Platelet-rich plasma, or PRP, is a substance that’s thought to promote healing when injected. Plasma is a component of your blood that contains special “factors,” or proteins, that help your blood to clot. It also contains proteins that support cell growth. Researchers have produced PRP by isolating plasma from blood and concentrating it.
The idea is that injecting PRP into damaged tissues will stimulate your body to grow new, healthy cells and promote healing. Because the tissue growth factors are more concentrated in the prepared growth injections, researchers think the body’s tissues may heal faster.
The treatment hasn’t been definitively proven. It also hasn’t been approved as a treatment by the U.S. Food and Drug Administration. However, famous athletes like Tiger Woods and tennis star Rafael Nadal have been known to use these injections to help heal injuries.
Researchers are trying out PRP injections across a number of applications. Examples of these include:
Hair loss: Doctors have injected PRP into the scalp to promote hair growth and prevent hair loss. According to, which is also known as male pattern baldness.
Tendon injuries: Tendons are tough, thick bands of tissue that connect muscle to bone. They are usually slow to heal after an injury. Doctors have used PRP injections to treat chronic tendon problems, such as tennis elbow, Achilles tendonitis at the ankle, and jumper’s knee, or pain in the patellar tendon in the knee.
Acute injuries: Doctors have used PRP injections to treat acute sports injuries, such as pulled hamstring muscles or knee sprains.
Postsurgical repair: Sometimes doctors use PRP injections after surgery to repair a torn tendon or ligaments (such as the anterior cruciate ligament, or ACL).
Osteoarthritis: Doctors have injected PRP into the knees of people with osteoarthritis. A 2015 study found that PRP injections were more effective than hyaluronic acid injections (a traditional therapy) for treating osteoarthritis. However, the trial was a small group of 160 people, so larger trials are needed for this to be conclusive.
How do you prepare for PRP injections?
Generally speaking, there are few steps to preparing for PRP injections.
However, PRP can be injected in different ways. For example, sometimes a topical numbing lidocaine solution is applied to your scalp before injection. You may have to arrive early to a treatment session for this to be applied.
Other times, a local anesthetic is mixed with the PRP to reduce any discomfort. Sometimes, your doctor will inject or apply PRP during surgery. In this instance, preparation for PRP injections would involve following your surgeon’s recommendations presurgery.
PRP injection process
Here’s what to expect from a typical PRP injection process:
Because PRP involves injecting a substance into the skin, there are potential side effects. PRP is autologous, which means it contains substances that come directly from your own body. This reduces the risks for an allergic reaction that can occur from injecting other medications, such as cortisone or hyaluronic acid. However, there are risks from the injection itself, including:
When PRP is injected following injury, your doctor may recommend that you rest the affected area. However, these recommendations are more related to the injury and less to the PRP injections. Most people can continue their daily activities following PRP injections.
Because PRP injections are intended to promote healing or growth, you may not notice an immediate difference after receiving the injections. However, in several weeks or months, you may observe that the area is healing faster or growing more hair than you would have expected if you hadn’t received PRP injections.