What Are MUSE Cells? A Physician's Guide
BLUF: MUSE cells (Multilineage-Differentiating Stress-Enduring cells) are a naturally occurring subpopulation of adult mesenchymal stem cells identified by the surface marker SSEA-3. Discovered in 2010 by Dr. Mari Dezawa at Tohoku University, they are notable for being pluripotent-like without tumor risk, immune-privileged, and capable of homing to sites of tissue damage — properties that distinguish them sharply from conventional mesenchymal stem cells (MSCs).
Where Do MUSE Cells Come From?
MUSE cells are not synthetic or engineered — they exist naturally in the human body. They were identified by Dr. Mari Dezawa and her team at Tohoku University in 2010 as a distinct population within bone marrow, peripheral blood, umbilical cord blood, and connective tissue. They represent roughly 1–3% of the mesenchymal stem cell pool and can be isolated using the surface marker SSEA-3 (stage-specific embryonic antigen-3) via fluorescence-activated cell sorting.
The name itself reflects their defining characteristic: these cells survive and activate in response to cellular stress — including the harsh, oxygen-poor, inflammatory conditions found in damaged tissue. Rather than dying or remaining dormant, MUSE cells mobilize under stress and migrate toward injury signals.
How Are MUSE Cells Different from Regular Stem Cells?
This is the question I hear most often from patients at Springs Rejuvenation who have already explored traditional stem cell options. As Dr. Charles Pereyra, MD, I explain it this way: most adult stem cells are multipotent — they can become a limited range of cell types within their tissue of origin. MUSE cells are pluripotent-like, meaning research suggests they may differentiate into cells from all three embryonic germ layers — ectoderm, mesoderm, and endoderm — while being derived from adult tissue rather than embryos.
Critically, unlike induced pluripotent stem cells (iPSCs) or embryonic stem cells, which carry a documented risk of teratoma formation, MUSE cells in published studies have shown no teratoma formation. The Dezawa laboratory's foundational papers and subsequent animal model studies have consistently reported this non-tumorigenic profile, which is why researchers and clinicians have been cautiously optimistic about their clinical potential.
Key Properties of MUSE Cells
Published research to date has characterized MUSE cells as having several notable properties:
- Pluripotent-like differentiation: Research suggests they may generate cells representative of all three germ layers under appropriate conditions.
- Non-tumorigenic: No teratoma formation has been observed in published studies, in contrast to iPSCs and ESCs.
- Immune privilege: MUSE cells appear to express low levels of MHC class II antigens, which may reduce the risk of immune rejection. Clinical trial protocols in Japan have not required immunosuppressant therapy.
- Homing ability: They express receptors (including S1PR2) that respond to sphingosine-1-phosphate (S1P), a lipid signaling molecule released by damaged tissue, allowing them to migrate toward areas of injury after intravenous administration.
- Stress endurance: Unlike most stem cells, MUSE cells maintain viability and function in hypoxic, inflammatory environments — the exact conditions found at injury sites.
- Paracrine effects: Once in damaged tissue, they may exert anti-inflammatory, anti-apoptotic, and anti-fibrotic effects through signaling molecules, in addition to direct differentiation.
What Does the Clinical Research Show?
MUSE cells are investigational. The most advanced clinical development has occurred in Japan, where Life Science Institute developed CL2020 — a MUSE-based product evaluated in trials for acute ischemic stroke, ALS, acute myocardial infarction, and spinal cord injury, among others. In the United States, Springs Rejuvenation sources authentic Dezawa-method MUSE cells prepared in an FDA approved lab for physician-supervised, off-label clinical applications. As of 2026, we are among the very few US-based practices with access to this supply.
Are MUSE Cell Protocols Right for Everyone?
Candidacy for any regenerative therapy requires an individualized evaluation. In my clinical practice, I assess each patient's overall health status, history, and goals before recommending any regenerative protocol. MUSE cell programs are not a replacement for standard-of-care medical care. If you are exploring whether MUSE cell therapy may be appropriate for your situation, I encourage you to schedule a consultation at one of our Springs Rejuvenation centers. You can also read our related articles on how MUSE cells differ from conventional stem cells and how MUSE cells work in regenerative medicine.
Frequently Asked Questions
Are MUSE cells FDA approved?
MUSE cell therapy is not an FDA approved therapy and is in the experimental stages in the United States. Springs Rejuvenation's cell preparations are produced in an FDA approved lab. Patients receive comprehensive informed-consent discussion before any procedure.
How are MUSE cells isolated?
Authentic MUSE cells are identified by the SSEA-3 surface marker and isolated using fluorescence-activated cell sorting (FACS) or stress-selection methods developed by Dr. Dezawa's laboratory. Not all products marketed as "MUSE cells" use this validated isolation protocol — provenance and methodology matter. See our article on why authentic MUSE cell sourcing matters.
Do MUSE cells require immunosuppression?
Based on published clinical trial data from Japan, MUSE cell administration has not required concurrent immunosuppressant therapy, which is a meaningful practical difference from some other cell-based approaches. This is believed to relate to their relatively low expression of MHC class II antigens.
Dr. Charles Pereyra, MD, is the medical director of Springs Rejuvenation, a physician-led regenerative medicine practice with locations in Miami/Aventura, New York City, Los Angeles, Austin, and Atlanta.
Disclaimer: Springs Rejuvenation's cell preparations are produced in an FDA approved lab, but are not an FDA approved therapy. This information is currently in the experimental stages — all information provided is based on our clinical experience and published research. These statements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease. Results may vary. Individual results depend on many factors. Always consult a qualified physician before beginning any regenerative protocol.