GLP-1 and Hair Loss: Why It Happens, How Long, and What Helps

You're 3 months into semaglutide or tirzepatide.
The weight is coming off. Your energy is better. Your labs are improving.

Then you look at your shower drain.

Or your hairbrush.
Or the back of your shirt.

And your stomach drops.

First: you're not imagining it.
Second: you're not alone. This comes up in every GLP-1 patient community.
Third: it's almost certainly temporary.

Here's what's actually going on, how long it lasts, and what you can do about it right now.

It's Not the Medication. It's the Weight Loss.

This is the most important thing to understand.

Semaglutide (Ozempic/Wegovy) and tirzepatide (Mounjaro/Zepbound) don't directly cause hair loss.
Rapid weight loss does.

The medical name is telogen effluvium.
It's your body's stress response to a major caloric shift.

Here's how it works in plain English:

Your hair has 3 phases: growing (anagen), resting (telogen), and shedding (exogen).
At any given time, about 85–90% of your hair is growing and 10–15% is resting.

When your body goes through a major stress — rapid weight loss, surgery, pregnancy, severe illness — it shifts more hair follicles from growing to resting.
Instead of 10% resting, suddenly 25–30% is resting.

2–3 months later, all those resting hairs fall out at once.
That's why the shedding starts around months 3–4 on GLP-1 — it's a delayed reaction to the caloric deficit that started when you began medication.

Key point: This happens with ANY rapid weight loss method. Bariatric surgery patients experience it at even higher rates (50–70%). It's not unique to GLP-1. You can read more about telogen effluvium and weight loss and the AAD's overview of hair loss types.

The Hair Loss Timeline: When It Starts, Peaks, and Stops

Source: Dermatology literature on telogen effluvium + GLP-1 clinical trial adverse event data (STEP and SURMOUNT trials).

The peak is months 4–6. That's when patients panic.
But look at the rest of the timeline: it stops, and it grows back.
Almost always.

Who's More Likely to Lose Hair on GLP-1?

Not everyone experiences this. Several factors increase risk:

Faster weight loss. Patients losing more than 1–2 lbs per week consistently are at higher risk. The faster the deficit, the bigger the shock to your follicles.

Low protein intake. This is the biggest controllable factor. Patients eating under 60g protein daily have significantly more hair thinning. Hair is made of protein (keratin). No building blocks = no hair growth.

Iron deficiency. Common in women, especially with reduced food intake on GLP-1. Low ferritin (below 30 ng/mL) is strongly linked to hair loss even without medication.

Rapid dose increases. Moving up doses faster than every 4 weeks means your caloric intake drops more abruptly. Slower titration = gentler on hair.

History of hair thinning. If you've experienced postpartum hair loss, stress-related shedding, or telogen effluvium before, you're more susceptible.

Nutrient gaps. Zinc, biotin, vitamin D, and omega-3 deficiencies all contribute. On GLP-1, you're eating less food total — which means less of everything. Research confirms the link between iron deficiency and hair loss.

7 Things That Actually Help (Ranked by Evidence)

1. Protein: 80–100g Daily (The #1 Factor)

This is the single most effective intervention.
Hair is built from keratin, which is protein.
If your body doesn't have enough protein, hair is the first thing it sacrifices.
Your body will always prioritize organs over hair.

Target: 80–100g protein daily. Non-negotiable during months 1–8.
How: 2 meals with 25–35g protein each + 1 protein shake (30g) = 80–95g.
This alone prevents the worst of it for most patients.

2. Iron: Get Your Ferritin Checked

Ask your doctor to check ferritin (not just hemoglobin) at your next lab draw.
Optimal for hair: ferritin above 50 ng/mL. Many dermatologists prefer above 70.
If yours is low, an iron supplement (ferrous bisglycinate is gentle on the stomach) can make a measurable difference within 8–12 weeks.
Don't supplement iron without testing first — too much iron is harmful.

3. Collagen Peptides: 10–20g Daily

Collagen provides the amino acids (glycine, proline) that support hair structure.
Brands like Vital Proteins, Sports Research, or Great Lakes dissolve in coffee or a shake.
Evidence is moderate but the downside is near zero.
Easy add: 1 scoop in your morning coffee or protein shake. Tasteless.

