Can Mounjaro cause hair loss? Hair thinning side effects explained
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Can Mounjaro cause hair loss? Learn the facts about tirzepatide and hair thinning – and how to manage it.
Have you noticed extra hairs in the shower or your hairbrush since starting Mounjaro (tirzepatide)? You're not alone.
Hair thinning and shedding are listed as side effects of Mounjaro. However, evidence points to quick weight loss as the cause, rather than direct damage to your hair.
Let's unpack what studies say about hair changes with Mounjaro, why rapid weight loss can trigger shedding and what you can do about it.
Is hair loss a known side effect of tirzepatide?
Yes, but context matters.
In pooled obesity trials, reports of hair shedding with tirzepatide were linked to weight loss and were more common in women than men:
| People taking tirzepatide | People taking a placebo (dummy drug) |
|---|---|
| 7.1% of women experienced hair loss | 1.3% of women experienced hair loss |
| 0.5% of men experienced hair loss | 0% of men experienced hair loss |
Interestingly, no one on tirzepatide stopped treatment because of hair loss, while one person on placebo did.
A similar pattern appears with semaglutide (Wegovy). In EU product information for Wegovy, hair loss was reported in 2.5% of patients on semaglutide versus 1% on placebo. Most cases were mild and occurred more often in people who lost at least 20% of their body weight.
Why can weight loss trigger shedding?
The important thing to know is that Mounjaro does not directly cause hair loss. Instead, hair shedding occurs because of changes in the body triggered by weight loss.
The most likely cause is telogen effluvium. This condition can occur after a significant stress on the body, causing more hairs than usual to move into a resting phase. A few months later, this will cause extra shedding.
Common triggers include illness, big life changes and rapid weight loss or strict dieting. As your weight and nutrition settle, shedding usually eases, and your hair should grow back.
In other words, hair loss with tirzepatide is usually temporary and linked to the stress your body is under. It's not because of any lasting damage to your hair follicles.
Practical steps to lower the risk
- Aim for steady weight loss and avoid crash dieting.
- Prioritise protein and include iron, zinc and vitamin D-rich foods.
- Keep stress in check and make sure you get enough sleep.
- Be gentle with your hair care routine.
When to seek medical advice
Book an appointment with your healthcare provider or talk to the SemaPen team if:
- You're worried about hair loss, or the shedding hasn't eased after a few months
- You notice patchy bald areas or a quickly widening parting
- You experience scalp pain, itching, scaling or redness
- Hair loss comes with other symptoms such as fatigue, rapid and unexplained weight change or changes to your menstrual cycle
Your healthcare team can check for treatable causes (such as low iron or thyroid problems) and advise on next steps.
SemaPen: a safe, steady way to use Mounjaro
At SemaPen, we prescribe Mounjaro within a structured medical weight loss plan. That means you're supported from day one.
You start with an online consultation reviewed by a UK-registered prescriber. If we feel our treatment is safe and appropriate for you, we provide:
- Ongoing clinical monitoring to keep your rate of weight loss steady
- Nutrition guidance so that protein and key micronutrients are covered
- Smart scale integration and regular check-ins
- Clear safety information and quick access to help if you encounter side effects
Want to find out if our weight loss programmes could help you? You can get started today by taking our simple online consultation.
Sources
1. Eli Lilly and Company (2023) United States prescribing information: Zepbound. 4.0-ZEP-0000-PEN-IFU-YYYYMMDD. Retrieved from https://www.accessdata.fda.gov/drugsatfda_docs/label/2023/217806s000lbl.pdf
2. European Medicines Agency (2025) European Public Assessment Report (EPAR) for Wegovy. Retrieved from https://www.ema.europa.eu/en/documents/product-information/wegovy-epar-product-information_en.pdf
This article was reviewed and approved by Alice Fletcher, Lead Bariatric Dietitian, on 1 September 2025.
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