As the appearance of hair and nails is a major concern for woman worldwide, we have tried to collect the most reliable therapeutic sources with a particular interest for micronutrients. The latter is a term used to include trace elements found in minerals, vitamins, amino acids, and herbs. Some of them may be used in both hair and nails, for example, biotin or cystine. There is a general tendency to reverse the conclusion from some deficiency states of certain substances leading to poor hair and nail growth and/or quality that their administration would improve hair and nails even without a proven lack. But, generally speaking, there is a lack of scientific evidence that the nutrients have a real effect on hair and nail quality. Consequently, despite some anecdotal reports relating that some substances are able to improve hair and/or nails changes, in clinical practice, the results obtained are still disappointing when we are confronted to problems.