How does Mounjaro affect energy levels?
Mounjaro can affect energy levels, and some people notice tiredness or low energy—especially in the first weeks or after a dose increase—as the body adjusts to eating less and changes in digestion and hormones that influence appetite and blood sugar. Fatigue is reported in real-world UK guidance and patient advice, and while not always highlighted in every trial summary, it is recognised by multiple UK online doctor and pharmacy resources as a possible effect. Tiredness can also be linked to indirect factors like nausea, vomiting or diarrhoea leading to dehydration or electrolyte imbalance, or—if used with certain diabetes medicines—episodes of low blood sugar. For most people, these effects are temporary and improve with time, good hydration, balanced nutrition, steady activity, and support from a clinician if symptoms are persistent or severe.
- Feeling more tired can occur on Mounjaro, often early on or after dose increases, and usually improves as the body adapts.
- Eating less, changes in gut hormones, and slower digestion can reduce available energy and contribute to fatigue.
- Nausea, vomiting, or diarrhoea may cause dehydration/electrolyte loss, which can worsen tiredness.
- Low blood sugar is uncommon unless combined with certain diabetes medicines, but if present it can cause fatigue and needs medical advice.
- UK pharmacy/online doctor guidance recommends sleep hygiene, hydration, balanced meals, and gentle activity to support energy.
- Seek medical help if tiredness is severe, persistent, or accompanied by warning signs like dizziness, confusion, or recurrent low blood sugar symptoms.