25 euthyroid volunteers were divided into two groups. Each participant of group A received 200 micrograms iodine in the form of diiodotyrosine per day for a period of eight weeks, i.e. 7 x 200 micrograms iodine/week. Each participant of group B received 1,500 micrograms iodide once a week for a period of eight weeks. In addition to the basal excretion of iodine with the collected urine, the excretion values in group A amounted to 67% of the applied dose in the eighth week. In group B, the excretion values amounted to 65% of the applied dose in the eighth week. Hence, no significant difference between both groups was found.