Iron deficiency, or low levels of iron in the blood, is one of the most common nutritional deficiencies in the world. Having suboptimal iron levels affects the body’s ability to produce red blood cells, which in turn impacts its efficiency at carrying oxygen around the body. This affects a wide range of bodily functions, leading to symptoms like fatigue, weakness, dizziness, fainting and more.
But can low iron also affect your hair?
Research suggests it can lead to certain types of alopecia and hair shedding. However, it’s not the leading cause of hair loss (especially in men), so we’re going to cover the signs to look out for if you’re unsure what’s causing your hair loss.
The link between iron deficiency and hair loss
Low iron is most common in premenopausal women, usually cause by menstrual blood loss or pregnancy. In men and postmenopausal women, iron deficiency is typically driven by malabsorption, gastrointestinal blood loss or poor diet.
A systematic review compared 36 studies, involving a total of 10,029 women, to investigate the link between iron deficiency and hair loss. It found that women with alopecia had lower levels of iron than controls, and around 21% had ferritin levels indicative of iron deficiency. The review concluded that lower iron stores are associated with hair loss.
Another meta-analysis investigated the association between telogen effluvium and iron deficiency. Telogen effluvium is a type of alopecia caused by a sudden systemic shock, like extreme weight loss, illness, surgery or another significant event, that causes temporary hair shedding. One trigger can be nutritional deficiency. Again, by considering 20 studies, researchers found patients with telogen effluvium had lower ferritin and iron levels than healthy controls, leading them to conclude that iron deficiency could play a role in hair shedding.
The evidence isn’t always clear-cut though. Some studies find that low iron isn’t enough to explain hair shedding, as not all people with low iron experience hair loss. Plus, the threshold for defining iron deficiency can be inconsistent. Generally, the threshold is defined as ferritin levels less than 30 ng/mL for both men and women.
Is there a link between male pattern baldness and iron?
As you’ve probably noticed, most research focuses on women as iron deficiency is considerably more common in women. On the other hand, the leading cause of hair loss in men is androgenetic alopecia (male pattern baldness), which is genetic. Evidence linking male pattern baldness to iron deficiency is limited. Although iron deficiency can contribute to hair thinning, it’s unlikely to be linked to male pattern baldness.
Male pattern baldness is driven by a genetic sensitivity to a hormone called DHT, which binds to and gradually shrinks hair follicles on the scalp, causing thinning and eventually baldness if left untreated – it is not directly related to nutrition.
How to find out if low iron is causing your hair loss
If you're experiencing increased shedding, particularly thinning all over the scalp, it's worth speaking to your GP about a blood test. Measuring ferritin and other iron markers can help determine whether iron deficiency may be contributing to your symptoms.
It's important not to start taking iron supplements without confirming a deficiency first. Excessive iron intake can lead to its own health complications and, in some cases, may also contribute to hair shedding.
Different kinds of hair loss typically have telltale signs which can help you identify the underlying cause.
Telogen effluvium usually leads to sudden hair shedding all over the scalp and typically follows about 3 to 6 months after a stressful event.
Male pattern baldness gets its name from the characteristic pattern of hair loss it causes. Thinning typically begins at the temples, hairline or crown before gradually progressing over time, while the hair on the back and sides of the scalp remains largely unaffected. If your hair loss has developed slowly and is concentrated around these areas, male pattern baldness is the most likely cause.
Haemochromatosis
Although most research focuses on the link between low iron levels and hair loss, ironically, the link between too much iron and hair loss receives less attention despite evidence there could be an association there. Haemochromatosis is a genetic condition which causes the body to store too much iron, which if left untreated, can lead to serious damage to the liver, heart and pancreas. Ireland has the highest rates of haemochromatosis in the world, with 1 in 5 people carrying the gene and 1 in 83 at risk of developing it.
A 2024 systematic review found that alopecia was reported in 75.7% of patients with haemochromatosis across 5 studies. The alopecia manifested in various forms, from partial hair loss to alopecia totalis in 12% of patients, which is total hair loss across the entire body.
Takeaway
Hair loss can be driven by any number of underlying conditions. If hair loss gradually worsens over several years along the hairline and crown, it’s probably male pattern baldness, which does not indicate any serious underlying health concerns. It can be treated with licensed treatments like Minoxidil Spray and Finasteride tablets.
If hair loss is sudden, diffuse (meaning all-over the scalp) or rapid, it could indicate there is a more systemic issue at play than male pattern hair loss alone. In that case, we recommend speaking to your doctor to investigate potential causes and solutions.
All of our blog articles are reviewed by our Medical Director before publication.
