Encyclopedia entry

GLP-1 medications and hair loss

Hair loss is a reported but still emerging adverse effect of GLP-1 weight-loss medication such as semaglutide (Wegovy) and tirzepatide (Mounjaro). The pattern described most often in the literature is telogen effluvium, a temporary shedding triggered by rapid weight loss and the physiological stress that comes with it, rather than direct damage from the drug. Reported rates in trials are low and most cases are described as temporary. The evidence base is limited and under investigation, so anyone concerned about hair shedding should raise it with their prescriber. This page is editorial commentary, not clinical advice.

What the literature actually says

• · A 2025 scoping review of nine studies found alopecia reported across semaglutide, liraglutide, tirzepatide and dulaglutide, with telogen effluvium and androgenetic alopecia the most frequently identified subtypes. Most studies lacked dermatological confirmation, so the association is described as plausible but not yet well characterised.
• · A 2025 retrospective cohort in the Journal of the American Academy of Dermatology examined GLP-1 use and hair loss signals, adding to the pharmacovigilance picture rather than proving causation.
• · A 2024 dermatology commentary noted that despite widespread theories, direct clinical evidence linking GLP-1 medicines to hair loss remained sparse and called for monitoring.
• · Across spontaneous reporting systems, more than a thousand hair-loss reports have been logged, which signals a pattern worth studying but does not establish how common or how drug-specific it is.

Why rapid weight loss is the likely driver

Telogen effluvium is a recognised response to any significant physiological stress, including rapid weight loss, low energy intake and reduced protein, regardless of the cause. Because GLP-1 medication suppresses appetite and drives fast weight loss, the same shedding seen after illness, surgery or crash dieting can appear a few months in. This is why the shedding is usually described as temporary and self-limiting once weight stabilises and nutrition is adequate. It is also why maintaining protein intake matters during treatment.

Related reading on nutrition during rapid loss: protein intake on GLP-1.

What to do if you notice shedding

• · Raise it with your prescriber. They can check for other causes such as thyroid changes, iron or other deficiencies, which are common and treatable.
• · Keep protein and overall nutrition adequate during rapid weight loss.
• · You can report a suspected reaction to the MHRA through the Yellow Card scheme.
• · Do not stop a prescribed medication without speaking to the prescriber first.

Frequently asked questions

References

• · Rojas Lopez RF, et al. Alopecia as an Emerging Adverse Effect Associated With GLP-1 Receptor Agonists for Weight Loss: A Scoping Review. Cureus. 2025. PMID 40951222.
• · Burke O, et al. GLP-1 receptor agonist medications and hair loss: a retrospective cohort study. J Am Acad Dermatol. 2025. PMID 39863171.
• · Desai DD, et al. GLP-1 agonists and hair loss: a call for further investigation. Int J Dermatol. 2024. PMID 38741261.

Related: protein on GLP-1 · muscle preservation · Mounjaro side effects.