Weakened nails and significant hair loss are phenomena that may have a common underlying cause. Excluding specific pathologies, such as onychomycosis or alopecia, the conditions that lead to the fragility of nails and hair are often the same. They range from environmental factors - change of season or intense cold - to genetic reasons. From incorrect habits - an unbalanced diet or periods of particular stress - to hormonal changes. We can also mention heavy pharmacological treatments, the use of aggressive products - be they dyes or nail polishes - or pathologies like anemia or thyroid imbalances. In all cases, the supplementation of vitamins and minerals, fundamental players in many metabolic processes, has proved to be a useful support for strengthening damaged nails and hair.