Iron deficiency and hair loss in women: the link and what to test

I often get asked whether hair loss is caused by an iron deficiency. The honest answer is: sometimes iron plays a part, but far from always. The evidence for a direct link between ferritin and hair loss is mixed, and many studies contradict each other.

Still, testing your iron status is a sensible step when your hair thins. A deficiency is easy to detect and, if present, straightforward to address. In this article you will read what the link really is, which blood values you can test and which other causes you should not overlook.

Important upfront: this article explains, it does not diagnose. Always discuss ongoing hair loss with your GP.

Can iron deficiency cause hair loss?

Iron deficiency can contribute to hair loss in some women, but it is rarely the only cause. Hair roots need iron to divide, so a marked deficiency can disturb hair growth. Yet not all studies find a clear link, so see it as a possible factor, not the certain culprit.

The form most often linked to iron is telogen effluvium. In it many hairs enter the resting phase at once and fall out a few months later. That can follow a marked iron deficiency, but also fever, surgery, stress or childbirth.

Women have a higher risk of iron deficiency than men, mainly through menstruation, pregnancy and a plant-based diet. That often makes testing your iron status worthwhile with hair loss, even though the link is not present in everyone.

How is ferritin related to your hair?

Ferritin is the protein that stores your iron reserve, and it is the value mentioned most often with hair loss. The idea is that your hair roots are among the first to run short of iron when your reserve depletes. The evidence for a precise threshold, however, is weak.

Some researchers argue ferritin should be above 30 or even 70 micrograms per litre with hair loss. Other studies find no difference in ferritin between women with and without hair loss. That contradiction is exactly why your result always belongs in context.

What is certain: a truly low ferritin points to an empty iron reserve, and that is worth addressing regardless of your hair. Whether topping up iron actually makes your hair thicker varies per person and is not guaranteed.

Which blood values do you test for hair loss?

With hair loss you do not look at iron alone. A sensible set includes your ferritin and your iron, plus your thyroid value (TSH), because a slow or fast thyroid also causes hair loss. That way you know you are turning the right dial.

The table below shows the main values and what they tell you. Note: this is explanation, not a reference frame to diagnose yourself with.

Want to go deeper into the iron values? Then read our explainer on the ferritin level and what a low ferritin means. And if you suspect more than iron is at play, look at which hormones you can test with hair loss.

What other causes of hair loss are there?

Hair loss often has several causes at once, and iron is only one of them. Hereditary hair loss, hormonal changes around menopause, a thyroid condition, stress and certain medicines all occur. So an iron deficiency is never automatically the explanation.

According to Thuisarts.nl and the NHG, telogen effluvium after a major event is one of the most common forms in women. Think of childbirth, fever, a crash diet or a period of high stress. This type often recovers on its own within six to twelve months.

Hereditary hair loss, in women too, is gradual instead and is not explained by iron. If you see a clear pattern, such as a widening part, blood testing alone is not enough. Your GP can look at the pattern and the timeline with you.

What can you do?

The first step is finding out whether there really is a deficiency, rather than guessing. Have your ferritin, iron and TSH tested, and discuss a low ferritin or an abnormal thyroid with your GP. Do not start taking high doses of iron on your own.

Too much iron is not harmless and can cause complaints and even damage. You only top up iron with a proven deficiency and preferably under guidance. The Voedingscentrum also notes that you already get plenty of iron through food, such as wholegrains, legumes and green vegetables.

Give your hair time as well. Even if you top up iron, it often takes three to six months before you notice anything in your hair, because hair grows slowly. If the loss keeps going or you see bald patches, go back to your GP.

Testing your own values

If you want to know quickly how your iron reserve stands, you can have your blood drawn at Lunara without a referral. The Iron Status test looks at values like ferritin and iron, so you can rule out or map a deficiency.

You order online, get drawn at one of over 750 locations in the morning, and your results are reviewed by a BIG-registered doctor. That way you get not just numbers, but interpretation too.

If you think you might have anaemia, also read our overview on anaemia in women and which blood values to test. Testing yourself is a handy starting point, but it does not replace the conversation with your GP.

Frequently asked questions

At which ferritin value do you get hair loss?

There is no hard cut-off for this. Some doctors use 30 micrograms per litre as a lower limit with hair loss, but the evidence for that is weak and not everyone agrees. So always discuss your result in context with your GP.

Will my hair grow back if I address my iron deficiency?

Sometimes, but it is not a guarantee. If an iron deficiency really was the cause, your hair can recover after a few months. If something else is at play too, such as your thyroid or a hereditary predisposition, iron alone is not enough.

Do I have to be fasting for an iron test?

For ferritin you usually do not need to be fasting. Serum iron swings a lot through the day and after a meal, so a morning draw gives a more reliable picture. The draw location will tell you whether fasting is needed.

When should I see the GP about hair loss?

Go in with ongoing or sudden loss, bald patches, or if your hair loss comes with other complaints such as fatigue. Your GP looks at the pattern and can request targeted blood testing.

References

1. Thuisarts.nl. I have hair loss. Dutch College of General Practitioners (NHG).
2. NHG. Treatment guideline hair loss (alopecia). Dutch College of General Practitioners.
3. Voedingscentrum. Iron: which foods contain it and how much you need.

Every blood test result through Lunara includes a professional assessment by a BIG-registered doctor. Blood testing through Lunara does not replace a visit to your GP. Always discuss ongoing hair loss or an abnormal result with your GP.