Independent UK medicine guidance
Mounjaro and hair loss
Hair loss is a recognised common side effect of Mounjaro when it is used for weight management.
In pooled SURMOUNT weight-management studies, hair loss was reported by 4.9% of participants taking tirzepatide, compared with 1% taking a placebo. The reported cases were mainly mild, most participants recovered while continuing treatment and nobody taking tirzepatide left the studies because of hair loss.
That is reassuring, but it does not make hair shedding any less distressing when it happens.
Is it the medicine or the weight loss?
The studies establish an association with tirzepatide treatment, but they do not prove that the medicine directly damages hair follicles.
Significant weight loss, a sharp reduction in calorie intake, illness and nutritional deficiencies can trigger a temporary form of shedding called telogen effluvium. More hairs than usual enter their resting phase and are shed several weeks or months later. This usually causes diffuse thinning across the scalp rather than completely bald patches.
What should you check?
Consider whether you have also experienced:
- Very rapid weight loss
- Difficulty eating enough food
- Repeated vomiting or diarrhoea
- Low protein intake
- Heavy periods
- Recent illness, surgery or emotional stress
- Symptoms of thyroid disease or anaemia
- A new medicine or supplement
Mounjaro should support sustainable weight management, not prevent you from meeting your basic nutritional needs.
What may help?
Prioritise a balanced diet containing regular sources of protein, iron, zinc and other essential nutrients. Avoid extreme calorie restriction and do not automatically move to a higher dose if you can barely eat.
Do not start high-dose iron, zinc or other supplements on the assumption that you are deficient. Excessive supplementation can cause harm and will not correct a problem that is not present.
Speak to your prescriber or GP if the shedding is significant. Depending on your symptoms and medical history, they may consider blood tests for anaemia, iron deficiency, thyroid problems or other causes.
When should you see a doctor?
Arrange an assessment if:
- Hair is coming out in patches
- Your scalp is painful, inflamed, scaly or scarred
- You are losing eyebrow or body hair
- Shedding is severe or continues for several months
- You have unexplained tiredness, palpitations or breathlessness
- Your food intake has become extremely limited
Hair loss does not automatically mean you must stop Mounjaro. The decision should consider its severity, your nutrition, the rate of weight loss and the benefits you are receiving from treatment.
Related Monj guides
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