What it is
Bone marrow aspirate concentrate, often shortened to BMAC, starts with bone marrow drawn from a person's own body, commonly from the hip bone (pelvis). The liquid marrow is then processed in a centrifuge, a device that spins samples to separate their parts, to create a more concentrated product.
The resulting concentrate contains a mix of components, which may include blood cells, platelets, signaling proteins and a small number of cells sometimes called bone marrow stem cells or progenitor cells. The exact makeup varies from person to person and by the system used to prepare it.
BMAC is often described as 'bone marrow stem cell injection,' but that phrase can be misleading. In the U.S., the only FDA-approved stem-cell products are cord-blood-derived hematopoietic progenitor cell (HPC) products for certain blood and immune disorders, used in specialist transplant settings. BMAC for uses such as joint injections is not an FDA-approved product, and the FDA has warned the public about unapproved stem cell products.
How it’s traditionally been approached
Bone marrow has long been studied in medicine. Bone marrow transplantation, a specialist procedure for certain blood and immune conditions, is a well-established and separate practice from the concentrate injections discussed on many clinic websites.
BMAC has been explored by some orthopedic and sports medicine clinicians as an investigational option for joint, cartilage and tendon concerns, including a bmac injection knee approach. In these settings it is typically considered after more conventional options have been discussed, and the evidence is described as limited and still developing.
Because BMAC is usually made and used on the same day from the person's own marrow, it is often grouped with other so-called orthobiologics, such as platelet-rich plasma (PRP). Different clinicians hold different views on where, if anywhere, it fits, and research continues.
How the right provider may help
A good first visit is usually a conversation and an evaluation, not a sales pitch. A licensed clinician may review your history, examine the area of concern, look at imaging, and talk through conventional options first. Whether any procedure is appropriate is a decision for that clinician after an evaluation.
If BMAC comes up, the right provider may explain how the marrow is collected, what a typical bmac procedure recovery can look like for your situation, and what the realistic unknowns are. Recovery varies by person and by what is done, so ask your clinician rather than relying on general claims. A trustworthy provider will not promise results.
Useful questions to bring: Is this product FDA-approved for my condition? Is this part of a study registered on ClinicalTrials.gov with IRB oversight? Is my clinician's license active with the state medical board? What are the risks, the alternatives and the options if I decide not to proceed? Ask for written informed consent covering risks and alternatives. For bmac vs prp, ask what each is, how they differ, and why one might be suggested for you.
The whole-person view
Body, mind and stress affect each other. Ongoing joint pain can disrupt sleep, mood and activity, and stress and worry can in turn make discomfort feel more intense. Looking at the whole person, including movement, rest, support and emotional wellbeing, is a reasonable part of any health conversation.
Some people find body-based support such as Somatic Experiences helpful for tuning into how stress is held in the body, and others value talk therapy through Therapists.plus when pain or uncertainty about treatment feels heavy. These are complementary supports, not substitutes for medical care, and Providers.plus can help you find licensed providers.
Somatic Experiences: embodiment and movement →Therapists.plus: mind body connection →
Keep in mind
- In the U.S., the only FDA-approved stem-cell products are cord-blood-derived HPC products for certain blood and immune disorders; BMAC, clinic stem-cell, adipose, umbilical cord, Wharton's jelly and exosome products used for injections are not FDA-approved, and no exosome product is FDA-approved.
- Red flags include cure-all or 'treats everything' claims, paying to join a 'clinical trial', testimonials in place of evidence, and pressure to travel abroad or across states. 'Holistic' or 'alternative' framing never changes FDA status.
- Verify the clinician's license with your state medical board, confirm any study on ClinicalTrials.gov, and get written informed consent before any procedure.
- Licensed professionals should guide care for serious conditions. For emergencies call 911; in a crisis call or text 988.
Guides in this topic
Provider types
Frequently asked questions
What is bone marrow aspirate concentrate?
Bone marrow aspirate concentrate (BMAC) is a preparation made by drawing bone marrow from a person's own body, often the hip, and spinning it in a centrifuge to concentrate certain components. It may contain blood cells, platelets, signaling proteins and some progenitor cells. It is investigational for most uses and not a guaranteed treatment.
Is BMAC FDA approved?
No, BMAC used for injections such as in joints is not an FDA-approved product. In the U.S., the only FDA-approved stem-cell products are cord-blood-derived hematopoietic progenitor cell (HPC) products for certain blood and immune disorders, and the FDA has warned the public about unapproved stem cell products. Ask your clinician about the regulatory status of anything offered to you.
What is a BMAC injection in the knee?
A BMAC injection in the knee is an investigational approach in which concentrated bone marrow from the person's own body is injected into or around the joint by a clinician. Evidence for it is limited, and it is not FDA-approved for this use. A licensed clinician must evaluate you to decide whether any procedure is appropriate.
What is BMAC procedure recovery like?
BMAC procedure recovery varies from person to person and depends on the clinician's approach and the area treated. Because marrow is collected and an injection is given, people often ask about soreness and activity limits. Ask your clinician what to expect for your situation and what warning signs should prompt a call.
What is the difference between BMAC and PRP?
BMAC comes from bone marrow, while platelet-rich plasma (PRP) is made from a blood draw that is concentrated for platelets. They are different preparations with different collection steps. Neither is guaranteed to work, so ask a licensed clinician how each is regulated and which, if either, fits your situation.
Is a bone marrow stem cell injection safe?
A bone marrow stem cell injection carries risks like any procedure, and because most such products are not FDA-approved, safety and effectiveness are not established the way they are for approved treatments. Ask for written informed consent covering risks and alternatives, confirm the clinician's license, and check whether any study is registered on ClinicalTrials.gov with IRB oversight.
Educational resource. StemCell.biz shares general information and connects people with independent providers. It is not medical advice, diagnosis or treatment. Talk with a licensed professional about your health.