An OB-GYN's open letter to women losing hair on their GLP-1 medication

Why it happens, why it's reversible, and the 4-nutrient protocol I tell my patients about at month 3.

Over the past two years, I've watched the same scene play out in my exam room more times than I can count.

A woman sits down. She's lost weight she's been trying to lose for years. Her A1C is finally where we want it. She feels, in many ways, healthier than she has in a decade.

Then she pulls a small handful of hair from her brush. Or shows me the new wide part down the middle of her scalp. Or holds back tears as she tells me her granddaughter asked, "Why is your hair falling out?"

These are women who fought hard to start their GLP-1 medication. Most of them spent years on the diabetes carousel, the diet carousel, the willpower carousel. The medication, finally, worked.

And now, somewhere between month three and month five, their hair is falling out in clumps.

If you're reading this, you might be one of them.

I want you to know three things, and I'd like to tell you them in detail. The first is that what's happening to your hair is normal. The second is that it's reversible. The third — and this is the most important — is that you don't have to choose between losing the weight and keeping your hair.

What's actually happening to your hair

I'll explain it the way I explain it to my patients in the chair.

Your hair grows in a cycle. Most of your follicles are in anagen — the active growth phase. Roughly 10% are resting at any given time. That's normal. That's why a few strands in your brush every morning is fine.

What happens on a GLP-1 is something called telogen effluvium. It's a fancy way of saying: your body, while it's pulling resources to fuel rapid weight loss, deprioritizes your hair follicles. A much bigger percentage of them get pushed into the resting phase all at once.

Here are the four things actually causing it:

• Rapid weight loss is a stress signal. Your body doesn't know the difference between "she's losing weight on purpose with a medication" and "she's starving." It triggers the same conservation response. Hair follicles are first in line to get cut off.
• Nutrient depletion. Most women on a GLP-1 eat 30–50% less than they did before. Less food means less iron, less zinc, less B-complex, less of the protein-derived amino acids your follicles need. You can be eating "healthy" and still be falling short of what your hair specifically needs.
• Hormonal cascades. Rapid weight loss shifts your thyroid output, your cortisol, and (for women in perimenopause and beyond) your estrogen. All three influence the hair growth cycle.
• The "stuck" follicle. Once a follicle is pushed into resting phase, it needs the right signals to come back into growth. If those signals never arrive, the cycle either repeats — more shedding — or what grows back comes in finer and shorter.

This is why most of my patients see the heaviest shedding around month four. The follicles that got pushed into resting phase at month one are now releasing all their hair at once.

What I tell my patients to do

Here's what I want women in this situation to start, and I want them to start it as early as possible — ideally in the first two months of being on a GLP-1, before the shedding peaks.

I always recommend a single-formula approach over piecing together separate bottles. The four nutrients that handle the heaviest lifting are:

• Iron (in a bisglycinate form, not ferrous sulfate) — the single most under-replenished nutrient in women losing hair on a GLP-1. Without enough iron, your follicles literally cannot make hair.
• Zinc — supports the protein synthesis your hair shaft needs to build itself. Most women on a reduced-calorie diet are zinc-deficient by month three.
• Biotin (in a meaningful dose) — supports keratin production. Effective in the 2,500–5,000 mcg range, not the 30 mcg that's in a multivitamin.
• Methylated B12 — most over-the-counter B12 is the wrong form for women over 45 to absorb properly. Methylcobalamin matters.

The reason I recommend a single-formula approach is compliance. My patients who stack three or four separate bottles miss doses. The ones who take a single morning protocol stay consistent — and consistency is what restarts the cycle.

The protocol I most often recommend is two capsules every morning, with food, at the same time as your GLP-1 medication. Most of my patients see their shedding noticeably slow within 3–4 weeks. Visible new growth at the temples and crown shows up between week 8 and week 12.

What I tell my patients NOT to do

A few honest words on what doesn't work for this situation.

• Biotin gummies alone. Biotin is one piece of a four-piece puzzle. Taking it alone is like trying to bake bread with only flour.
• Minoxidil. Minoxidil works for genetic hair loss patterns. Telogen effluvium — what GLP-1s cause — is a different mechanism. You're better off addressing the cause than masking it.
• Skincare-aisle "hair growth" shampoos. Hair growth doesn't happen at the shaft. It happens at the follicle, which is below the scalp. Topical shampoos don't get there.
• Stopping your GLP-1. Please don't. The hair loss from rapid weight loss is reversible. The metabolic gains from your medication aren't. Stopping it to save your hair is a trade I would never advise.

Three patients, three timelines

I want to give you a sense of what this looks like in practice.

A final word

I'm not going to tell you that supplements are a miracle. They're not. They're nutrients your body needs in order to do something it's already trying to do — restart hair growth.

What I will tell you, after seeing this in dozens of patients, is that the women who start the protocol early do markedly better than the women who wait until the wide part shows in photos. If you're at month two and you haven't seen heavy shedding yet, this is the time. If you're at month six and the shedding is heavy, it's still the time — your follicles aren't gone, they're paused.

The protocol I recommend is the one linked below.