Before we dive in, if you want a starting point for your terrain, grab my free Drainage Starter Guide. It walks you through the first phase I start every client with.
Your hair is a lagging indicator.
By the time it’s coming out in the shower, the thing that caused it usually happened months ago.
That’s the part no one explains, and it’s why so many women panic, buy a new shampoo, use rosemary oil, start a biotin gummy or supplement, and wait. Then, nothing changes.
So, let’s start with what’s normal.
Most people lose around 100 hairs a day. That’s healthy turnover.
Each strand grows for years, rests, and sheds, and a new one grows in.
When something stresses the body enough, a large number of follicles get pushed into the resting phase at once. About two to four months later, they all shed together. It’s called telogen effluvium, and it usually lasts around six months.
There’s a reason your body does this. Hair is nonessential tissue. When resources run low or the body senses a threat, it protects your heart, brain, and organs first. Your hair is one of the first things it lets go of.
So, the real question isn’t “what shampoo should I use?” It’s “what is my body protecting itself from?”
Here are the reasons I see most often.
1. Something happened 3 months ago
Think back. Was there a surgery, a bad illness, or a high fever? A breakup, a move, a brutal quarter at work? Coming off birth control? A baby?
Any of these can trigger a shed two to four months later. If you can name the trigger, the shedding often resolves on its own once the stress is behind you. Supporting your terrain while it does helps it come back stronger.
2. You lost weight fast (including on a GLP-1)
This is the one I’m hearing about most right now.
Rapid weight loss is one of the classic triggers for that delayed shed, whether it comes from a crash diet or a GLP-1 like Ozempic, Wegovy, Mounjaro, or Zepbound. Your body reads a big, fast drop in fuel as a threat, and hair is one of the first things it stops investing in.
GLP-1s add a second layer. They turn your appetite way down, which is the point.
But, when you’re barely hungry, protein, iron, zinc, and B vitamins usually drop right along with calories. Hair is made almost entirely of protein, so it feels that gap quickly.
Most of the time, this shedding is temporary. It tends to settle once your weight stabilizes and your intake catches up.
If you’re on one, make protein your first priority at every meal, check your ferritin, and keep your bowels moving daily. GLP-1s slow digestion, and constipation is one of their most common side effects. And, please talk to your prescriber before changing your dose.
3. Your iron stores are low (and your labs might not show it)
This is one of the most common reasons I see, especially in women who menstruate.
A standard blood count can look completely normal while your iron stores are depleted. The marker that shows stores is ferritin, and it often isn’t run unless you ask for it.
Many women are told their ferritin is “normal” because it sits just above the bottom of the lab range. Many practitioners who focus on hair like to see it well above that.
4. Your thyroid isn’t converting
Both an underactive and an overactive thyroid can cause hair loss.
And, a standard panel usually checks TSH and sometimes T4. It rarely checks free T3, the active form your cells actually use.
About 20% of your T4 is converted into T3 in the gut. When gut health is compromised, conversion suffers. TSH looks normal, T4 looks normal, and you’re still shedding, cold, tired, and foggy.
Ask for TSH, free T4, free T3, reverse T3, and thyroid antibodies.
5. You’re eating well and absorbing very little
Hair is built from protein, and it needs iron, zinc, B12, and other nutrients to grow.
You can eat a beautiful diet and still be depleted if your digestion isn’t working.
Low stomach acid means you don’t break down protein or release minerals. A compromised gut lining means you don’t absorb what you do break down.
More supplements won’t fix that. The terrain has to be able to receive them first.
6. Your hormones aren’t clearing
Hormones that have done their job need to leave the body. Your liver packages them up, and your colon carries them out.
When the liver is overloaded and the bowel isn’t moving daily, more of those hormones circulate longer than they should.
For women who are sensitive to androgens, including many women with PMOS (formerly PCOS), that can show up as thinning at the crown or a widening part, often alongside jawline acne or irregular cycles.
7. Your stress hormones never come down
Chronic stress keeps cortisol elevated. That disrupts blood sugar, thyroid function, and sex hormones all at once, and it pushes the body further into protection mode.
This is why you can’t supplement your way out of a life that never lets your nervous system rest.
8. Your toxic burden is high
This one is less common, but worth considering once everything else is ruled out. Significant exposure to certain heavy metals is a known cause of hair loss.
I bring it up because most standard labs don’t look for it, and it rarely gets considered.
What I’d do first if I were you
Ask for the right labs. Ferritin, a full iron panel, a full thyroid panel (TSH, free T4, free T3, reverse T3, antibodies), vitamin D, and zinc. If your cycles are irregular or you have jawline acne, ask about androgens too.
Stop the biotin before you test. High-dose biotin can interfere with some lab results, including thyroid tests. Tell your doctor if you’re taking it.
Look back three months. Write down anything big that happened. It’s often the answer hiding in plain sight.
Start with the exits. Before any hair supplement, make sure your bowels are moving every day, you’re drinking enough water with minerals, and you’re eating enough protein. Your body has to feel safe and resourced before it puts energy back into growing hair.
Know when to see a specialist. Round bald patches, a painful, red, or scaly scalp, or very rapid loss deserve an in-person evaluation, not a protocol.
Hair loss is one of the most emotional symptoms my clients bring to me.
It’s visible and it’s scary, and it often comes with a lot of shame.
But, it’s also one of the clearest messages your body sends. It’s telling you that something upstream needs attention.
When we address that, hair usually comes back.
This post is for education only and isn’t medical advice. Please talk to your doctor about any new or sudden hair loss.
Has your hair been shedding lately? Let me know in the comments, or reply if you’re reading this in your inbox. I read every one.
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