This randomized, double-blind, placebo-controlled study was designed to investigate the efficacy and tolerability of Nourkrin, a new natural agent for the treatment of hair loss based on marine proteins, and minerals and vitamins. Fifty-five subjects with hair loss of different aetiologies participated in the 6-month blinded phase of the study. Objective assessments showed a significant positive effect of treatment on hair growth. Intake of the active preparation for a further 6 months in an open phase indicated a subjective further improvement in hair growth. Exposure of the patients previously treated with placebo to the active preparation for 12 months gave similar results. Tolerability was good and no side-effects were reported. Nourkrin may provide an alternative to pharmacotherapy for the treatment of hair-loss problems in individuals with androgenetic alopecia.