Does Mounjaro Cause Hair Loss? Clinical Data, Causes & How to Keep It Under Control
Yes, Mounjaro can cause hair loss, but it's uncommon. In weight-loss trials of tirzepatide, the active ingredient in Mounjaro, 4–5% of people reported hair loss, compared with 1% on placebo, and nobody stopped treatment because of it (Zepbound prescribing information). Hair changes happen slowly, which is why a record helps. Glapp, the GLP-1 tracker, lets you log shedding right next to your Mounjaro doses, so you can see month by month whether it's settling.
Key numbers
| Number | What it means |
|---|---|
| 4–5% | of people on tirzepatide reported hair loss in weight-loss trials, vs 1% on placebo |
| 8,346 | users currently tracking Mounjaro-related hair loss in Glapp |
| 0 | people stopped tirzepatide because of hair loss in those trials |
Mounjaro hair loss: what the clinical evidence shows
Hair loss isn't among the most common side effects in Mounjaro's prescribing information, which lists stomach-related effects first (Lilly Medical). Tirzepatide has also been studied for weight loss, and the pooled weight-loss trials behind Zepbound's prescribing information, which uses the same molecule and the same doses, do report it:
| Group | Placebo | 5 mg | 10 mg | 15 mg |
|---|---|---|---|---|
| All participants | 1% | 5% | 4% | 5% |
| Group | Placebo | Tirzepatide (all doses) |
|---|---|---|
| Women | 1.3% | 7.1% |
| Men | 0% | 0.5% |
Source: Zepbound prescribing information, Table 1 and section 6.1.
Two things stand out. Hair loss didn't rise with dose, and the prescribing information links it to weight reduction rather than presenting it as a direct effect of tirzepatide. And it was mild enough that nobody stopped treatment because of it.
Why does Mounjaro cause hair loss?
Most hair loss on Mounjaro is telogen effluvium, a temporary type of shedding that follows a big shock to the body, like rapid weight loss or suddenly eating far less than usual. In SURMOUNT-1, people on tirzepatide lost 15–20.9% of their body weight over 72 weeks, exactly the kind of change that can set it off.
Here's how it works. Each hair follicle cycles between growing and resting. After a trigger, far more follicles than usual switch into the resting (telogen) phase at once, and about 2–4 months later those hairs fall out together. That's why shedding often shows up a few months into treatment rather than in the first weeks, and why it can feel sudden even though the cause came earlier. The follicles themselves aren't damaged, so the hair can grow back.
Telogen effluvium is more common in women in general, which may be part of why the trials saw 7.1% of women vs 0.5% of men. Your own logs can show whether your shedding started a few months after a period of fast loss or a dose step, which is useful to bring to your prescriber.
Protein, iron, zinc and vitamin D: the nutrition side of hair shedding
Hair is one of the first things your body cuts back on when food is short, so what you eat while on Mounjaro matters for your hair. Four things come up again and again:
- Protein. Hair is made of protein (keratin). General guidance is at least 0.8 g of protein per kg of body weight a day, and many experts suggest 1.0–1.2 g/kg during weight loss. When appetite is low, protein is often the first thing to drop.
- Iron (ferritin). Low iron stores are one of the most common reasons shedding lasts longer, especially in women. A ferritin blood test shows your stores.
- Zinc. It plays a part in hair growth, and intake falls when you eat much less.
- Vitamin D. Low levels are common in general and have been linked to hair shedding.
If shedding is heavy or lasting, ask your prescriber whether to check ferritin, zinc and vitamin D before you start supplements, since too much iron or zinc can cause problems of its own.
Track your Mounjaro hair loss with a GLP-1 tracker app
Hair changes happen slowly, so they're hard to judge from memory. That's what a GLP-1 tracker is for: log shedding next to your Mounjaro doses and weight, and you're in control. You'll see when it started, whether it lines up with a dose step or faster weight loss, and whether it's settling, with months of facts to show your prescriber.
Why Glapp? It's a top-rated GLP-1 tracker used by 100,000+ people, rated 4.8/5 on Trustpilot and the App Store, and 4.6/5 on Google Play. Glapp grew out of Reddit GLP-1 support groups and is built by developers who are GLP-1 users themselves, so most features come straight from community requests. Its features are grounded in peer-reviewed research and published clinical trial data, core tracking is free, and it works on iPhone, Android and web with your data synced across devices. Here's how to use it over your first three months.
Glapp does not provide medical advice or treat side effects. It shows your daily check-ins against your estimated medication levels so you have structured data to share with your prescriber.
Day 1: Start tracking your hair loss
Use Glapp's daily check-in to record hair shedding and rate how severe it feels.
