Does Semaglutide Cause Hair Loss in Women (and Does It Grow Back)?

If you started a GLP-1 medication and noticed more hair in your brush, you are not imagining it, and you are not alone. Here is what the research actually says, and why the picture can look a little different for women.

The short answer

Hair loss is a recognized but uncommon side effect of semaglutide, and in most cases it is not the drug directly damaging your follicles. The far more likely driver is fast weight loss and the nutritional stress that comes with it. In the STEP trials that supported Wegovy's approval, hair loss was reported by roughly 3 percent of adults on semaglutide compared with about 1 percent on placebo, and the rate rose to about 5.3 percent in people who lost more than 20 percent of their body weight. The good news buried in those numbers: the large majority of users did not report meaningful shedding, and when it does happen it is usually temporary.

What the data shows, especially for women

Women appear in these reports more often than men. In the STEP trial data, hair loss was recorded in about 4 percent of women versus roughly 0.9 percent of men on semaglutide 2.4 mg. A separate analysis reported by CNBC found that people on semaglutide had a 52 percent higher risk of hair loss than people taking a different weight loss drug, Contrave, and that women taking semaglutide had more than twice the risk of hair loss compared with women in the Contrave group. The authors were careful to note their data was driven mostly by women, with 22 cases of hair loss in women and just one in a man, so they could not cleanly compare the sexes. Newer analyses point the same way. A 2026 systematic review summarized this year found that tirzepatide, which tends to produce the greatest weight loss, was linked to the largest signal, and UK regulators logged hundreds of hair loss reports tied to these drugs.

Why the mechanism matters

The pattern almost everyone describes is telogen effluvium, a temporary shift of hair follicles from the growing phase into the resting phase after a physical stressor. Rapid weight loss, a sharp drop in calories, and low intake of protein, iron, zinc, and other nutrients can all nudge the hair cycle in that direction. Because appetite drops on a GLP-1, some women simply are not eating enough of the building blocks hair needs, and nausea or vomiting can add to nutrient losses. This is why the effect scales with how fast and how much weight comes off, rather than with the medication being inherently toxic to hair.

The women-specific overlap

Hair changes rarely happen in a vacuum. Semaglutide shedding can land at the same time as other hormonal shifts, so it is worth zooming out. Women with PCOS, now increasingly called PMOS, often have elevated androgens that can independently drive thinning, a subject we cover in our piece on GLP-1s and fertility in PCOS. Perimenopause and menopause bring their own hormone changes that affect hair, and how your body responds to a GLP-1 can shift too, something we explore in our article on menopause hormone therapy and GLP-1s. Iron deficiency, which is more common in menstruating women, is another well-known contributor to shedding. Untangling which factor is at play is exactly the kind of thing a clinician can help with.

What people find useful to watch

None of this is a reason to stop a medication on your own, and none of it is medical advice. But because the shedding tracks with pace of weight loss and nutrient gaps, general information from clinicians and trial data tends to focus on the same themes: steady rather than crash weight loss, enough protein, and attention to iron and other minerals. Patterns that do not fit telogen effluvium, such as patchy bald spots, scaly plaques, or scalp pain, are usually a sign to get evaluated for a different cause.

Because hair changes can move with your weight loss curve and your cycle at the same time, keeping a simple log helps you and your clinician spot what is really going on. You can track doses, weight, appetite, and symptoms like shedding in one place with PepFem, and note how they line up with your period. If your cycle itself has shifted since starting treatment, our article on period changes on GLP-1s is a helpful companion read.