Once the CEP compression socks are on your feet, you realize you are not just wearing socks. These are a performance enhancing sock, and yes, they are legal. Originally designed for medicinal purposes, medi Gmbh has transferred their expertise into the sports and recreation world with a full line of socks for everything from trekking to badminton. Compression socks and clothing are shown to improve circulation and oxygen in the blood, which reduces fatigue and lactic acid build up.