Side effects & safety

Does Zepbound Cause Hair Loss? What the Label and the Studies Actually Say

Hair loss is a listed Zepbound side effect with real numbers behind it. Here is how common it was in the trials, why it affected women far more than men, what the newest population studies found, and why researchers think rapid weight loss is doing most of the work.

Last verified September 14, 2026·8 sources cited·Mounjaro Zepbound

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Short answer: hair loss is a listed side effect of Zepbound with real numbers behind it, it affected women far more often than men in the trials, and the label itself links it to the weight loss rather than to the drug acting on your hair.

That is a more specific answer than most GLP-1 drugs can give, because Zepbound is one of the few whose label actually quantifies it. Here is what the numbers are and what the research says about why.

Nothing here is medical advice. If you are shedding enough hair to worry you, a healthcare provider is the right place to take it, partly because several other causes of hair loss are treatable and worth ruling out.

What does the Zepbound label say about hair loss?

Hair loss appears twice in the Zepbound prescribing information [1].

First, it is named in the Highlights section among the adverse reactions reported in at least 5% of patients — the short list that also includes nausea, diarrhea, vomiting, constipation, abdominal pain, indigestion, injection site reactions, fatigue, hypersensitivity reactions, burping and reflux.

Second, it appears in the main adverse reaction table from the two 72-week placebo-controlled weight-reduction trials [1]:

	Placebo	Zepbound 5 mg	Zepbound 10 mg	Zepbound 15 mg
Hair loss	1%	5%	4%	5%

Two details from the label make this more useful than the bare percentages.

It is overwhelmingly a finding in women. The label reports 7.1% of women on Zepbound versus 0.5% of men. On placebo, 1.3% of women and 0% of men [1].

Nobody stopped the drug for it. No Zepbound-treated patient discontinued because of hair loss. One placebo-treated patient did [1].

And the sentence that does most of the explanatory work: the label states that hair loss adverse reactions were associated with weight reduction [1]. That is the FDA-approved labeling pointing at the weight loss, not the molecule, as the likely driver.

What about Mounjaro?

Same drug, different label treatment.

On the Mounjaro label, alopecia appears only in Section 6.2, Postmarketing Experience, under Skin and Subcutaneous Tissue Disorders [2]. That section collects reports that came in voluntarily after approval, and the label states that because they come from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship.

So there is no Mounjaro hair loss percentage. That is a difference in what the two trial programs recorded, not evidence that Mounjaro is gentler on hair. Mounjaro’s trials were in people with type 2 diabetes, who lost less weight, over different durations, with different adverse event collection.

If the label’s own theory is right — that the hair loss tracks the weight loss — then you would expect to see more of it in a program where people lost 20% of their body weight than in one where they lost considerably less.

Why does it happen?

The mechanism described consistently in published reviews is telogen effluvium [6].

Hair grows in cycles. At any moment most of your follicles are in an active growing phase and a minority are in a resting phase, after which the hair sheds. Telogen effluvium is what happens when a physical stressor pushes an unusually large share of follicles into the resting phase at once. Two to four months later, they all shed together.

The classic triggers are the ones you would expect: major illness, surgery, childbirth, high fever, severe emotional stress — and rapid weight loss with reduced calorie intake.

Rapid weight loss on a GLP-1 drug hits several of those at once:

Sharply lower calorie intake. This is how the drug works.
Lower protein intake, which often falls further than total calories when appetite drops.
Lower micronutrient intake, including iron and zinc, both of which matter for hair.
Loss of lean mass, which is part of any substantial weight loss. In the SURMOUNT-1 body composition substudy, about a quarter of the weight lost on tirzepatide was lean mass — the same proportion as in the placebo group [8].

Nothing in the published literature establishes that tirzepatide acts directly on hair follicles. A 2026 review summarizing the evidence concluded that the strongest signals are for semaglutide and tirzepatide as a pair, and that causality has not been established [6].

The timing pattern fits the telogen effluvium story too. Shedding that starts two to four months after a big change, peaks, and then settles is the classic shape. Shedding that starts the week you take your first injection is less likely to be this.

What do the population studies show?

This is where the picture gets genuinely muddy, and it is worth seeing why rather than being handed a single number.

The BMJ target trial emulation (July 2026) used Penn Medicine electronic health records to compare adults with type 2 diabetes starting a GLP-1 receptor agonist against those starting other diabetes drugs, over a mean 2.7 years. GLP-1 initiators had a higher risk of alopecia than SGLT2 inhibitor initiators (hazard ratio 1.37, 95% CI 1.08 to 1.73) and than DPP-4 inhibitor initiators (hazard ratio 1.68, 95% CI 1.28 to 2.20). The association was specific to non-scarring alopecia, and the authors note the absolute risk is low — roughly 7 cases per 1,000 person-years against 4 to 5 in the comparator groups [4]. This is a class-level result: it does not separate tirzepatide from the rest of the class, so it cannot tell you anything about Zepbound specifically.

A TriNetX analysis (2026) in 547,993 matched adults found GLP-1 users had higher 12-month odds of telogen effluvium (adjusted odds ratio 1.76), androgenetic alopecia (1.64) and non-scarring hair loss overall (1.40) [7].

A 2025 reporting-database analysis put the reporting odds ratio for alopecia at 2.46 for semaglutide and 1.73 for tirzepatide [6].

So far, consistent. Then:

A 2026 reporting-database analysis that adjusted for confounders found semaglutide positively associated with alopecia (adjusted reporting odds ratio 1.23) but tirzepatide negatively associated (0.78, 95% CI 0.72 to 0.85) — meaning hair loss was reported less often than expected for tirzepatide [5].

