What Is Stem Cell Therapy? A Plain-Language Guide

What are stem cells, in plain language?

Stem cells are the body's raw building blocks. They have two defining abilities: they can renew themselves, and they can develop (differentiate) into more specialized cells, such as cartilage, bone, muscle, or tendon cells. Think of them as a repair kit that your body keeps on hand to maintain and rebuild tissue.

Adults carry stem cells throughout their bodies, with meaningful concentrations in bone marrow and in adipose (fat) tissue. Regenerative medicine clinics collect cells from these sources, prepare them in a clinical setting, and deliver them back into the area that needs support, usually through a guided injection.

How do regenerative clinics use stem cells?

Most regenerative therapy performed in US clinics is autologous, which simply means the cells come from your own body. A common approach is bone marrow aspiration: a clinician draws a small sample of marrow, concentrates it in a centrifuge, and injects the prepared concentrate into a joint, tendon, ligament, or spinal area. A similar technique processes cells from a small amount of your own fat tissue.

Clinics may also use platelet-rich plasma (PRP), a related cell-based therapy that concentrates the platelets and growth factors from your own blood to support healing in the target area. PRP and cell therapy are often part of the same regenerative treatment plan, and the right choice depends on your condition, your anatomy, and your goals.

What is FDA-approved today?

This is the most important thing to understand, and a trustworthy clinic will explain it openly. In the United States, the only stem cell treatments with routine FDA approval are blood-forming (hematopoietic) stem cell transplants, used for decades to treat certain blood cancers and immune disorders, along with a small number of newer cellular therapy approvals for specific pediatric conditions.

Nearly every other use of cell-based therapy, including injections for joint pain, tendon injuries, and back pain, is considered investigational and has not been cleared by the FDA for those conditions. The FDA has repeatedly warned that unapproved stem cell products marketed with miracle claims can be unsafe. Responsible clinics treat patients within their professional medical judgment, are transparent about the evidence, and never promise outcomes they cannot deliver.

“Currently, the only stem cell products that are FDA-approved for use in the United States consist of blood-forming stem cells (also known as hematopoietic progenitor cells) that are derived from umbilical cord blood.”

Questions to ask before any stem cell treatment

• Where do the cells come from, and are they my own cells?
• Who performs the procedure, and what are their qualifications?
• What does the scientific evidence show for my specific condition?
• Is this treatment FDA-approved or investigational?
• What are the possible risks and side effects?
• What are the full costs, and is there any insurance coverage?
• What does aftercare and follow-up look like?