Wegovy® (injection) and hair loss

The hair loss rows in each document

Hair loss appears in all three US injection safety tables in section 6.1. The tables round to whole numbers; the text beneath them gives the exact figures used in the rest of this page. ^[1] The EU product information pools STEP 1–4 and the Canadian monograph STEP 1–3, and each reports a slightly different adult rate. ^[2][3]

Women reported far more of it

The US label splits the adult figures by sex. In the pool of three 2.4 mg trials (Studies 2, 3 and 4), hair loss was reported by 4% of women and 0.9% of men on Wegovy®, compared with 2% of women and no men on placebo. In the 7.2 mg trials the same pattern repeated at a higher level. ^[1]

Weight loss, the higher dose and recovery

All three documents tie hair loss to how much weight is lost. The US label says hair loss on the injection was associated with weight reduction. ^[1] The EU product information says it was reported more often in people who lost 20% or more of their weight, and the Canadian monograph gives the numbers: 5.3% in adults losing at least 20% versus 2.5% in those losing less. ^[2][3]

Hair loss rose with the higher strength: 5.8% on 7.2 mg against 3.3% on 2.4 mg and 1.0% on placebo. In the 7.2 mg group, one event led to permanently stopping treatment, one to a temporary pause and five to a dose reduction; none of these steps were taken in the other groups. ^[1] Under section 2.2, 7.2 mg is described for adults who have been on 2.4 mg for at least four weeks, so this rate applies to people who took that step with their prescriber. ^[1]

On recovery, the EU document says the events were mainly mild and most people recovered while continuing treatment. ^[2] The US label does not describe regrowth.

Teenagers and what research adds

In the 68-week adolescent trial, hair loss was reported by 4% of those on the injection and by none on placebo; the label does not split the teenage figure by sex. ^[1] The Medication Guide lists hair loss among the most common side effects for adults and for children aged 12 and older. ^[1]

A 2026 systematic review and meta-analysis pooled nine interventional studies, seven of them randomised, with 4,114 people on GLP-1 medicines. Hair loss was about three times as likely as on placebo (risk ratio 3.25), the result held when only trials in people with overweight or obesity were included, and the overall event rate on treatment was 3.9%. ^[4] The analysis grouped several medicines and could not say which type of hair loss occurred.

Why it may happen: three layers

• What the product information supports: hair loss on Wegovy® was associated with weight reduction and was more frequent with larger weight loss. ^[1][2][3]
• What it does not say: none of the documents names a type of hair loss, describes when shedding started, or shows that semaglutide acts on hair follicles directly.
• General background, not shown for Wegovy®: Cleveland Clinic describes telogen effluvium, a temporary shedding in which many hairs switch early into their resting phase after a stress or change to the body. Shedding usually appears two to three months after the trigger, and rapid weight loss or diets short of protein are among the listed triggers. ^[5] MedlinePlus similarly lists crash diets, major illness and some medicines. ^[6]

Other causes of thinning hair

Hair loss during Wegovy® treatment can have other explanations. MedlinePlus lists inherited pattern hair loss, alopecia areata (round bald patches), anaemia, thyroid disease, hormone changes, childbirth, high fever or severe infection, major surgery, emotional stress, scalp infections such as ringworm, tight hairstyles and several medicines, including retinoids, beta-blockers, some antidepressants and anti-inflammatory painkillers. ^[6] Cleveland Clinic adds that stopping birth control pills can trigger shedding. ^[5] Telling your prescriber what else changed in the months before the shedding helps them sort these out.

What general guidance describes

MedlinePlus notes that hair lost after an illness or a medicine usually grows back once the trigger has passed, and that hairpieces or a change of style can disguise thinning in the meantime. ^[6] Cleveland Clinic says most cases of telogen effluvium settle within six to eight months once the cause is addressed, and advises avoiding extreme or restrictive diets and asking a provider before adding supplements. ^[5] A provider may suggest a scalp treatment in some cases; that is a decision for them. ^[6]

The Wegovy® label offers no hair-specific measures and records dose changes only as trial events, not as advice. ^[1] The Medication Guide asks you to tell your provider about any side effect that bothers you, and any change to your dose is for your prescriber to decide. ^[1]

Wegovy® is a registered trademark of Novo Nordisk A/S. PepLabo is not affiliated with or endorsed by Novo Nordisk.

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