You’ve read that low iron makes your hair fall out, and now the iron pills in the vitamin aisle look like an easy fix. Low iron can cause hair loss, and hair can regrow once your body has enough again. Dermatologists agree on that much. What’s less clear is how often iron is the real reason a woman is shedding. The studies point in different directions. So iron is worth checking, especially if you have heavy periods. But it’s a question for a blood test, not a guess. Too much iron is harmful, and your body has no good way to get rid of the extra.
What ferritin is, and why it comes up
Ferritin is a protein that stores iron in your body. A ferritin blood test shows roughly how much iron you have in reserve, which is why it comes up when people talk about shedding. You need iron to make healthy red blood cells. When the reserve runs low for long enough, you can end up with iron-deficiency anemia, the most common type of anemia.
NHLBI, the National Institutes of Health’s heart, lung and blood institute, says mild or moderate iron-deficiency anemia may cause no symptoms at all. More serious cases bring tiredness, shortness of breath, dizziness, cold hands and feet, and pale skin.
The common reasons women run low are the ones you’d guess, plus a few you might not:
- Heavy periods, or bleeding during childbirth
- Pregnancy
- Endurance sports, which can drain iron in a couple of ways
- Celiac disease, Crohn’s, ulcerative colitis or H. pylori infection, which can stop you from absorbing iron
- Weight-loss surgery or other surgery on the stomach and intestines
- Regular aspirin or pain relievers like ibuprofen and naproxen, which can cause bleeding in the gut
What the research says about ferritin and shedding
The American Academy of Dermatology lists too little iron among the causes of noticeable hair loss, along with too little protein, zinc or biotin. It says hair can regrow once the body gets enough of what’s missing. The studies disagree on how strong the link is.
| Study | Who was in it | What it found |
| University of Pennsylvania, Journal of Investigative Dermatology, 2003 | 106 women with hair loss, 11 without | Average ferritin was lower in women with pattern hair loss and alopecia areata than in the comparison group; not significantly lower in telogen effluvium |
| Duke University, Journal of the American Academy of Dermatology, 2010 | 381 women with pattern hair loss or chronic shedding, 76 without | Iron deficiency was common in all groups, and no more common in women with hair loss than in those without |
| Cleveland Clinic review, Journal of the American Academy of Dermatology, 2006 | A review of the earlier studies | Some studies link low iron to hair loss and others don’t; not enough evidence to screen everyone with hair loss or to give iron when there’s deficiency without anemia |
The Duke numbers are the surprise. Using a ferritin cutoff of 15, about 12% of premenopausal women with hair loss were low in iron. Among women with no hair loss, it was nearly 30%. At a cutoff of 40, it was roughly 59% and 64%, against 72%. Low iron was simply common in women, thinning hair or not.
Both studies have limits. The 2003 comparison group was only 11 women. The 2010 study included only white women from one clinic, and its authors said no one knows yet whether fixing low iron helps hair loss. Neither can prove cause and effect.
The 2006 review’s authors added a practical note. Their clinic checks iron in hair-loss patients anyway, though they admit the habit isn’t backed by solid evidence. Treating iron-deficiency anemia is standard, they wrote. Treating low iron without anemia is debated.
Why you test before you take anything
Too much iron is harmful. MedlinePlus, from the National Library of Medicine, says taking more iron than you need can cause serious medical problems. The National Institute of Diabetes and Digestive and Kidney Diseases notes the body has no good way to get rid of iron. In hemochromatosis, a genetic condition where the body absorbs too much, the buildup can lead to liver damage (cirrhosis), diabetes or heart failure.
Iron pills are dangerous to children. An iron overdose is especially dangerous for kids. A severe one can happen when a child gets into adult vitamins, prenatal vitamins included. If you keep iron at home, keep it out of reach.
The cause matters as much as the number. Low iron is a finding, not a diagnosis. The 2006 review stresses that the reason you’re low has to be found. For some people, that means checking for blood loss in the gut.
Our post on iron deficiency signs and foods covers the food side.
What testing looks like
It’s a standard blood draw. To check for iron-deficiency anemia, a doctor will usually order a complete blood count, hemoglobin, blood iron and ferritin. You may be asked to fast for 12 hours before a ferritin test, so ask when you book.
