Compression socks are specialized hosiery items designed to provide extra support and increased blood circulation for their wearers. Some compression sock manufacturers may also use the term support socks to describe their product. Compression socks are not to be confused with traditional dress socks or non-compression diabetic socks, although they may look similar. The main purpose of compression socks is to provide graduated pressure on the lower leg and foot. Traditional dress and athletic socks offer some degree of compression, but not enough to be considered therapeutic.

The key to understanding compression socks lies in their graduated pressure application. Throughout an average day, the body pumps blood to all of the extremities as equally as it can. However, gravity often causes blood to pool in the lower legs and feet, causing circulatory problems such as edema, phlebitis and thrombosis. At the very least, all of this blood pooling can cause fatigue and leg cramps. Elevating the legs and feet may alleviate the pain temporarily, but it often returns after a few hours of constant standing or walking.

This is where the use of compression socks can be extremely beneficial. Compression socks use stronger elastics such as lycra, rubber or spandex to create significant pressure on the legs, ankles and feet. By compressing the surface veins, arteries and muscles, the circulating blood is forced through narrower channels. The arterial pressure is increased, causing more blood to return to the heart and less blood to pool in the feet. Compression socks are tightest at the ankles, gradually become less constrictive towards the knees. The soles of compression socks may be heavily padded for better shock absorption.

Although compression socks were originally marketed to those with compromised circulatory systems, many people now find their everyday use beneficial. Experts suggest passengers on long flights should wear compression socks to prevent circulatory problems like deep vein thrombosis, leg cramps and edema. Athletes often wear compression socks to give their leg muscles additional support while running or jumping. Those with occupations requiring long periods of standing may also benefit from the use of compression socks.