4. Biotin: 2,500–5,000 mcg Daily

Biotin (vitamin B7) supports keratin production.
Most GLP-1 patients are getting less from food due to reduced intake.
A standalone biotin supplement or a hair-specific multivitamin (like Nutrafol) covers this.

5. Zinc: 15–30mg Daily

Zinc deficiency is linked to hair loss independently of weight loss.
On GLP-1, you're eating less of everything — including zinc-rich foods like red meat and shellfish.
A basic zinc supplement (zinc picolinate is well-absorbed) fills the gap.

6. Slow Down Weight Loss (If Possible)

Losing 1–1.5 lbs per week is gentler on hair follicles than 2–3 lbs per week.
If your hair loss is severe and distressing, talk to your provider about:
Extending time between dose increases.
Staying at a lower dose longer.
Slightly increasing caloric intake (especially protein).

This doesn't mean stopping medication. It means calibrating the speed of loss.

7. Minoxidil (Rogaine): Ask Your Dermatologist

Topical minoxidil 5% (Rogaine or generic) is FDA-approved for hair regrowth.
It won't fix telogen effluvium directly — but it can stimulate new growth while waiting for natural recovery.
Available over-the-counter. Foam version is easiest to use.
Takes 3–6 months to see results. Must be used consistently.

Some dermatologists also prescribe low-dose oral minoxidil (1.25–2.5mg) for more diffuse thinning. This requires a prescription and monitoring. Learn more about minoxidil for hair loss from the AAD.

The Hair Protection Cheat Sheet (Save This)

Tip: Screenshot this table and keep it in your phone.

What Doesn't Work (Save Your Money)

The hair loss supplement industry is massive and mostly unregulated. Some things to skip:

Sugar bear gummies and Instagram hair vitamins: Mostly sugar and marketing. A $10 biotin supplement does the same thing a $40 gummy does.

Expensive shampoos claiming to stop hair loss: Shampoo sits on your scalp for 60 seconds. It can't fix a nutritional or hormonal issue. Ketoconazole shampoo (Nizoral) has some evidence for hair health but won't reverse telogen effluvium.

Stopping GLP-1 medication: Stopping the medication won't immediately regrow hair. The shedding cycle takes 3–6 months to resolve regardless. And you lose all the metabolic benefits. In most cases, staying on medication while optimizing nutrition is the better choice.

The Mistake: Panicking and Quitting Medication

Hair loss is emotionally devastating. Especially for women.
The instinct is to stop whatever's "causing" it.

But stopping GLP-1 won't stop the shedding that's already in motion.
Hair that shifted to telogen 2–3 months ago will fall out regardless.
Stopping medication means you lose the metabolic, cardiac, and weight benefits — without actually saving your hair.

The better approach: Talk to your provider AND a dermatologist. Optimize protein, check labs, consider slowing dose increases. Treat the cause (nutrition + rate of loss) instead of removing the treatment.

When to See a Dermatologist (Not Just Your GLP-1 Provider)

Your GLP-1 provider manages your medication. A dermatologist manages your hair.
See one if:

Hair loss is patchy (clumps missing) rather than diffuse (overall thinning).
Shedding hasn't slowed by month 8.
You see scalp redness, itching, or scaling.
Hair loss started before GLP-1 medication.
You have a family history of pattern baldness.

Patchy loss could indicate alopecia areata or another condition unrelated to weight loss.
A dermatologist can do a scalp biopsy or trichoscopy to rule out other causes. Use the AAD dermatologist finder to locate one near you.

Try This Tonight

Add up your protein from today. Be honest.
If it's under 60g, that's likely contributing more than any supplement deficiency.

Tomorrow, add one protein shake (30g) and one high-protein meal (30g).
That gets you to 60g minimum as a starting floor.

Then: at your next doctor's appointment, ask for a ferritin level.
Write it in your phone notes so you remember.

Those two actions — more protein and a ferritin check — are worth more than any $80 hair supplement on Amazon.

FAQ