Deficiency of micronutrients may represent a modifiable risk factor associated with the development, prevention, and treatment of decreased hair and nail quality or hair loss. The aim of this monocentric, single-arm intervention study was therefore to investigate whether taking a food supplement with a rational composition of components affects hair and nail quality in women. A validated and non-invasive tool, the Trichoscale method, was used to quantify hair loss / hair growth.Subjective evaluation of hair and nail quality was also carried out by subjects and experts using a questionnaire. Intake of the dietary supplement resulted in significant improvement in hair status in several key parameters.The number of hairs in the growth phase significantly increased when compared to baseline (+7.5% after 8 weeks, +10.7% after 16 weeks), as did the density of adult fully pigmented hairs per square centimetre (+2.6% after 8 weeks; +5.9% after 16 weeks). Hair and nail quality improved significantly according to both the self-evaluation of the female participants and the assessment by a dermatological expert. The results of the Trichoscale method and subjective evaluations consistently demonstrated the beneficial effects of a food supplement on hair growth and nail quality in women.