Reading the result isn’t always simple. Inflammation can push ferritin up, for example after an infection or surgery. So can liver disease, obesity, autoimmune disease or an overactive thyroid. Some medicines move it too. So your number belongs with the doctor who ordered it, not next to a target someone posted online.
If your iron turns out to be low
The plan and any dose are your doctor’s call, but here’s what to expect.
Iron pills are the most common treatment for iron-deficiency anemia. NHLBI says it often takes three to six months to bring iron levels back up. MedlinePlus says blood counts usually recover in about two months. After that, you keep taking supplements for another six to twelve months to refill your stores. Iron through an IV is an option for more serious or long-term cases.
Side effects include a metallic taste, upset stomach, constipation or diarrhea, and black stools. If they bother you, tell your doctor instead of quietly stopping.
Iron also gets in the way of other things. It can make some antibiotics, like tetracycline and ciprofloxacin, work less well, along with Parkinson’s and seizure medicines. Milk, calcium and antacids cut how much iron you absorb, so doses are usually spaced at least two hours apart. Medicines that lower stomach acid can also get in the way. Bring your full medication list to the appointment.
Hair runs on a slower clock than blood. Even after your iron is back up, regrowth takes months to show. If your iron is fixed and your hair still isn’t recovering, something else may be going on, like hereditary thinning.
Food still counts
Good sources include lean red meat, salmon, eggs, beans, peas, tofu, dried fruit, dark leafy greens and iron-fortified breads and cereals. Foods high in vitamin C, like oranges, strawberries and tomatoes, help you absorb iron. Black tea can cut absorption, so keep it away from your iron-heavy meals.
One more supplement note. Biotin gets lumped in with iron in “hair vitamin” ads, but it’s a different story with its own evidence problem. Our post on biotin for hair growth covers it.
Hair care while you sort it out
None of these change your iron level. They keep the hair you have in better shape and help it look fuller while you wait for answers.
Prices move constantly, so we link to live listings instead of printing a number that is wrong by the time you read it. Links go to Amazon, which is where a referral gets credited.
Biolage Volume Boost Shampoo is about $27 for 13.5 ounces, though the price changes often. It’s made for fine hair, with soy protein for lift at the roots, and it’s paraben-free and safe for color-treated hair. It does contain sulfates and fragrance. If your scalp is sensitive, a plainer shampoo is the better choice.
Wet Brush Original Detangler is about $8. Its bendy bristles are made to move through knots on wet or dry hair. Wet Brush says they cause less breakage than a leading competitor’s.
Living Proof Full Thickening Blow-Dry Cream is about $34 for 3.7 ounces. It’s a light, silicone-free cream that protects against heat up to 450°F. Smooth it through clean, damp, detangled hair from the middle to the ends, comb it through, and blow-dry with a round brush. Living Proof says it gives 30% thicker-looking hair.
How we picked
There are no supplements here on purpose. Whether you need iron is for a blood test and a doctor to decide. The picks are a volume shampoo, a gentle detangler and one styling cream, each chosen for fine or thinning hair.
Your next step
If you have heavy periods and your hair is thinning, ask your doctor for a complete blood count and ferritin. It’s a cheap, simple test.
If you’re tempted to start iron “just in case,” don’t. Test first. Extra iron has real risks and does nothing for your hair if you weren’t low.
If your ferritin comes back low, ask why it’s low, not just how to raise it. Ask how long it should take to come back up, too.
If your iron is normal and you’re still shedding, look elsewhere. Your thyroid, a trigger two or three months back, or hereditary thinning could be behind it. Our guide to hair thinning in women lays out the other causes.
If you’ve had weight-loss surgery or have celiac or Crohn’s, mention it. Trouble absorbing iron changes the whole picture.
FAQ
Can low iron cause hair loss without anemia?
Possibly, but the evidence is mixed. Dermatologists disagree on whether to treat low iron without anemia for hair. That’s why the decision belongs with your doctor.
What ferritin level do I need for my hair?
There’s no agreed number for hair. Your doctor will read your result against your lab’s range and your other tests.
How long after fixing low iron will my hair grow back?
Bringing iron levels back up often takes three to six months, and regrowth shows after that. Expect a long wait.
Bottom line
Low iron is a real, fixable cause of hair loss. But it’s one cause among several, and the studies haven’t agreed on how big a role it plays. Get tested if you have symptoms or risk factors, and treat what the test finds with your doctor’s help. Skip the iron-just-in-case. More is in our hair archive.
