Hair loss is on both labels, and the number is almost entirely a women's number
This is the rare side effect where the label is more informative than the literature. Hair loss appears in the common adverse reactions list on both approved GLP-1 weight products, with rates from the trials attached, and the rates rise with dose. Break them down by sex, as both labels do, and the picture changes completely: 8.4% of women against 0.2% of men at the highest semaglutide dose. No randomized trial with hair loss in its title or abstract is indexed in PubMed at all.
What this comes down to
- On the semaglutide label, hair loss was reported in 3.3% of patients at 2.4 mg against 1% on placebo, and in 5.8% at 7.2 mg. The label attributes it to the weight reduction rather than to the drug directly.
- The sex split is the finding. At 7.2 mg the label reports 8.4% of female patients and 0.2% of male patients; at 2.4 mg, 5.4% of female patients and none of the male patients in that pool.
- The tirzepatide label reports hair loss in 4% to 5% of treated patients against 1% on placebo, and the same sex split: 7.1% of female patients against 0.5% of male patients.
- Zero randomized trials carry a hair loss or alopecia term. The identical filter returns 44 trials for nausea with the same drugs, so the filter is not the problem.
The numbers that are already published
Hair loss sits in the semaglutide label's list of adverse reactions reported in at least 5% of adults and pediatric patients aged 12 and older, alongside nausea, diarrhea and the rest. The adverse reaction table gives 1% on placebo, 3% at 2.4 mg and 6% at 7.2 mg. A dedicated paragraph in the clinical trials section is more precise: in a pool of three studies, hair loss was reported in 3.3% of patients treated at 2.4 mg and 1% on placebo, and in the 7.2 mg trials, 5.8% at 7.2 mg, 3.3% at 2.4 mg and 1.0% on placebo[1]. A pediatric trial reported 4% against none on placebo.
| Label and group | Rate | Female | Male |
|---|---|---|---|
| Semaglutide 7.2 mg | 5.8% | 8.4% | 0.2% |
| Semaglutide 2.4 mg, same pool | 3.3% | 5.4% | None reported |
| Semaglutide placebo, same pool | 1.0% | 1.5% | Not separately given |
| Tirzepatide, pooled studies | 4% to 5% | 7.1% | 0.5% |
| Tirzepatide placebo | 1% | 1.3% | None reported |
Hair loss, as reported on the two approved labels
The tirzepatide label lists hair loss among adverse reactions reported in at least 5% of treated patients, gives 1% on placebo against 5%, 4% and 5% across the three doses in its table, and carries the same sex breakdown: 7.1% of female patients against 0.5% of male patients on the drug, and 1.3% against none on placebo[2]. It adds a detail worth keeping: no treated patient discontinued because of it, and one placebo patient did.
Each label introduces its hair loss paragraph by saying the adverse reactions were associated with weight reduction. That is the manufacturer's reading of its own data, and it is consistent with what the rate does across doses — more weight lost, more reports. It is not a claim anybody has tested against a control that lost the same weight another way.
And the literature that does not exist
PubMed, via the E-utilities API
(semaglutide[tiab] OR tirzepatide[tiab]) AND (alopecia[tiab] OR "hair loss"[tiab]) AND "randomized controlled trial"[pt] AND "humans"[mh]
Returned 0. Positive control — the same drugs and nausea, identical filter — returned 44 through the identical filter in the same session.
The control is deliberately another side effect of the same drugs through the same filter, because the question is whether the trial literature indexes adverse-effect work at all. It does — 44 records for nausea. Dropping the trial filter, hair loss and alopecia with these drugs returns 33 records in total: reviews, scoping reviews, a retrospective cohort and correspondence. The rates exist; they exist inside labels rather than inside papers.
What has been published is observational and small. A retrospective cohort in the dermatology literature looked at hair loss among people taking these drugs[3]. A 2025 systematic review found five studies covering 2,905 adults and described the findings as conflicting — some reporting improvement and regrowth, others reporting hair loss as an adverse dermatological event — and closed by calling for research to clarify the relationship[4]. A review of five studies that disagree with each other is a description of an open question, not an answer to it — and thirty-three records is the whole published field[5].
How to use this when you are buying
- If you are a woman starting one of these drugs, the label rate that applies to you is roughly the one in the female column, not the headline. Both labels publish that split and no marketing page we have read repeats it.
- The rate rises with dose on the semaglutide label, which makes it one more thing that changes as you climb the ladder — and the ladder has a price attached too.
