Iron deficiency is one of the most common — and most frequently missed — causes of hair loss, particularly in women. The connection between iron levels and hair health is well-established, and correcting a deficiency often produces significant improvement in hair shedding.
How Iron Deficiency Causes Hair Loss
Hair follicles are among the most metabolically active cells in the body and require a constant supply of nutrients — including iron — to function normally. Iron is essential for the production of haemoglobin (which carries oxygen in red blood cells) and plays a direct role in DNA synthesis and cell division in the hair matrix (the actively dividing cells at the base of the follicle).
When iron stores are depleted, the body prioritises iron delivery to vital organs over hair follicles. This causes follicles to enter the resting (telogen) phase prematurely, resulting in increased shedding (telogen effluvium).
Ferritin: The Key Measurement
Regular blood tests measure serum iron and haemoglobin — but for hair loss, the most relevant measurement is serum ferritin (the body's iron storage protein). A patient can have a normal haemoglobin level but low ferritin stores, and still experience significant hair shedding.
The normal laboratory reference range for ferritin is typically 12–150 ng/mL, but many hair loss specialists recommend ferritin levels of at least 50–70 ng/mL for optimal hair growth. Patients with ferritin below this level, even within the "normal" range, may experience shedding that resolves when ferritin is raised.
Who Is Most at Risk?
- Women with heavy menstrual periods
- Pregnant women
- Vegans and vegetarians (non-haem iron from plant sources is less bioavailable)
- Patients with coeliac disease or inflammatory bowel disease affecting iron absorption
- Blood donors and athletes
Symptoms Beyond Hair Loss
Low iron/ferritin may cause fatigue, poor concentration, cold hands and feet, and restless legs — in addition to hair shedding. Many patients present with hair loss as their primary complaint without recognising the associated symptoms.
Treatment
Iron supplementation corrects the deficiency, but hair recovery takes time. Expect 3–6 months of supplementation before ferritin levels significantly improve, and a further 2–4 months before hair shedding visibly reduces.
Dietary approaches (increasing red meat, beans, leafy greens, and taking vitamin C with iron-rich meals to aid absorption) can supplement oral iron tablets.
Is Hair Transplant Appropriate for Iron-Related Hair Loss?
No. Hair loss caused by iron deficiency is diffuse and reversible. Transplantation into a scalp with ongoing nutritional deficiency will produce poor graft survival. The deficiency must be fully corrected before any consideration of transplantation.
If patterned hair loss persists after ferritin has been adequately corrected for 12 months, other causes — including co-existing androgenetic alopecia — should be assessed.
Experiencing diffuse hair shedding? Our team will advise on assessment including nutritional testing before determining whether transplantation is appropriate.