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Does Ozempic Cause Hair Loss? Here's What the Clinical Trials Found

Updated 2026-04-16 8 min read By Provant Labs Research Team

Yes, Ozempic and Wegovy cause hair loss. The FDA Wegovy label (semaglutide 2.4mg, the obesity dose) reports alopecia in 3% of treated adults vs 1% in placebo. Real-world estimates from endocrinologists run 25-33% of women taking GLP-1 medications. The gap between those numbers isn't a contradiction. It reflects the difference between what clinical trials formally document and what doctors see in practice.

Here's every number, from every source that has studied this question.

The FDA Label Data

The official prescribing information for Wegovy (semaglutide 2.4mg SC weekly) lists alopecia as an adverse reaction in the clinical trial section.

Adult data:

Adolescent data:

Dose-response relationship (by weight loss amount):

That last figure is the most clinically meaningful one in the FDA label. The drug doesn't cause hair loss at a fixed rate. The rate correlates with how much weight you lose. Lose more, shed more. This is consistent with the primary mechanism: telogen effluvium from rapid weight loss, not a direct semaglutide effect on follicles.

What the Ozempic label says: Ozempic (semaglutide for diabetes, up to 1-2mg weekly) doesn't list alopecia as prominently. The hair loss data comes primarily from Wegovy's obesity trials, where patients are losing significant body weight. At diabetes doses with less dramatic weight loss, the hair loss signal is weaker in formal trial data.

Phase 3 Trial Data: OASIS 1

The OASIS 1 trial (Knop et al., Lancet 2023) tested oral semaglutide 50mg daily vs placebo in a weight management population.

That 6.9% is more than double the injectable Wegovy label figure. Oral semaglutide at 50mg produced aggressive weight loss in this trial, which likely explains the higher hair loss rate.

OASIS 1 is a Phase 3 RCT. The 6.9% figure is one of the highest published alopecia rates from a semaglutide trial and represents the clearest upper-bound estimate from controlled trial data.

Phase 3 Trial Data: Tirzepatide (Mounjaro / Zepbound)

Tirzepatide (Mounjaro for diabetes, Zepbound for obesity) is a GIP/GLP-1 dual receptor agonist, different from semaglutide but in the same clinical category. Its trial data includes the most detailed sex-specific breakdown of any GLP-1 label.

SURMOUNT-1 (Jastreboff et al., NEJM 2022, Phase 3, n=2,539, 72 weeks):

Weight loss in this trial ranged from 15% (5mg) to 20.9% (15mg) vs 3.1% placebo.

SURMOUNT-3 (Wadden et al., Nature Medicine 2023, Phase 3, n=579, 72 weeks):

Pooled SURMOUNT meta-analysis (PMC11576767):

An odds ratio of 5.76 means tirzepatide-treated patients were nearly 6x more likely to report alopecia than placebo patients in these trials. That's a substantial signal.

The Zepbound FDA label sex breakdown:

No other approved GLP-1 label provides this level of sex-specific detail. The gap is stark. For women, this is not a marginal risk.

Real-World Data: Etminan et al. 2025

Clinical trials tell you what happens in a controlled population with structured follow-up. Real-world studies tell you what happens to actual patients in actual clinical practice.

Etminan et al. 2025 (medRxiv) compared 1,926 semaglutide users against 1,348 patients on bupropion-naltrexone (another weight loss medication) for hair loss outcomes.

Key results:

Hazard ratio 2.08 means women on semaglutide had more than twice the rate of hair loss events compared to women on a different weight loss medication. This isn't a comparison to untreated patients or to placebo. It's a comparison to another active treatment for obesity. The semaglutide signal is still strong.

The incidence rate of 26.5 per 1,000 person-years translates to roughly 2.65% over a 12-month period in this population, but the rate is not uniform across time. The early months of treatment, when weight loss is fastest, carry the highest risk.

Pharmacovigilance Data: FAERS Analysis

The FDA Adverse Event Reporting System (FAERS) captures spontaneous reports from patients and healthcare providers. It's not trial data, but it identifies disproportionate signals.

Godfrey et al. 2025 (JEAVD), analyzing FAERS data from 2022-2023:

An ROR above 1.0 indicates a drug-event combination reported more frequently than expected given the overall reporting database. Both semaglutide (2.46) and tirzepatide (1.73) show significant disproportionality signals. The consumer-driven reporting (84%) is consistent with a side effect that patients notice before it enters formal medical records.

Real-World Cohort Data: TriNetX 2025

The TriNetX multicenter cohort study used data from 67 healthcare organizations covering more than 100 million patients. Matched cohorts of 547,993 patients each (GLP-1 users vs non-users with similar baseline characteristics) were analyzed.

