Does Mounjaro cause hair loss?

Mounjaro (tirzepatide) is linked to hair loss: the NHS lists hair loss among its common side effects,¹ and in a 2026 BMJ study of adults with type 2 diabetes, people starting a GLP-1 medicine had a 37% higher rate of hair loss than those starting an SGLT-2 inhibitor and a 68% higher rate than those starting a DPP-4 inhibitor, although the absolute risk was low.² The shedding was non-scarring, so the follicles stay intact and the hair can grow back.²

Sources checked on 29 October 2026.

Hair is one chapter of living well on Mounjaro, alongside Mounjaro face, tiredness, what happens when you stop and side effects in women.

Does Mounjaro cause hair loss?

It is associated with it, rather than acting on the follicle directly. The BMJ study used US health records from 2019 to 2024 to compare adults with type 2 diabetes who started a GLP-1 receptor agonist, the class tirzepatide belongs to, with adults who started other diabetes medicines: about 27,000 adults in the SGLT-2 inhibitor comparison and 23,000 in the DPP-4 inhibitor comparison. After adjustment, the GLP-1 group had a hazard ratio of 1.37 for alopecia against SGLT-2 inhibitors and 1.68 against DPP-4 inhibitors, and the link was specific to non-scarring hair loss.² These were people with type 2 diabetes, so the figures do not transfer one-to-one to everyone on Mounjaro for weight loss.

A 2026 systematic review of 24 studies found the same pattern: semaglutide and tirzepatide had the highest reported rates of hair loss among GLP-1 medicines, tirzepatide was most often linked to telogen effluvium, women were disproportionately affected, and rapid weight loss emerged as the likely contributor.³ The evidence points less at the medicine than at what it does: a large, fast drop in weight and calories.

How common is it?

The firmest figure is in the product information: across the pooled weight-management trials, hair loss was reported by 4.9% of people on tirzepatide against 1.0% on placebo, mostly mild, and most recovered while continuing treatment.¹³ The NHS lists it as common,¹ the BMJ authors call the absolute risk low,² and the review did not pool a rate.³ Bariatric surgery, the other route to very fast weight loss, gives a comparison: across 18 studies of 2,538 patients, 57% reported hair loss, most often younger women and those with low zinc, folate or ferritin.⁴

Why does rapid weight loss trigger hair shedding?

The mechanism is telogen effluvium. A follicle grows a hair for around four years, rests for around four months, then sheds it as a new hair pushes through.⁵ A significant physical stressor can tip a large share of growing hairs into the resting phase at once, and the recognised triggers include crash dieting, low protein intake and iron deficiency as well as illness, surgery and childbirth.^{5, 6}

When does it start, and does it grow back?

Telogen effluvium lags its trigger: diffuse shedding appears around three to four months after the event.⁷ Because the follicles are intact, it has a high rate of remission once the trigger settles,⁶ but hair that re-enters the growth phase takes months to show as length, so judge the result over months, not weeks.

Is Mounjaro hair loss permanent in women?

For hair loss caused by rapid weight loss, no. Telogen effluvium is non-scarring and usually remits.⁶ Women are most often affected,³ and thyroid conditions, hormonal changes and iron deficiency produce a similar diffuse thinning, so see your GP if you are unsure, particularly with fatigue, cold intolerance or irregular periods.

What vitamins and nutrients help with hair loss on Mounjaro?

Three nutrients carry an authorised UK health claim for hair: biotin, zinc and selenium each contribute to the maintenance of normal hair.⁸ Iron and protein have no claim but matter in practice.

Biotin contributes to the maintenance of normal hair.⁸ True deficiency is uncommon, and high-dose biotin can distort blood tests: in a six-person study, 10 mg a day for seven days skewed 9 of 23 biotin-based assays, including thyroid hormones and ferritin.⁹ Tell whoever takes your blood that you take it.

Zinc contributes to the maintenance of normal hair, skin and nails.⁸ Appetite suppression crowds out zinc-rich foods (meat, shellfish, legumes, seeds), and low zinc was tied to shedding after bariatric surgery.⁴ See signs of zinc deficiency.

Iron is not one to supplement on spec. Low ferritin was associated with hair loss after bariatric surgery,⁴ and iron deficiency has been linked to telogen effluvium and diffuse hair loss in several studies of women, though not all,¹⁰ while too much iron causes overload. Test ferritin before supplementing.¹⁰

Protein is the lever most within your control. Hair is built from keratin, a protein, and low protein intake is a recognised trigger of telogen effluvium.⁵ For B12, vitamin D, iron and magnesium, see which vitamins to take on Mounjaro.

Does collagen help with hair loss on Mounjaro?

Collagen is a protein, digested to amino acids like any other. Most collagen trials measured skin: across 26 randomised trials in 1,721 people, hydrolysed collagen improved skin hydration and elasticity against placebo.¹¹ One 24-week trial by researchers at a health-food company, in 114 women with self-reported thinning, recorded thicker hair shafts on collagen peptides than on placebo.¹² None involved people on a GLP-1 medicine, and collagen has no authorised UK health claim. A collagen powder counts in full towards your protein for the day, and protein is the nutrient the hair cycle depends on most during fast weight loss.⁵ See collagen for hair and nails, does zinc help with hair loss and what you can notice after taking collagen.