- A compounded product's label will not carry any of this, because a compounded preparation has no FDA-approved labeling. What compounded and brand actually mean is the article about that gap.
- Nobody here holds a license to tell you what to do about hair shedding. What we can say is that it appears on both labels, with rates, and that a prescriber who says it is not a known effect has not read them. Side effects by how often trials reported them covers the rest of the table.
Questions people actually ask
Does semaglutide cause hair loss?
Hair loss is a listed adverse reaction on the approved semaglutide weight label. In a pool of three studies it was reported in 3.3% of patients at 2.4 mg against 1% on placebo, and in the higher-dose trials in 5.8% of patients at 7.2 mg.
Is it worse for women?
The label rates say so. At 7.2 mg semaglutide, hair loss was reported in 8.4% of female patients and 0.2% of male patients. The tirzepatide label reports 7.1% of female patients against 0.5% of male patients.
Is it the drug or the weight loss?
Both labels say the hair loss adverse reactions were associated with weight reduction, which is the manufacturers' reading of their own trial data. Nobody has tested it against a control group losing the same weight by another route.
Why are there no trials about it?
There are, in the sense that the label numbers come from randomized trials. What there is none of is a published trial with hair loss as its subject: PubMed indexes zero with an alopecia or hair loss term, while the same filter returns 44 for nausea with the same drugs.
Sources
Every source here was fetched and read for this article, with the identifier taken off the record that came back and the claim it supports written down beside it. All of it was read in September 2026, the same session the rest of this page draws on.
- 1.WEGOVY (semaglutide) injection and tablets — FDA prescribing information. DailyMed, National Library of Medicine, Structured Product Labeling, 2026. Source · Document dated June 2026Hair loss appears in the SPL's list of adverse reactions reported in at least 5% of adult and pediatric patients aged 12 and older. Its adverse reaction table gives 1% placebo, 3% at 2.4 mg once weekly and 6% at 7.2 mg once weekly. The clinical trials section states that hair loss adverse reactions were associated with weight reduction and reports, in a pool of studies 2, 3 and 4, hair loss in 3.3% of patients treated with 2.4 mg (4% female, 0.9% male) and 1% on placebo (2% female, 0 male); in a pediatric trial, 4% on 2.4 mg and none on placebo; and in the 7.2 mg trials, 5.8% at 7.2 mg (8.4% female, 0.2% male), 3.3% at 2.4 mg (5.4% female, 0 male) and 1.0% on placebo (1.5% female).
- 2.ZEPBOUND (tirzepatide) injection — FDA prescribing information. DailyMed, National Library of Medicine, Structured Product Labeling, 2026. Source · Document dated August 2026Hair loss appears among adverse reactions reported in at least 5% of treated patients, with the adverse reaction table giving 1% placebo against 5%, 4% and 5% at 5 mg, 10 mg and 15 mg. The clinical trials section states that hair loss adverse reactions were associated with weight reduction and that in a pool of Study 1 and Study 2 hair loss was reported more frequently in female than male patients, 7.1% female versus 0.5% male on the drug and 1.3% female versus 0% male on placebo, with no treated patient and one placebo patient discontinuing because of it.
- 3.Glucagon-like peptide-1 receptor agonist medications and hair loss: A retrospective cohort study. Journal of the American Academy of Dermatology, 2025. PMID 39863171 · doi:10.1016/j.jaad.2025.01.046A retrospective cohort study of hair loss among users of GLP-1 receptor agonist medications, published as a research letter in the dermatology literature; the PubMed record carries no abstract, so it is cited here for the existence and design of the study rather than for a result.
- 4.Hair Loss Associated With Glucagon-Like Peptide-1 (GLP-1) Receptor Agonist Use: A Systematic Review. Cureus, 2025. PMID 41111833 · doi:10.7759/cureus.92454A systematic review including five relevant studies encompassing 2,905 adult patients, which reports conflicting findings — some indicating significant improvement and hair regrowth, others reporting hair loss as an adverse dermatological event — and recommends further research to clarify the relationship between these drugs and alopecia.
- 5.PubMed, queried through the E-utilities API. National Library of Medicine, 2026. SourceOn 2026-09-12, semaglutide or tirzepatide with an alopecia or hair loss term through the randomized-trial and human-indexing filter returned 0; the same drug and hair terms without the trial filter returned 33; the same drugs with nausea through the identical trial filter returned 44 and semaglutide alone returned 316.
Key figures