Evidence check: Eisen-Ferritin Selbsttest in the context of Haut

An iron-ferritin self-test measures ferritin levels in the blood, which reflect the body's iron stores. In the context of skin health, ferritin is often linked to hair loss, brittle nails, or pale skin. However, the evidence for a direct causal relationship between low ferritin and specific skin issues is mostly mechanistic and observational. Studies suggest that iron deficiency can impair oxygen delivery to the skin and disrupt collagen synthesis, but effects vary widely among individuals. A self-test can provide a rough indication but does not replace clinical diagnosis. Many factors—inflammation, infection, or chronic disease—affect ferritin levels independently of iron status. Additionally, elevated ferritin may indicate iron overload, which can also cause skin problems (e.g., hyperpigmentation). Without medical interpretation, there is a risk of misinterpretation and unnecessary supplementation. The overall evidence level is mechanistic to mixed: the biomarker is well-established, but the direct benefit of a self-test for skin health is not supported by randomized controlled trials.