Do Wegovy, Ozempic, and Mounjaro Cause Hair Loss?

Hair loss can occur, but the evidence does not yet show that these drugs directly damage hair follicles. Hair shedding has been reported after semaglutide—the active ingredient in Wegovy and Ozempic—and tirzepatide, the active ingredient in Mounjaro. Weight-management trials also recorded hair loss more often with active treatment than with placebo. The leading explanation, however, is telogen effluvium triggered by rapid weight loss, reduced food intake, or the stress of a major physical change, rather than proven direct toxicity to the follicle. A direct drug effect remains possible but unconfirmed.^{aad-glp1systematic-review}

Wegovy, Ozempic, and Mounjaro are not interchangeable names

Some brands share an active ingredient, which can make the evidence confusing.

Brand	Active ingredient	Main uses in U.S. prescribing information
Wegovy	Semaglutide	Long-term weight management in eligible people with obesity or overweight, among other indications
Ozempic	Semaglutide	Glycemic control in adults with type 2 diabetes and reduction of certain cardiovascular and kidney risks
Mounjaro	Tirzepatide	Glycemic control in adults with type 2 diabetes
Zepbound	Tirzepatide	Long-term weight management in eligible people with obesity or overweight, among other indications

Wegovy and Ozempic therefore contain the same active ingredient, as do Mounjaro and Zepbound, but their approved uses, doses, and trial populations are not identical. Approvals also vary by country. The brand names should not be treated as interchangeable, and patients should not switch products on their own.^{wegovy-labelozempic-labelmounjaro-labelzepbound-label}

How often was hair loss reported in trials?

In the FDA's 2026 Wegovy prescribing information, pooled adult weight-reduction trials reported hair loss in 3.3% of participants receiving semaglutide 2.4 mg and 1% receiving placebo. The corresponding rates were 4% versus 2% among women and 0.9% versus 0% among men. The label states that these adverse reactions were associated with weight reduction.^wegovy-label

The U.S. label for Zepbound, the weight-management brand of tirzepatide, also states that hair-loss adverse reactions were associated with weight reduction. In pooled data from two trials, hair loss was reported in 7.1% of women receiving Zepbound versus 1.3% receiving placebo. Among men, the rates were 0.5% and 0%, respectively.^{zepbound-label}

These percentages should not be applied to every Wegovy or Mounjaro user. The trials differed in dose, population, follow-up, and adverse-event reporting, and the term “hair loss” does not establish a specific diagnosis or cause. Hair loss is also not listed among the most common adverse reactions in the U.S. diabetes labels for Ozempic or Mounjaro.^{ozempic-labelmounjaro-label}

A systematic review of evidence available through 2025 found signals for hair loss after semaglutide and tirzepatide, but much of the evidence came from retrospective studies and adverse-event reporting databases. Hair-loss subtype, timing, and sex differences were often poorly documented, so the review could not establish a direct causal relationship.^{systematic-review}

Why might shedding happen?

1. Rapid weight loss can trigger telogen effluvium

A major physical change can shift more hairs than usual from the growth phase into the resting phase. The result may be diffuse shedding that becomes noticeable a few months after weight loss begins rather than immediately. Dermatologists call this telogen effluvium. The American Academy of Dermatology lists substantial weight loss as a common trigger and notes that, once the body readjusts, excessive shedding often stops and fullness tends to return within six to nine months.^aad-shedding

The course is not identical for everyone. Shedding may last longer when weight loss or restricted intake continues, or when another cause of hair loss is present.

2. Reduced intake may contribute

GLP-1–based treatments can substantially reduce appetite and food intake. If total calories or protein fall too low, or if a true nutrient deficiency develops, the change can place additional stress on the hair cycle. The American Academy of Dermatology identifies sudden weight loss and reduced intake of protein, vitamins, or other nutrients as possible explanations for shedding reported with these drugs.^aad-glp1

That does not mean everyone with shedding should take high-dose iron, zinc, or biotin. Nutritional needs and deficiencies differ, and excessive supplementation can cause harm. If food intake has fallen sharply, review it with the prescribing clinician or a qualified dietitian. Testing should be guided by symptoms, diet, and medical history rather than ordered as the same panel for everyone.

3. A direct drug effect remains uncertain

Researchers have also proposed that GLP-1–based drugs could affect the hair cycle directly, but mechanistic and prospective clinical evidence remains limited. Current research cannot determine whether an individual's shedding comes from the drug, the weight change, or a combination of factors.^{aad-glp1systematic-review}

Should you stop the medication?

Do not stop Wegovy or Mounjaro, or change the dose, solely because of shedding without speaking to the prescriber. The decision should account for the treatment's benefits, the pace of weight change, other adverse effects, and available alternatives. Useful details to bring to the appointment include:

• medication start and dose-escalation dates, along with weight changes
• when shedding began and whether it is diffuse or localized
• current food and protein intake and any recent vomiting or diarrhea
• recent childbirth, surgery, fever, infection, or major stress
• other medications and supplements recently started or stopped
• a family or personal history of pattern hair loss

Monthly photographs of the part and hairline in consistent lighting and from the same angle can help document change. Counting every hair in the shower is highly variable and may increase anxiety without clarifying the diagnosis.

When to see a dermatologist

Telogen effluvium usually causes increased shedding across the scalp. Do not assume weight loss is the explanation if you notice:

• sudden round or patchy areas of loss
• scalp pain, marked itching, redness, scale, or pustules
• smooth, shiny, or scar-like areas where follicle openings are absent
• progressive thinning limited mainly to the hairline or crown
• rapidly worsening shedding or shedding that does not ease over several months
• fatigue, cold intolerance, menstrual changes, or other systemic symptoms

Telogen effluvium can also make underlying male- or female-pattern hair loss become noticeable sooner. Alopecia areata and inflammatory or scarring scalp diseases require different management. Identifying the type of loss first helps avoid unnecessary supplements and inappropriate treatment.

Bottom line

Hair loss can occur after starting Wegovy, Ozempic, Mounjaro, or related medication. Reports were more frequent with active treatment than placebo in weight-management trials of Wegovy and tirzepatide. The available evidence points to rapid weight loss and reduced intake as important triggers of telogen effluvium, but it does not prove that these drugs directly damage follicles. Instead of stopping treatment on your own, discuss the pace of weight loss and nutrition with the prescriber, and see a dermatologist if the pattern is unusual or continues to worsen.

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