The supplement effect of Cu, Fe, K, Mg, Mn and Zn chelated with glycine on the absorption of these elements by animals was evaluated. The evaluation was carried out by comparing the mineral concentrations found in hair of the animals before and after 47 days of supplementation with a combination of glycine-mineral chelates. Five horses known to be clinically well were used for this study. Instrumental neutron activation analysis (INAA) was applied to the determination of Cu, Fe, K, Mg, Mn and Zn concentrations in the horse hair samples. It was observed that the supplementation helps the Fe, K and Zn absorption by the animal organism. The data obtained suggest that the hair is a suitable material to investigate Fe, K and Zn in mineral metabolism in the animal organism.