You may have heard about athletes like Tiger Woods getting platelet-rich plasma (PRP) injections to help heal an injury. These shots, which are based on your own blood, are increasingly being used to treat sports injuries and to help wounds heal after surgery. Some doctors even use it as a cosmetic procedure to target signs of aging, such as wrinkles. But does it work? Here’s what to keep in mind.

WHAT IS IN A PRP SHOT?

Plasma is the liquid part of your blood that’s mostly made of water and protein. It lets red and white blood cells and platelets move through your bloodstream. Platelets are a type of blood cell that makes your blood clot. They also play a role in healing.

Doctors may use platelet-rich plasma (PRP) on injuries or damage to tendons, ligaments, muscles, joints, and skin.

To collect plasma, a doctor draws blood from your body and uses a machine to separate the platelet-rich plasma from the rest of the blood. Then the doctor numbs the area of your body being treated with PRP injections. Once you’re numb, the doctor uses a needle to inject your plasma into the area of your body being treated.