Regular entries help you see whether shedding is getting better, getting worse or staying the same. Because hair loss changes slowly, you'll have a clear record of how it really went, without relying on memory over weeks and months.
Month 1: See how your hair loss changes over time
Open the side-effects chart in the Progress tab and choose the period you want to review. Your ratings appear on a timeline next to your doses, making it easier to see whether a heavy week was a one-off or part of a longer trend.
Telogen effluvium usually starts 2–4 months after its trigger, so note when your shedding began compared with your dose steps and fastest weight loss.
Month 2: Look for patterns in your weekly reports
Glapp's weekly progress reports bring your logged data together, with dedicated sections showing your side effects and how they change.
Did shedding start a few months after a dose step or a period of fast weight loss? Does it coincide with changes in hunger or food noise, and with days you ate much less? Reviewing several weeks of entries can help you spot patterns that are easy to miss day by day, and give you specific questions to discuss with your doctor.
Month 3: Bring a clear record to your doctor
After three months, review the bigger picture: is shedding slowing down, staying the same or getting heavier? For most people, telogen effluvium starts to settle once weight loss slows and eating steadies.
Create a doctor's report in Glapp and choose the information to include. Your doctor can review your symptom history alongside your doses and progress, giving you a more focused conversation about your treatment, including whether to check iron, zinc or vitamin D.
Start tracking your Mounjaro hair loss in Glapp
Hair loss and dose: does a higher Mounjaro dose mean more shedding?
Not in the trials. In tirzepatide's weight-loss trials, hair loss was reported by 5% at 5 mg, 4% at 10 mg and 5% at 15 mg, with no climb as the dose went up. Mounjaro starts at 2.5 mg once a week, moves to 5 mg after four weeks, and can rise in 2.5 mg steps (7.5, 10, 12.5 and 15 mg), at least four weeks apart.
Because shedding is linked to weight loss rather than dose, watch it against the phase of treatment: the first months, when weight comes off fastest, are when to pay attention.
See every step in the Mounjaro dosage chart and plan your next one with the titration planner.
What to bring to your prescriber
Bring a log that shows the timeline, not just the symptom:
| Week | Dose | Hair loss (weekly average) | Other side effects logged | Notes |
|---|---|---|---|---|
| Example Week 6 | 5 mg | Low | Nausea | First noticed shedding |
| Example Week 10 | 7.5 mg | Med | None | More hair on brush |
| Example Week 14 | 7.5 mg | Med | None | |
| Example Week 18 | 10 mg | Low | None | Seems to be slowing |
Questions you could ask. They're conversation starters, not recommendations; your prescriber decides what, if anything, to change.
- "My shedding started a few months into Mounjaro. Could it be linked to how fast I've been losing weight?"
- "Should we check my iron, zinc or vitamin D levels?"
- "Would it help to see someone about hair or nutrition while I'm on Mounjaro?"
Frequently asked questions
Does hair grow back after Mounjaro hair loss?
Yes, in most cases. Hair loss linked to weight loss is usually telogen effluvium, and it's temporary: the follicles stay healthy, shedding typically slows once your weight stabilizes and you're eating enough calories and protein again, and new growth starts within a few months. Because hair grows about 1 cm a month, it can take 6–12 months to look as full as before. If heavy shedding goes on for more than about six months, or you notice patches or a widening part, ask your prescriber to check for other causes. Your Glapp ratings show whether shedding is slowing.
Why do women get more hair loss on Mounjaro?
In tirzepatide's weight-loss trials, 7.1% of women reported hair loss vs 0.5% of men. Telogen effluvium is more common in women in general, though the trials don't explain the gap.
When does Mounjaro hair loss start?
Usually a few months in. Telogen effluvium shows up about 2–4 months after its trigger, which on Mounjaro is often the period of fastest weight loss.
How do I track hair loss on Mounjaro?
Add it to Glapp's daily check-in and rate it low, medium or high. The Progress chart and weekly reports show how it changes over weeks and months.
About the data
Ratings are self-reported. This page is for information only and is not medical advice; talk to your prescriber about any side effect.
About the author
We're GLP-1 patients and health tech professionals, building Glapp in collaboration with doctors. About us
Sources
- Eli Lilly. Mounjaro (tirzepatide) prescribing information: adverse reactions, dosage. Full prescribing information text.
- Lilly Medical. Common adverse events with Mounjaro in adults.
- Eli Lilly. Zepbound (tirzepatide) prescribing information: Table 1 and section 6.1 (hair loss).
- Jastreboff AM, et al. Tirzepatide once weekly for the treatment of obesity (SURMOUNT-1). N Engl J Med. 2022;387:205–16. Trial summary.