An All of Us database analysis found no significant increase for tirzepatide across any alopecia subtype [6].

Why do these disagree? Three reasons worth understanding, because they apply to most drug safety headlines:

The drugs get pooled. Several of these studies group all GLP-1 drugs into one exposure. If semaglutide drives the association, tirzepatide inherits it in the results without having earned it.
Reporting data are not incidence data. Spontaneous report databases measure how often something gets reported. Media coverage changes reporting rates; it does not change biology.
The comparator matters enormously. People starting an SGLT2 inhibitor are not losing 20% of their body weight. If weight loss is the cause, then any comparison against a drug that does not cause weight loss will show a difference, and that difference is not a statement about the molecule.

The one place the pooling problem does not apply is the head-to-head trial. In SURMOUNT-5, alopecia was reported by 8.3% on tirzepatide and 6.1% on semaglutide [3]. That is a small gap, in a 751-person trial, using adverse event reporting rather than dermatologist assessment, in a study not designed to measure hair.

How long does it last?

Published reviews describe telogen effluvium as typically temporary, and note that at least some reported cases have reversed [6].

That is as far as the evidence goes, and it is worth being clear about the gap. There is no published long-term follow-up study tracking hair regrowth specifically in people who took tirzepatide. The trials recorded whether hair loss was reported as an adverse event; they did not follow hair density over time after the event, and they did not follow people who stopped the drug.

What can be said from the trial data is that the reported rate did not climb with dose (5%, 4%, 5%) and did not lead anyone to stop the drug [1]. Neither of those is a statement about recovery.

What is actually known, and what is not?

Reasonably well established:

Hair loss occurs in roughly 4% to 5% of people on Zepbound in trials, versus 1% on placebo [1].
It is far more common in women than men in that data: 7.1% versus 0.5% [1].
Non-scarring hair loss is more common among GLP-1 users than among users of comparison diabetes drugs, in more than one large population study [4][7].
The FDA-approved label attributes it to weight reduction [1].

Not established:

That tirzepatide acts directly on the hair follicle.
That tirzepatide causes more or less hair loss than semaglutide.
That the hair loss is permanent, or that it reliably reverses.
Whether any particular intervention changes the outcome in this specific setting.

Under evaluation:

The authors of the BMJ study state that the FDA has indicated it is evaluating hair loss as a potential safety signal for the class [4]. As of September 14, 2026, no label change had followed.

What should you raise with a healthcare provider?

This is a page about evidence, not a treatment plan, and nothing here should substitute for an individual assessment. But there are a few things worth knowing before that appointment.

Hair loss has many causes that have nothing to do with a weight-loss drug, and several of them are treatable: thyroid disease, iron deficiency, other medications, and androgenetic alopecia that was already progressing. The TriNetX study finding elevated odds of androgenetic alopecia, not just telogen effluvium, is a reminder that more than one thing can be happening at once [7].

Rapid weight loss with reduced protein and micronutrient intake is the mechanism the literature keeps pointing to [6][8]. Whether and how to address that — nutritional intake, how fast weight is coming off, whether any blood work is warranted — is a conversation with a clinician, not something to sort out from a label table.

And dose changes are prescriber decisions. The label does not suggest stopping or reducing the dose for hair loss, and no one in the trials stopped for it.

Sources

Questions people ask

Is hair loss an official Zepbound side effect?

Yes. Hair loss is listed in the Zepbound prescribing information among the adverse reactions reported in at least 5% of patients. In the pivotal trials it occurred in 5%, 4% and 5% of people at 5, 10 and 15 mg, compared with 1% on placebo [1].

How common is hair loss on Zepbound in women?

The label breaks it out by sex: 7.1% of women on Zepbound reported hair loss versus 0.5% of men. On placebo the figures were 1.3% of women and 0% of men [1].

Does Mounjaro cause hair loss too?

Alopecia appears on the Mounjaro label, but only in the postmarketing experience section, which means it comes from spontaneous reports after approval and the label says the frequency cannot be reliably estimated. It is not in the Mounjaro adverse reaction table with a percentage [2].

Why does Zepbound cause hair loss?

The mechanism most often proposed in published reviews is telogen effluvium, a temporary shedding that follows rapid weight loss, reduced calorie intake and lower protein and micronutrient intake. The Zepbound label itself states that hair loss adverse reactions were associated with weight reduction, which points at the weight loss rather than a direct effect on the hair follicle [1][6].

Is Zepbound hair loss permanent?

Published reviews describe telogen effluvium as typically temporary, and note that at least some reported cases have reversed. There is no long-term follow-up study of hair regrowth specifically in people who took tirzepatide, so this is described rather than proven [6].

Does tirzepatide cause more hair loss than semaglutide?

The evidence is mixed. In the only head-to-head trial, alopecia was reported by 8.3% on tirzepatide versus 6.1% on semaglutide, a small difference in a trial not designed to measure it. Some database analyses find a stronger signal for semaglutide and one 2026 analysis found tirzepatide negatively associated with hair loss reporting [3][5].

Did anyone stop Zepbound because of hair loss in the trials?

No Zepbound-treated patient discontinued because of hair loss. One placebo-treated patient did [1].

Is the FDA looking into GLP-1 hair loss?

The authors of a 2026 BMJ study state that the FDA has indicated it is evaluating hair loss as a potential safety signal for the class. As of September 14, 2026, hair loss remained on the Zepbound label as a common adverse reaction and on the Mounjaro label only as a postmarketing report [1][2][4].

This article summarizes FDA labeling, published research and company information current as of September 14, 2026. It is not medical advice and does not replace a conversation with your own healthcare provider. How we research and verify.