Iron Deficiency and Hair Loss: The Connection
Last reviewed: March 21, 2026, 7:02 a.m.
The relationship between iron deficiency and hair loss has been debated among dermatologists and researchers for decades, but a growing body of evidence supports a meaningful connection. Iron is essential for numerous biological processes, including DNA synthesis in rapidly dividing cells like those in hair follicles, oxygen transport via hemoglobin, and the activity of ribonucleotide reductase, a rate-limiting enzyme for cell division. Hair matrix cells in the anagen follicle bulb are among the most rapidly dividing cells in the body, making them particularly vulnerable to iron depletion.
Several large observational studies have found that serum ferritin levels below 30 ng/mL are associated with increased hair shedding, particularly in premenopausal women. A landmark 2006 study by Rushton published in Clinical and Experimental Dermatology proposed that ferritin levels of at least 70 ng/mL may be optimal for hair health, significantly higher than the lower reference range used to diagnose anemia. This threshold remains widely cited in trichology literature, though it is important to note that ferritin is also an acute-phase reactant that can be elevated by inflammation, potentially masking underlying iron depletion.
Women are disproportionately affected by iron deficiency-related hair loss due to menstrual blood loss, with an estimated 12% of premenopausal women having depleted iron stores. Other high-risk groups include vegetarians and vegans, endurance athletes, frequent blood donors, individuals with celiac disease or inflammatory bowel disease, and those who have undergone bariatric surgery. Pregnancy also significantly increases iron demands, contributing to the multifactorial nature of postpartum hair loss.
When supplementing iron, the form matters significantly for both absorption and tolerability. Ferrous bisglycinate is generally better tolerated and absorbed than ferrous sulfate, causing fewer gastrointestinal side effects. Taking iron with vitamin C may enhance absorption, while calcium, coffee, tea, and high-fiber foods can inhibit it. Typical supplemental doses range from 18 to 65 mg of elemental iron daily, but dosing should be guided by laboratory values, as excessive iron intake can cause oxidative damage and is particularly dangerous for individuals with hemochromatosis.
If you suspect iron deficiency is contributing to your hair loss, a comprehensive blood panel including serum ferritin, serum iron, total iron-binding capacity (TIBC), and a complete blood count is recommended. Simply checking hemoglobin alone can miss iron depletion without anemia, which may still be sufficient to affect hair follicle function. Work with your healthcare provider to establish your baseline levels, set a target ferritin level, and monitor progress with periodic blood work.
Several large observational studies have found that serum ferritin levels below 30 ng/mL are associated with increased hair shedding, particularly in premenopausal women. A landmark 2006 study by Rushton published in Clinical and Experimental Dermatology proposed that ferritin levels of at least 70 ng/mL may be optimal for hair health, significantly higher than the lower reference range used to diagnose anemia. This threshold remains widely cited in trichology literature, though it is important to note that ferritin is also an acute-phase reactant that can be elevated by inflammation, potentially masking underlying iron depletion.
Women are disproportionately affected by iron deficiency-related hair loss due to menstrual blood loss, with an estimated 12% of premenopausal women having depleted iron stores. Other high-risk groups include vegetarians and vegans, endurance athletes, frequent blood donors, individuals with celiac disease or inflammatory bowel disease, and those who have undergone bariatric surgery. Pregnancy also significantly increases iron demands, contributing to the multifactorial nature of postpartum hair loss.
When supplementing iron, the form matters significantly for both absorption and tolerability. Ferrous bisglycinate is generally better tolerated and absorbed than ferrous sulfate, causing fewer gastrointestinal side effects. Taking iron with vitamin C may enhance absorption, while calcium, coffee, tea, and high-fiber foods can inhibit it. Typical supplemental doses range from 18 to 65 mg of elemental iron daily, but dosing should be guided by laboratory values, as excessive iron intake can cause oxidative damage and is particularly dangerous for individuals with hemochromatosis.
If you suspect iron deficiency is contributing to your hair loss, a comprehensive blood panel including serum ferritin, serum iron, total iron-binding capacity (TIBC), and a complete blood count is recommended. Simply checking hemoglobin alone can miss iron depletion without anemia, which may still be sufficient to affect hair follicle function. Work with your healthcare provider to establish your baseline levels, set a target ferritin level, and monitor progress with periodic blood work.