormone that sets the pace of heat production, fell more in the restricted group at one and two years.^[9] A small study at Columbia found that holding weight 10% below its usual level lowered T3, T4 and leptin.^[10] Lower thyroid hormone at a lower weight is an adaptation, not thyroid disease.

Smaller meals make less heat. Digesting food produces heat, a small effect called diet-induced thermogenesis. In a 2000 crossover study of 20 healthy young men, an infusion of GLP-1 cut the heat produced after a fixed breakfast by 47% compared with saline, which the authors attributed to slower absorption of the meal.^[11] Someone eating far less on a GLP-1 also generates less of that heat across the day. Whether either effect is large enough to feel has not been studied.

Fat insulates, a little. In an NIH study that cooled men in a calorimetry room, men with obesity had more insulation from fat but did not tolerate cold any better: both groups reached their coldest bearable temperature at similar skin temperatures.^[12] In 110 young adults, women with more body fat and lean mass took longer to start shivering when cooled; men showed no such link.^[13] Losing a lot of fat could plausibly make some people, women especially, feel the cold sooner. No study has tested that after GLP-1 weight loss.

Metabolic rate itself is a separate question with better data. The studies that measured it on semaglutide and tirzepatide found the drop roughly matched the weight lost; the details are in our metabolism review.

Does the drug itself change body temperature?

In people, nobody knows, because nobody has measured it. The direct evidence on GLP-1 drugs and temperature is almost entirely from rodents, and it does not point one way.

The rat studies conflict. One found liraglutide cooled rats; another found semaglutide kept dieting rats warmer than diet alone. Brown fat, the tissue that burns energy to make heat, lit up more on scans after exenatide in one small human study but not after liraglutide in another. A brown fat scan reading is not body temperature, and rodents rely on brown fat for warmth far more than adults do. None of this shows that a GLP-1 drug makes a person colder or warmer.

Night sweats: check blood sugar first

The one place sweating appears on these labels is the list of low-blood-sugar warning signs. The labels tie the risk to other diabetes medicines:

Your risk for getting low blood sugar may be higher if you use OZEMPIC with another medicine that can cause low blood sugar, such as a sulfonylurea or insulin.

— Ozempic Medication Guide, DailyMed

Mounjaro and Zepbound carry the same warning, naming the same two drug types.^[3][4] The sweating, shakiness, hunger and fast heartbeat that come with a low can happen at any hour. Waking up drenched, with a headache or a racing heart, is worth checking with a glucose meter if you take insulin or a sulfonylurea such as glipizide or glimepiride. That is an inference from the label’s symptom list; no GLP-1 label uses the words “night sweats.” Who is actually at risk is covered in GLP-1 low blood sugar risk.

Counterfeit pens are the exception for people without diabetes. Dutch doctors reported two people with neither diabetes nor obesity who injected semaglutide bought without a prescription and arrived in a coma with severe low blood sugar, low potassium and a low body temperature. The product contained insulin. The authors note that semaglutide alone does not cause meaningful hypoglycemia in healthy people.^[21] Sudden sweating, shaking or confusion after a dose from an unofficial source is an emergency.

Most night sweats have nothing to do with any of this. In a survey of 2,267 adults in US primary care, 41% said they had had night sweats in the past month, most never mentioned them to a doctor, and they were linked to hot flashes, panic attacks, sleep problems, antidepressants including SSRIs, higher weight and, in men, alcohol.^[22] A systematic review concluded that night sweats are a nonspecific symptom, linked to menopause, cancers, autoimmune disease and infections, but usually found in people with none of them.^[23] Many people starting a GLP-1 are women in their 40s and 50s, the ages when menopausal hot flashes and night sweats peak, so timing alone can mislead.

When the thyroid is the real cause

Feeling cold is one of the classic symptoms of an underactive thyroid, alongside tiredness, lethargy, weight gain, constipation and dry skin.^[24] Those symptoms overlap with what people blame on a GLP-1, and a Danish study of 140 newly diagnosed patients found no single symptom reliable enough to rule the condition in or out. Its authors’ advice: even minor suspicion should lead to a blood test.^[25]

A 2026 case report shows how the two can tangle. A 54-year-old woman developed fatigue and new cold intolerance after losing 22 kg in four months on semaglutide. Her T3 was low with a normal TSH, a pattern called euthyroid sick syndrome that reflects the body’s response to rapid weight loss rather than thyroid disease. Her symptoms resolved as her weight stabilized and her eating improved, without thyroid medicine.^[26] One case proves nothing about frequency. It does show why a thyroid panel, read by someone who knows the patient is losing weight fast, is a reasonable step.

The opposite problem produces sweating. If you take levothyroxine and lose a lot of weight, your old dose can become too high. The Synthroid label lists heat intolerance, fever and excessive sweating among the effects of too much thyroid hormone.^[27] A study of Medicare patients found that thyroid testing did not increase after people started a GLP-1, as described in the thyroid test nobody reordered. How the dose interacts with these drugs is set out in levothyroxine and a GLP-1.

Cold all over versus cold hands and feet

Feeling chilled through is not the same as hands and feet that are cold, tingling or burning. The Wegovy label does list a group of altered skin sensations, called dysesthesia, that includes tingling, burning and sensitive skin, and it becomes more common at higher doses: 22% on the 7.2 mg injection against 6% on 2.4 mg and 0.3% on placebo.^[2] Those are nerve sensations, not body temperature. They are covered in Ozempic and your hands and feet. A racing heart with sweating has its own guide in GLP-1 heart rate and palpitations.

When feeling cold or sweaty needs a doctor

• Sweating with shakiness, confusion, hunger or a racing heart, especially when insulin or a sulfonylurea is part of your treatment. Check your glucose and treat a low as your diabetes plan says.^[1]
• Any of those symptoms after a dose bought outside a pharmacy. Counterfeit semaglutide containing insulin has put people in a coma.^[21]
• Fever with pain in the upper right abdomen, yellow skin or eyes, or pale stools. The labels list these together as gallbladder warning signs.^[1][3]
• Drenching night sweats with fever, or weight loss beyond what your dose explains. Night sweats are linked to infections and cancers as well as harmless causes.^[23] On a GLP-1, weight loss is expected, which makes it easy to miss when it is not the drug. Tell your prescriber how fast you are losing and whether that changed.
• Cold intolerance with worsening fatigue, constipation, dry skin or hair loss, or sweating and heat intolerance if you take levothyroxine. Ask for a thyroid test.^[25][27]
• Shivering, drowsiness or confusion with a low measured temperature. That is not ordinary chilliness and needs urgent care.

If none of those apply and you simply feel colder than you used to, the evidence suggests that is the cost of eating less and weighing less. Regular meals with enough protein, layers and staying active are the practical answers, and the feeling is worth mentioning at your next appointment rather than ignoring. Tiredness that comes with it is covered in what causes fatigue on a GLP-1.