How to minimise hair shedding on Mounjaro

• Talk to your prescriber if weight is dropping very fast. A steadier pace is easier on the hair cycle.³
• Prioritise protein at each meal, since low protein intake is itself a trigger.⁵
• Don't guess on supplements. A blood test for ferritin, vitamin D, B12 and thyroid function shows what is low.
• Be gentle with your hair while it sheds. Less heat, no tight styles or harsh chemical treatments.
• Give it time. With a three-to-four-month lag,⁷ today's changes show months from now.

When to see your GP

Book an appointment if the shedding is severe, carries on well after your weight has settled, comes with patchy bald spots, scalp pain, redness or scarring, or arrives with persistent fatigue, brittle nails or a change in your periods: those patterns point to something else. Your GP may suggest a full blood count, ferritin, vitamin B12 and folate, vitamin D and thyroid function tests.

What we don't know

Whether tirzepatide adds anything beyond the speed of weight loss: the BMJ comparison was with other diabetes medicines, not with equal weight loss by another route, and the 2026 review calls for prospective trials to establish causality.²³ How long it lasts on continued treatment has not been timed, and no trial has tested whether protein, iron or zinc intake shortens it in this group.

Frequently asked questions

How do I stop hair loss while on Mounjaro?

Not overnight: today's shedding reflects what your body went through three to four months ago.⁷ The levers are a steadier pace of loss, enough protein and calories, correcting any confirmed deficiency, and gentle handling.

What vitamins are good for Mounjaro hair loss?

Biotin, zinc and selenium carry the authorised claim for the maintenance of normal hair.⁸ Iron matters when a blood test shows ferritin is low; protein matters for everyone whose appetite has fallen.

Does hair grow back after stopping Mounjaro?

If the cause is telogen effluvium, hair usually grows back once the trigger settles, whether or not you stay on Mounjaro,⁶ and takes months to become visible.

How long does Mounjaro hair loss last?

Shedding typically begins three to four months after the trigger⁷ and eases once weight and eating stabilise.

How common is hair loss on Mounjaro?

Common enough for the NHS to list it:¹ 4.9% of people on tirzepatide against 1.0% on placebo in the pooled weight-management trials,¹³ and a 37% to 68% higher rate of alopecia in GLP-1 users in the 2026 BMJ study, with a low absolute risk.²

Sources

1. NHS. Tirzepatide. Page last reviewed 15 May 2026. nhs.uk/medicines/tirzepatide.
2. Tang H, et al. Risk of hair loss associated with glucagon-like peptide-1 receptor agonists in adults with type 2 diabetes: target trial emulation. BMJ, 2026. Target trial emulation in US health records, 2019 to 2024; two comparisons of 27,225 and 23,202 adults with type 2 diabetes; hazard ratios 1.37 and 1.68; US National Institutes of Health funding. PubMed 42486607.
3. Gupta AK, et al. GLP-1 therapies and hair loss: a systematic review of current evidence and implications for counseling. Science Progress, 2026. Systematic review, 24 studies; one author reports trial grants from pharmaceutical companies including the maker of tirzepatide. PubMed 41998799.
4. Zhang W, et al. Hair loss after metabolic and bariatric surgery: a systematic review and meta-analysis. Obesity Surgery, 2021. Pooled analysis of 18 studies, 2,538 patients; incidence 57%; no competing interests declared. PubMed 33675022.
5. Hughes EC, Syed HA, Saleh D. Telogen effluvium. StatPearls, 2024. Reference text; authors declare no relevant financial relationships. PubMed 28613598.
6. Chien Yin GO, et al. Telogen effluvium: a review of the science and current obstacles. Journal of Dermatological Science, 2021. Narrative review; no funding or conflicts listed on PubMed. PubMed 33541773.
7. Malkud S. Telogen effluvium: a review. Journal of Clinical and Diagnostic Research, 2015. Narrative review; funding not stated on PubMed. PubMed 26500992.
8. Department of Health and Social Care. Great Britain nutrition and health claims (NHC) register, last updated 19 May 2026. gov.uk.
9. Li D, et al. Association of biotin ingestion with performance of hormone and nonhormone assays in healthy adults. JAMA, 2017. Non-randomised crossover study, 6 adults, 7 days; US government funding, authors report diagnostics-company fees. PubMed 28973622.
10. Trost LB, Bergfeld WF, Calogeras E. The diagnosis and treatment of iron deficiency and its potential relationship to hair loss. Journal of the American Academy of Dermatology, 2006. Narrative review; funding not stated on PubMed. PubMed 16635664.
11. Pu SY, et al. Effects of oral collagen for skin anti-aging: a systematic review and meta-analysis. Nutrients, 2023. Pooled analysis of 26 randomised trials, 1,721 people; authors declare no conflict of interest. PubMed 37432180.
12. Hwang S, et al. Low-molecular-weight collagen peptide supplementation improves cellulite severity, skin elasticity, and hair shaft diameter: a clinical study with pharmacokinetic evaluation. Journal of Medicinal Food, 2026. Randomised placebo-controlled trial, 114 women, 24 weeks; authors employed by a health-food company. PubMed 41788055.
13. Tirzepatide Summary of Product Characteristics, section 4.8 (hair loss 4.9% against 1.0% on placebo in pooled SURMOUNT-1, -2 and -3), electronic medicines compendium, date of revision of the text 29 August 2026. medicines.org.uk.

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General information, not medical advice. Mounjaro is a prescription medicine: follow your prescriber's instructions, and speak to your GP or pharmacist about hair loss or before starting a supplement, especially if you take other medicines or have a health condition.