Through either heat or suction, the skin is gently drawn upwards by creating a vacuum in a cup over the target area of the skin. The cup stays in place for five to fifteen minutes. It is believed by some to help treat pain, deep scar tissues in the muscles and connective tissue, muscle knots, and swelling; however, the efficacy of this has been questioned.
The cupping procedure commonly involves creating a small area of low air pressure next to the skin. However, there are varieties in the tools used, the methods of creating the low pressure, and the procedures followed during the treatment.
The cups can be various shapes including balls or bells, and may range in size from 1 to 3 inches (25 to 76 mm) across the opening. Plastic and glass are the most common materials used today, replacing the horn, pottery, bronze and bamboo cups used in earlier times. The low air pressure required may be created by heating the cup or the air inside it with an open flame or a bath in hot scented oils, then placing it against the skin. As the air inside the cup cools, it contracts and draws the skin slightly inside. More recently, vacuum can be created with a mechanical suction pump acting through a valve located at the top of the cup. Rubber cups are also available that squeeze the air out and adapt to uneven or bony surfaces.
In practice, cups are normally used only on softer tissue that can form a good seal with the edge of the cup. They may be used singly or with many to cover a larger area. They may be used by themselves or placed over an acupuncture needle. Skin may be lubricated, allowing the cup to move across the skin slowly.
Depending on the specific treatment, skin marking is common after the cups are removed. This may be a simple red ring that disappears quickly, the discolouration left by the cups is normally from bruising especially if dragging the cups while suctioned from one place to another to break down muscle fiber. Usually treatments are not painful.