Can low ferritin cause hair loss?

Low ferritin levels, reflecting depleted iron stores, are frequently associated with hair loss in women, particularly telogen effluvium (excessive shedding) and female pattern hair loss. While clinical "normal" ranges for ferritin often begin as low as 12–15 ng/mL, research suggests these levels are often insufficient for optimal hair follicle function.

Clinical and observational evidence

Clinical data consistently demonstrates a correlation between low serum ferritin and hair thinning.

• Case-Control Findings: Meta-analyses of women with non-scarring alopecia show significantly lower mean ferritin levels compared to controls, with differences often ranging from 18 to 20 ng/mL.
• Thresholds for Growth: While 30 ng/mL is often a clinical cutoff for iron deficiency, studies indicate that hair regrowth may require levels as high as 60–70 ng/mL. In one study, 86% of patients with chronic telogen effluvium had ferritin levels below 40 ng/mL.
• Prevalence: Lower ferritin concentrations are found more frequently in patients with hair loss than in the general population, suggesting that even "low-normal" iron stores can trigger shedding.

Mechanistic explanations

The biological link between iron and hair growth centers on the high metabolic demands of the hair follicle.

• Cellular Proliferation: Hair follicle matrix cells are among the most rapidly dividing in the body. This rapid turnover requires constant DNA synthesis.
• Enzymatic Cofactor: Iron is a critical cofactor for ribonucleotide reductase (RNR), the rate-limiting enzyme for DNA synthesis. When iron stores (ferritin) are low, RNR activity may be impaired, stalling cell division in the hair bulb.
• Cycle Disruption: Depleted iron stores likely signal the follicle to prematurely exit the anagen (growth) phase and enter the telogen (resting) phase, leading to increased shedding several months later.

Bottom line

Low ferritin is a plausible and clinically recognized factor in female hair loss. Maintaining ferritin levels well above the standard clinical minimum—often targeted at ≥60 ng/mL—is frequently necessary to support normal hair follicle cycling and regrowth.