Why Is My Hair Falling Out? How Iron Deficiency Causes Hair Loss in Women

You notice more hair on your pillow each morning. The shower drain clogs faster than usual. When you run your fingers through your hair, strands slip out without any tugging. Your ponytail feels thinner, and your part looks wider than it used to.

Low iron is one of the recognised triggers of this kind of all-over shedding, alongside illness, surgery, childbirth and crash dieting. It's worth checking because it's common in women, especially with heavy periods or after pregnancy. And unlike genetic thinning, it can be treated.

Exactly how low iron affects hair follicles isn't fully understood. The shedding is spread across the scalp, and once the deficiency is corrected, hair takes months to recover.

How Iron Deficiency Actually Causes Hair Loss

Iron is part of haemoglobin, the protein in red blood cells that carries oxygen around your body. Your body also keeps a store of iron, measured in a blood test as ferritin. That store can run down well before you become anaemic.

That's why a normal blood count doesn't rule iron out. Ferritin can also look falsely normal when there's inflammation in the body. In the StatPearls review, a low ferritin confirms iron deficiency, but a normal one doesn't fully exclude it.

Unlike genetic thinning, which widens the part, low iron causes volume loss all over. Telling normal shedding from actual loss is a useful first step.

Signs Your Hair Loss Is Iron-Related

Iron deficiency rarely shows up in your hair alone. The NHS lists tiredness, shortness of breath, heart palpitations, pale skin and headaches as the common symptoms. Less common ones include hair loss, craving non-food items like ice or paper, restless legs and changes to your nails.

Mention heavy periods to your doctor too. They're easy to dismiss as normal.

The hair loss itself affects the whole scalp rather than making patches, and it often builds over months. If you're also seeing thinning at your hairline, look at tight styles as well, because low iron doesn't usually single out one area.

Getting the Right Tests Done

A full blood count shows whether you're anaemic, but it doesn't measure your iron stores. Ask for ferritin as well. When doctors investigate heavy shedding, they typically check a full blood count, serum iron, iron saturation and ferritin, plus a thyroid test if you have symptoms of an underactive thyroid.

If your ferritin sits near the bottom of the normal range and you're shedding heavily, ask your doctor what they make of it rather than taking normal as the final word.

Ask about the cause, too. Heavy periods, pregnancy, coeliac disease and other gut conditions can all lower iron, and the NHS adds bleeding from the gut, which can come from stomach ulcers or regular use of painkillers like ibuprofen and aspirin. Stress is a separate trigger for shedding and can sit on top of low iron.

Treating Low Iron Safely

Only take iron if a blood test shows you need it, and let your doctor set the dose. According to the NIH Office of Dietary Supplements, the upper limit for adults is 45 mg a day from all sources unless a doctor prescribes more. Very high doses can cause organ failure, and accidental iron overdose is a leading cause of fatal poisoning in children under 6, so keep tablets out of reach.

If you are low, iron tablets are the usual treatment, and the NHS says they're usually taken for about six months. Constipation, nausea and stomach pain are common side effects, and taking tablets with or soon after food may help. Orange juice may improve absorption, while tea, coffee, milk and calcium supplements close to your dose can reduce it. Iron can also interfere with some medicines, including levothyroxine, so ask your pharmacist about timing.

Food helps keep your levels up once they're back to normal. Heme iron from meat, poultry and seafood is absorbed more easily than the non-heme iron in plants and fortified foods. Eating lentils, beans or leafy greens with vitamin C-rich foods like citrus or tomatoes helps you absorb more.

Looking after your scalp won't fix low iron, but gentle handling means less breakage while your hair grows back.

Frequently Asked Questions

How long does it take for hair to grow back after treating iron deficiency?

Expect months, not weeks. The shedding has to settle first, and after telogen shedding, regrowth can take up to six months to start and longer before you notice it. Keep taking treatment for as long as your doctor advises, even before your hair looks different.

Can you have iron deficiency hair loss with normal blood work?

It's possible. A standard full blood count checks for anaemia, not your iron stores, so ask for ferritin too. Ferritin can also read normal when there's inflammation in the body, so a doctor may look at iron saturation as well.

Will iron supplements make my hair grow back thicker?

Only if low iron was part of the problem. Correcting a deficiency can let shed hair regrow, but extra iron won't make hair thicker than your natural baseline, and taking it without a proven deficiency can be harmful. Get a blood test first.