* L-Cystine (sulphur-containing amino acid) is one of the essential components of hair (18%), nails (14%) and, to a Lesser extent, skin (2% to 4%). L-Cystine is contained in the keratin of hair and nails. It speeds up the proliferation of keratin-rich cells and this has a positive effect on the growth of hair and nails. High cystine levels appear, especially in the hair, 4 to 6 weeks after the tablets have been taken. * Vitamin B6 is a vital factor in the use of L-Cystine. It allows for the integration of L-Cystine in keratin-forming areas. The nutritional balance between L-Cystine and vitamin B6 is necessary because a B6 deficiency leads to a drop in the incorporation of L-Cystine into hair and nails. * Arginine is an amino acid found in high concentrations in active hair follicles. It acts in synergy with L-Cystine, complementing its effect. * Zinc is also required for the formation of keratin. Moreover, it inhibits an enzyme that is responsible for hair loss. Its action is given much greater potential by the presence of vitamin B6.