Why Do I Feel Cold on Mounjaro — and What Else Might You Notice?

Several physical changes are commonly reported by people taking Mounjaro, and most trace back to a handful of overlapping reasons: the medicine's effect on appetite, calorie intake, digestion speed, and the body's gradual adjustment to weight change.

Feeling cold

A noticeable sensitivity to cold is frequently reported by people losing weight on a GLP-1 or dual GIP/GLP-1 medicine like Mounjaro. When the body loses fat, it loses some of its natural insulation — and a reduced calorie intake means less energy being burned as heat. These two factors together can leave many people feeling colder than usual, especially in their hands and feet. This is a commonly observed pattern during significant weight change and is not unique to Mounjaro. If the cold feeling is extreme, accompanies other worrying symptoms, or you are concerned, speak to your prescriber or doctor rather than assuming it is routine.

Feeling tired or low in energy

Fatigue is one of the more frequently reported experiences, particularly around dose increases or in the early weeks on the medicine. Eating less overall — which many people do as appetite reduces — means the body has less fuel available, and that can translate into lower energy levels day to day. Many people find this eases as their body adjusts. For a deeper look at this pattern, common experiences on Mounjaro covers what people typically notice across their journey.

Nausea and feeling sick

Nausea is one of the most widely reported side effects of Mounjaro. Tirzepatide acts on GLP-1 receptors that influence how quickly the stomach empties, and slowed gastric emptying can cause feelings of nausea, fullness, or sickness — particularly after eating too quickly or in larger portions. For most people it is most pronounced in the days following a dose or a dose increase, and it often settles over time. You can read more about feeling cold and other physical changes on Mounjaro for additional context.

Bloating and digestive discomfort

Because Mounjaro slows the movement of food through the digestive system, bloating, indigestion, and a sense of fullness are commonly reported. Eating smaller amounts more slowly, and choosing foods that are easier to digest, is something many people find helpful — though any dietary changes should suit your own body and situation.

Dizziness

Some people report dizziness, particularly if they are eating or drinking significantly less than before. Staying well hydrated and not skipping meals entirely (even if appetite is low) is something many people on GLP-1 medicines find makes a difference. If dizziness is frequent, severe, or accompanied by other symptoms, contact your healthcare professional promptly — do not try to self-diagnose the cause. If you are also noticing persistent hunger alongside these effects, why you might still feel hungry on Mounjaro is worth exploring.

One of the most useful things you can do when you notice physical changes like these is to record them consistently, so you can spot patterns and have an informed conversation with your prescriber.

GLP Trackr's side-effect and wellbeing tracker is built exactly for this. You can log symptoms — cold sensitivity, fatigue, nausea, bloating, dizziness — each day alongside your dose date, so over time you can see whether symptoms cluster around injection day, improve as weeks pass, or shift with dose changes. That kind of pattern is genuinely useful to bring to a prescriber appointment, and the app's doctor report feature lets you share a clear summary of your journey without having to reconstruct it from memory.

The daily check-in also lets you record energy levels, mood, sleep, and food noise in under a minute — building a picture of how your body is adjusting week by week, not just what the scale says.

For a broader overview of the Mounjaro journey and what to expect, visit the Mounjaro guide hub.

A note on safety: GLP Trackr helps you record how you feel so you can discuss it with your prescriber — it is not a substitute for their guidance. If any symptom is severe, persistent, or worrying, contact your healthcare professional promptly. Side effects can also be reported to your national reporting scheme (such as the UK's Yellow Card scheme) and to your prescriber.

Log your symptoms, spot your patterns, and walk into your next appointment prepared. GLP Trackr is free to try for 7 days — available on the App Store and Google Play.