The Cells That Find the Damage.

Muse cells are rare, naturally occurring stem cells.^⁠1,39 In laboratory and animal studies they travel toward injured tissue and become the cell types it needs.^⁠16,24,25 Small early trials in people have been encouraging, and larger studies are still needed.^⁠34,39

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Every claim on this site links to its published source.

Every status labeled. Sources include PNAS, Circulation Research and Stem Cells Translational Medicine. Last reviewed September 25, 2026.

Illustration, not a micrograph.

How Muse Cells Behave

Four things researchers have observed. The illustration behind the text changes as you read. It is an illustration, not a micrograph, and so are the panel images. Real micrographs, credited, are on the Science page.

Illustration: six glowing blue cells stay whole while smaller gray cells around them shrivel and break into fragments. — Illustration.

Panel 1. They Endure Stress

Their full name is multilineage-differentiating stress-enduring cells. In the lab, a long exposure to a digestive enzyme leaves a population enriched for Muse cells, because they tolerate that stress.^⁠3 They also withstood DNA damage better than other stromal cells.^⁠15 Scientists recognize them by a surface marker called SSEA-3 Stage-specific embryonic antigen 3, a sugar-based marker on the cell surface. Scientists use it to find and sort Muse cells..^⁠1

Evidence: Laboratory

Illustration: a line of glowing blue cells travels along a winding, transparent vessel toward a warm orange glow of injured tissue. — Illustration.

Panel 2. They Follow a Damage Signal

Injured tissue releases a signaling molecule called S1P Sphingosine-1-phosphate, a small fat-based signaling molecule released by damaged cells. It can act like a distress flare.. In rabbit and mouse studies, Muse cells injected into a vein sensed it and gathered at the injury.^⁠16,17 Human trials have not yet tracked where the cells go.^⁠39

Evidence: Animal studies

Illustration: one glowing blue cell linked to three different cell types: a branching nerve cell, a long spindle-shaped muscle cell and a many-sided liver cell. — Illustration.

Panel 3. They Become What the Tissue Needs

In the lab, a single Muse cell can give rise to cells of all three Three germ layers The three basic tissue layers of the early embryo (ectoderm, mesoderm and endoderm). They give rise to every organ, from skin and nerves to muscle, bone and gut., the three families every tissue comes from.^⁠1 In a rabbit heart attack model, Muse cells that reached the damaged heart took on features of heart muscle cells.^⁠16

Evidence: Laboratory and animal studies

Illustration: a gloved hand holds a small, unlabeled glass vial of pale liquid in a softly blurred laboratory. — Illustration.

Panel 4. They Have Entered Early Human Trials

From 2018 to about 2022, eight registered trials in Japan tested one donor Muse cell product, CL2020 The development code for the donor Muse cell product made by Life Science Institute, Inc. and used in the Japanese clinical trials. All published human trial results for Muse cells come from this one product., in stroke, heart attack, spinal cord injury, ALS and other conditions.^⁠38,40 In the only randomized, placebo-controlled trial, 40 percent of stroke patients given CL2020 could manage daily life without help at 12 weeks, compared with 10 percent on placebo.^⁠34 Encouraging, and small: larger controlled studies are still needed. See every trial.

Evidence: Early human trials (one small controlled trial)

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Where the Research Stands

Promising, early, and honest about both. Every number below links to its source.

First described, at Tohoku University in Japan: 2010^⁠1
Share of bone marrow mononuclear cells that were Muse cells in the first count: 0.04%^⁠1
Germ layers a single cell can form in the lab: 3^⁠1
Registered clinical trials of one product, CL2020, in Japan from 2018: 8^⁠40

What the Trials Show

57 people received CL2020 in six published early trials. No trial was stopped for safety, and investigators judged nearly all serious medical events unrelated to the cells. Serious events did occur, and one seizure in the stroke trial could not be ruled out as related.^{⁠32,33,34,35,36,38,39}

What Is Still Unknown

No Muse cell product has been approved by the FDA, Japan’s PMDA or, as far as we know, any other regulator. The developer stopped the CL2020 program in 2023 for business reasons, stating no safety or efficacy concern, and the rights returned to the cells’ discoverer, Prof. Mari Dezawa, and Tohoku University. Larger, longer, controlled studies are the next step.^{⁠53,54,59,73}

Ask a Question See Every Trial and Its Status

Dr. Pradeep Albert, smiling with his arms crossed, wearing a dark suit jacket over a blue and white striped shirt with an open collar.

Who Prepared This Guide

Dr. Pradeep Albert is a longevity expert and regenerative medicine specialist, and Co-founder and President of the American Academy of Peptide Medicine. He follows the published research on Muse cells closely and created this site to explain it in plain language, with every claim linked to its source.

Disclosure. Dr. Albert is CEO of Vesalius Longevity Labs, which has financial ties to MuseCell Innovations, a company in the Muse cell field. This site sells nothing and does not link to any company’s products.

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Questions People Ask

Plain answers, with sources, to the questions that come up most.

All Questions

Is any Muse cell treatment approved?

No. No Muse cell product has been approved by the FDA, Japan’s PMDA or, as far as we know, any other regulator.^⁠53,73 The most advanced program, a donor cell product called CL2020, was tested in small trials in Japan. Mitsubishi Chemical Group discontinued it in February 2023 for business reasons and stated no safety or efficacy concern.^⁠54,55

Since July 2026, Muse cell products have been offered through private providers in four U.S. states. The company that licenses them states they have not been evaluated or approved by the FDA.^⁠61,63 Results from the CL2020 trials do not show whether any other product is safe or works.^⁠39,62

If you are considering any stem cell treatment, talk with your own physician, and look for registered clinical trials on ClinicalTrials.gov (opens in a new tab). A listing there is not a review by the FDA, and some listed studies only follow people who obtain products at private clinics.

Could Muse cells help my condition?

A Muse cell product, CL2020, has been tested in small early trials for heart attack, stroke, spinal cord injury, ALS, a severe blistering skin disease and brain injury in newborns, and other organs have been studied in animals.^⁠38,40 These results are not enough to show that Muse cells help any condition, and no product is approved.^⁠39,53

This site cannot give medical advice. Your own physician is the best person to ask, and ClinicalTrials.gov (opens in a new tab) lists registered studies. A listing there is not a review by the FDA, and some listed studies only follow people who obtain products at private clinics. See the areas under study.

Are Muse cells safe?

57 people received CL2020 in six published early trials. No trial was stopped for safety, and investigators judged nearly all serious medical events unrelated to the cells. Serious events did occur, including two deaths judged unrelated, and one seizure in the stroke trial could not be ruled out as related.^{⁠32,33,34,35,36,38,39}

No tumors have been attributed to Muse cells in animal studies or in the small human trials so far.^⁠1,38,39 Follow-up lasted 12 weeks to about 18 months, and trials this small cannot detect rare harms, so long-term safety still needs larger, longer studies.^⁠39

Who is behind this site, and is anything for sale?

This site was prepared by Dr. Pradeep Albert, a longevity expert and regenerative medicine specialist, to explain published Muse cell research in plain language. It sells nothing and does not link to any company’s products.

Have a Question About Muse Cell Research?

Ask about the science, the trials, or what the evidence does and does not show. Dr. Albert’s team will read it and reply by email.