Hair Loss on Weight-Loss Injections: Ozempic, Wegovy, Mounjaro and Saxenda

By Dr. Mohammed AlQahtani — Consultant Dermatologist and hair loss specialist, Noya Clinic, Riyadh. Last medical review: October 2026.

At a glance. Weight-loss injections such as Ozempic and Wegovy (semaglutide), Mounjaro (tirzepatide) and Saxenda (liraglutide) are linked to hair shedding in a minority of users. In most cases the cause is telogen effluvium triggered by rapid weight loss and reduced food and protein intake, not permanent damage to the follicles. It usually begins two to four months in and settles within months of the weight stabilising. Do not stop the injections on your own; focus on protein and the right blood tests.

Do weight-loss injections really cause hair loss?

Yes, in a minority of people. In the large trials behind the US FDA approvals:

• Wegovy (semaglutide 2.4 mg): hair loss was reported in about 3% of users versus about 1% on placebo, and more often in women.
• Tirzepatide (Mounjaro, and Zepbound in some countries): hair loss reached about 5% at the highest dose versus about 1% on placebo.

A large 2026 study of several hundred thousand patients found the risk of a new hair loss diagnosis within the first year was about 43% higher with semaglutide and about 68% higher with tirzepatide compared with metformin, with no clear difference for liraglutide. These are relative increases: most people on these drugs do not develop noticeable hair loss.

Why does hair fall out on these injections?

The main cause is less the drug itself than what happens to the body: fast weight loss, eating far less than usual, and often less protein and iron. The body treats this as a shock and moves a large share of hairs from the growing phase into the resting phase at once; those hairs then shed a few weeks later. This is telogen effluvium, the same pattern seen after bariatric surgery, crash diets, childbirth and serious illness.

That is why shedding tracks the amount and speed of weight loss more than the specific injection: the faster and larger the loss, the higher the chance of shedding.

When does it start and when does it stop?

• Onset: usually two to four months after starting the injection or increasing the dose.
• Pattern: diffuse shedding from the whole scalp, noticed on the pillow, brush and in the shower, with overall thinning but no bald patches.
• Recovery: shedding usually eases within three to six months of the weight stabilising, and density returns gradually over six to twelve months.

When it is not just the injections

Weight loss sometimes unmasks a problem that was already there. Watch for:

• Pattern hair loss: thinning at the front, crown or parting that lasts beyond six months usually means androgenetic alopecia has become visible. It does not recover on its own and needs treatment.
• Iron, vitamin D or zinc deficiency: very common when intake drops, and it prolongs shedding.
• Thyroid disease: should be excluded with a blood test.
• Round bald patches, or itch, redness and scaling: these are not telogen effluvium and need direct examination.

How to protect your hair while on weight-loss injections

• Protein first: aim for roughly 1 to 1.2 g of protein per kilogram of your target weight each day (unless your doctor has restricted protein for kidney reasons), spread across meals even when appetite is low.
• Avoid losing weight too fast: discuss the pace of dose escalation with your prescribing doctor if weight is dropping very quickly.
• Test and correct deficiencies: ferritin, vitamin D and zinc, replacing only what is low, under medical supervision.
• Skip random supplements: biotin does not help without a proven deficiency, and "anti-hair-loss" shampoos do not stop telogen effluvium.
• Do not stop the injection on your own: the shedding is usually temporary, and any decision to stop belongs with your doctor.

How I approach it in clinic

We start with the diagnosis: trichoscopy of the scalp to separate temporary telogen effluvium from pattern hair loss, standardised photographs for follow-up, and blood tests where needed. If it is pure telogen effluvium, the plan is usually nutrition, correcting deficiencies and follow-up. If pattern hair loss is also present, we add appropriate treatment such as minoxidil so that no further density is lost.

When to see a dermatologist

If shedding lasts more than six months, if you notice clear thinning at the front or parting, or if you develop bald patches, itch or scalp pain. Consultations are available in English at Noya Clinic, Al Nakheel, north Riyadh; you can book a consultation here.

Frequently asked questions

Does Mounjaro or Ozempic cause permanent baldness?

No. Most hair loss on weight-loss injections is a temporary telogen effluvium caused by rapid weight loss, not damage to the follicles. It usually starts two to four months after starting the drug or raising the dose and settles within three to six months of the weight stabilising. Pre-existing pattern hair loss can become more visible, and that needs its own treatment.

My hair is falling out on weight-loss injections. Will it grow back?

In most cases, yes. Hair shed in telogen effluvium is replaced by new growth, and density usually returns over six to twelve months once weight is stable and any deficiency is corrected.

Should I stop the injections because of my hair?

Do not stop on your own. The shedding is usually temporary and stopping treatment can do more harm to your health. Ask your prescribing doctor about slowing the dose escalation if weight is falling very quickly, and focus on protein and correcting deficiencies.

Which causes more hair loss, Ozempic or Mounjaro?

In studies, hair loss was slightly more common with tirzepatide (Mounjaro) than with semaglutide (Ozempic, Wegovy). The main driver appears to be how much and how fast weight is lost rather than the drug itself.

Which blood tests should I do if my hair is shedding on these injections?

Usually ferritin (iron stores), vitamin D, zinc, thyroid function, a full blood count, and vitamin B12, particularly if you also take metformin.

Does biotin help hair loss on weight-loss injections?

Only if you have a proven deficiency, which is rare, and it can distort some blood tests such as thyroid function. Adequate protein and correcting iron and vitamin D matter far more.

References

• Wilding JPH, et al. Once-weekly semaglutide in adults with overweight or obesity (STEP 1). N Engl J Med. 2021.
• Jastreboff AM, et al. Tirzepatide once weekly for the treatment of obesity (SURMOUNT-1). N Engl J Med. 2022.
• Burke et al. Retrospective cohort of dermatology patients using GLP-1 receptor agonists. J Am Acad Dermatol. 2025.
• Lanehart MH, Zinn Z, Beatty CJ. Propensity-matched TriNetX cohort of GLP-1 receptor agonists and nonscarring hair loss. Arch Dermatol Res. 2026;318:164.
• Gupta et al. Analysis of alopecia reports with GLP-1 receptor agonists in the FDA Adverse Event Reporting System (2016–2025). J Cosmet Dermatol. 2026.

Written and medically reviewed by Dr. Mohammed AlQahtani, Consultant Dermatologist and Hair Specialist (Saudi Commission for Health Specialties). Last reviewed: October 2026. This page is for information only and does not replace an individual consultation; do not change your treatment without speaking to your doctor.