At 12 months:

This is the largest matched cohort study on this question. It finds elevated odds of three distinct hair loss diagnoses in GLP-1 users. Not one type. Three. And the androgenic alopecia signal (1.64) is notable because that's a progressive condition, not just temporary shedding.

The 3% vs 33% Discrepancy Explained

The FDA Wegovy label says 3%. Endocrinologists say 25-33%. Both are honest.

The clinical trial figure (3%) captures alopecia that participants proactively reported to investigators, that investigators found significant enough to code, and that passed through the trial's adverse event classification process. Women who noticed thinning but didn't bring it up at a visit aren't counted. Women who noticed it after the trial data cutoff aren't counted. Women who dropped out of the trial (often precisely because of side effects) are underrepresented.

The 25-33% figure comes from clinical practice: what prescribers see across thousands of patients, including callbacks between scheduled visits, patients returning to ask what to do, and observations at follow-up appointments where hair is clearly visibly thinner.

The OASIS 1 rate of 6.9%, from a trial actively measuring this outcome, and the Etminan 2025 real-world rate of approximately 2.65% per year (with higher rates in early months) together suggest the true population rate sits somewhere between the FDA label's 3% and the clinical practice estimate of 25-33%.

For a woman experiencing significant shedding on a GLP-1 medication: she's not having a rare or unexpected reaction. She may be in the majority.

Why This Doesn't Mean You Should Stop

The data makes clear that GLP-1 medications cause hair loss in a significant proportion of women. But it also makes clear that the hair loss is, for most, temporary telogen effluvium with a predictable recovery pattern. And the clinical benefit of these medications for metabolic health is substantial.

Hair loss was cited as the number one reason women stopped Mounjaro in one survey. That's a significant statistic. But stopping a medication that's controlling weight, blood sugar, and cardiovascular risk because of reversible temporary shedding is a trade-off worth examining carefully with a prescriber, not making alone.

What the data supports is this: knowing the risk, addressing the mechanisms that worsen it (protein deficiency, iron depletion, follicle environment neglect), and acting during the shedding window rather than waiting for it to stop on its own. Topical interventions with evidence behind them can make the recovery faster and less dramatic. The complete guide to GLP-1 hair loss covers the options in detail.

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FAQ

Does Ozempic cause hair loss or is it the weight loss?

Both are part of it, but rapid weight loss is the primary driver. The Wegovy FDA label shows a direct dose-response relationship: patients losing more than 20% of body weight had a 5.3% alopecia rate vs 2.5% for those losing less than 20%. The mechanism is telogen effluvium, the same shedding condition that affects women after childbirth, major surgery, or crash dieting. Semaglutide's effect on hormones (reducing LH and FSH, which lowers estrogen) is a secondary contributing factor.

What percentage of Wegovy users lose hair?

The FDA Wegovy label reports 3% vs 1% placebo. The OASIS 1 trial (oral semaglutide, Lancet 2023) found 6.9%. Etminan et al. 2025 real-world data suggests an incidence rate of 26.5 per 1,000 person-years in women. Clinical practice estimates run 25-33%. The wide range reflects the difference between formally documented trial adverse events and what patients actually experience and report.

Does Ozempic cause more hair loss than Wegovy?

Wegovy is semaglutide at 2.4mg weekly; Ozempic is semaglutide at up to 2mg weekly for diabetes. The higher obesity dose in Wegovy trials is associated with greater weight loss, which is the primary driver of hair loss. At Ozempic's lower diabetes doses in patients not losing large amounts of weight, the hair loss risk may be lower. But both contain the same molecule.

Is tirzepatide (Mounjaro/Zepbound) hair loss worse than semaglutide?

The SURMOUNT trials found 4.9-5.3% alopecia across tirzepatide dose arms vs 0.9% placebo, and the SURMOUNT-3 trial found 7.0%. The FAERS ROR for tirzepatide was 1.73 vs 2.46 for semaglutide in Godfrey 2025 analysis. The Zepbound label reports the highest sex-specific figure of any GLP-1 label: 7.1% in women. Direct head-to-head comparison doesn't exist, but the magnitude of effect appears similar between the two drugs.

Why doesn't my doctor mention hair loss as a side effect of Ozempic?

Hair loss is not listed in the Ozempic prescribing information for the diabetes indication as a primary adverse reaction, unlike the Wegovy label where it appears explicitly. Prescribers working from the Ozempic label, or who focus primarily on metabolic outcomes, may not proactively discuss it. This is a common source of frustration: "Nowhere in my extensive pre-Mounjaro research had anyone mentioned hair loss." The clinical trial documentation has caught up since 2022, but prescriber communication lags behind.

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