Iron and Hair Loss: What No One’s Telling You
Is your hair getting thinner, drier, or just not the same after 40?
Your thyroid is fine.
Your hormones look okay (ish).
And yet… you’re still shedding like crazy.
Have you checked your iron? Like, really checked it the right way?
Hair loss and low iron go hand in hand — and most women have no idea why.
Let’s fix that.
When “Normal” Labs Aren’t Normal
Here’s what’s wild: you can have “normal” labs — even a normal CBC (complete blood count) — and still be losing hair.
Why? Because your body might not have enough iron where it matters most: inside your hair follicles.
Iron isn’t just about energy. It’s literally what fuels new hair growth.
Without it, your follicles shift into “survival mode,” slowing growth and triggering more shedding.
Symptoms of Low Iron (Besides Hair Loss)
If you’re low in iron, you might also notice:
Fatigue or low energy
Shortness of breath
Rapid heart rate
Weakness
Pale skin (or pale lower eyelids when you pull them down)
Brittle nails
Restless legs
Easy bruising
How Low Iron Is Diagnosed
Your provider may start with a CBC, which looks at:
Red blood cells (RBC)
Hemoglobin (Hgb)
Hematocrit (Hct)
But here’s the catch — you can have a normal CBC and still have low iron stores.
That’s why ferritin (your iron storage protein) is critical to test.
Most labs list “normal” ferritin as 15–150 ng/mL, but that range is outdated.
The American Gastroenterological Association recently updated the lower limit to 45 ng/mL — a huge difference.
For years, I’ve argued that women feel awful (and shed hair like crazy) with ferritin below 50 ng/mL.
Many are told they’re “fine” at 17, 20, or 30 — but their hair, energy, and mood say otherwise.
Other helpful labs:
Serum Iron
TIBC (Total Iron Binding Capacity)
% Saturation
Why Iron Gets Low
Low iron isn’t always about diet. There are lots of reasons your levels could dip — and you can have more than one.
🥩 You’re not eating enough iron.
Vegan or vegetarian
Not a red meat fan
💥 You’re not absorbing it.
H. pylori infection
Medications that block absorption (antacids, PPIs)
Celiac disease or SIBO
Ulcerative colitis or Crohn’s disease
General gut inflammation or “leaky gut”
🩸 You’re losing it.
Heavy periods (hello, perimenopause!)
Ulcers, hemorrhoids, or GI bleeding
🩺 Chronic inflammation or disease.
Conditions that trap iron in storage — low serum iron but normal or high ferritin.
How to Treat It
Do you just take iron?
Maybe — but not before finding out why your iron is low in the first place.
Because if your gut’s not absorbing or you’re losing iron every month, supplements are just a band-aid.
Work with your provider to:
Identify the cause (diet, gut, or bleeding).
Choose the right form of iron (some are much easier on digestion).
Re-test every 3–4 months.
Other Causes of Hair Loss
Iron isn’t the only reason your hair might be thinning. Other contributors include:
High androgens (testosterone or DHT)
PCOS
Low or fluctuating estrogens (especially in perimenopause)
High cortisol or stress — shedding often appears 2–3 months after a stressful event
Hair care products or water changes (hard vs. soft water, new shampoo, well water, etc.)
Low minerals (zinc, selenium, magnesium)
Medications (especially SSRIs like Prozac or Zoloft, birth control pills, steroids, and excess testosterone therapy)
Chemotherapy
Bottom Line
If your hair is falling out and your labs look “normal,” don’t stop there.
Ask for your ferritin — and make sure it’s above 45ng/mL for healthy hair growth.
Your body can’t grow lush, strong hair when it’s stuck in low-iron survival mode.
So before you buy another supplement or shampoo, check your labs first.
Your follicles will thank you later. 💁♀️