Ferritin is a protein that stores iron in the body and releases it in a controlled fashion. It serves as a key indicator of the body’s iron reserves. Scientific evidence supports a connection between ferritin levels and nail health, particularly in the context of iron deficiency. Low ferritin is associated with brittle nails and a specific nail abnormality called koilonychia (spoon-shaped nails). Multiple studies have shown that individuals with unexplained brittle nails or nail dystrophy frequently have reduced serum ferritin, and iron supplementation that raises ferritin levels can improve these nail problems.

The rationale is that iron is essential for cell proliferation and differentiation, including in the nail matrix where nail growth occurs. Insufficient iron impairs these processes, leading to weaker, malformed nails. However, it is important to note that ferritin itself is not a supplement, but rather a marker measured in blood tests to evaluate iron stores. Iron supplementation may be recommended when ferritin is low, particularly when nail changes are present alongside other symptoms of deficiency. In healthy individuals with normal ferritin, additional iron is not beneficial and could be harmful.

Thus, scientific evidence supports the use of ferritin measurement and, if low, iron supplementation to support nail health in cases of iron deficiency. There is no evidence for benefit if ferritin is already in the normal range.