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Why Are Stem Cells Collected From Fat Rather Than Bone Marrow?

Published 2026.10.10 7 min read

Hello, I am Dr. Hidenori Shimada of Grand Green Osaka Umekita Clinic in Osaka, Japan.

If you are reading about regenerative medicine, you may have noticed that mesenchymal stem cells (MSCs) can be taken from several parts of the body. Two of the most discussed sources are bone marrow and fat tissue. At Grand Green Osaka Umekita Clinic, adipose-derived stem cell therapy uses cells collected from a patient’s own fat. This article explains, in plain language, why fat is often chosen, what the research does and does not show, and what to ask a doctor before deciding anything.

The short answer

Fat tissue is generally reported to contain a larger number of mesenchymal stem cells per amount of tissue than bone marrow, and it can be collected through a small incision under local anesthesia. Bone marrow collection is usually considered a more invasive procedure. For these practical reasons, adipose tissue has become a common source in regenerative medicine. This does not mean that one source is proven to work better than the other for every condition, and the choice should always be discussed with a physician.

What mesenchymal stem cells are

Mesenchymal stem cells are a type of somatic stem cell. They can be found in fat tissue, bone marrow, and other tissues. In laboratory studies they can develop into fat, bone, and cartilage cells. They have also been reported to release anti-inflammatory substances and growth factors that may support the repair of damaged tissue. Research into these properties is active worldwide, but many findings come from laboratory or early-stage clinical studies, so results should be read with caution.

Because stem cell numbers and activity tend to decline with age, researchers have been interested in whether cells taken from a person’s own body could be expanded and returned to support tissues affected by aging or inflammation. Whether this is appropriate for any individual depends on that person’s health and condition.

Fat and bone marrow compared

Comparative reviews indexed in databases such as PubMed describe a few general trends. These are tendencies, not rules, and individual results vary with age, health, and laboratory methods.

Cell content: adipose tissue is reported to contain relatively abundant MSCs, while bone marrow contains fewer per sample.
Collection burden: fat can be collected with a small incision under local anesthesia, whereas bone marrow collection is generally more demanding for the patient.
Amount needed: only a small piece of fat, roughly the size of a few grains of rice, is described as necessary for culture and expansion.
Biological differences: cells from different sources may differ in their properties, and it is not established that one source is better for every purpose.

In other words, the preference for fat is largely about practicality and the burden of collection, supported by general observations about cell content, rather than a claim of superior outcomes.

How the process works in an adipose-derived approach

In the treatment offered at Grand Green Osaka Umekita Clinic, a very small amount of the patient’s own fat tissue is collected on an outpatient basis. The mesenchymal stem cells in that tissue are then cultured and expanded at a specialized facility, and the cells are returned to the patient by intravenous infusion. Because the cells come from the patient, the approach is called autologous. Autologous cells are generally considered to carry a lower risk of rejection than donor cells, although this does not remove all risks.

Infused mesenchymal stem cells have been reported to travel through the bloodstream and gather at sites of inflammation or damage, an effect often called homing. How much this matters in actual patients is still being studied, so it is best understood as a research concept rather than a promise of benefit.

Legal framework and self-pay care in Japan

In Japan, cell-based treatments of this kind are provided under the Act on the Safety of Regenerative Medicine, which requires a treatment plan to be submitted and reviewed before a clinic offers it. This is a framework for oversight, and it does not mean that a treatment is guaranteed to be effective. Adipose-derived stem cell therapy is a self-pay treatment that is not covered by national health insurance, so costs, the number of treatments, and the schedule need to be confirmed directly with the clinic.

Stem cell therapy is not a replacement for standard medical care. If you are being treated for a condition, continue to follow your current doctor’s advice and tell them if you are considering regenerative medicine.

What to confirm before a consultation in Osaka

Whether adipose-derived stem cell therapy is suitable for you can only be judged by a doctor after an examination and a review of your medical history. Preparing questions in advance can make that conversation more useful. Consider asking:

Why is fat tissue used as the cell source in your clinic, and what is the evidence for your intended use?
What are the possible risks and side effects of both the fat collection and the infusion?
How are the cells cultured and checked, and where does this take place?
What are the total costs, the number of infusions, and the expected treatment period?
Is this treatment appropriate given my current conditions and medications?
What follow-up is available after treatment?

Grand Green Osaka Umekita Clinic is located in Umeda, Osaka, and provides information pages for international patients, so you can review the basics in English before you visit. Overseas patients should also think through travel timing, because collection, culture, and infusion take place on separate visits.

Summary

Fat is commonly used as a source of mesenchymal stem cells because it is reported to contain abundant cells and can be collected with a smaller burden than bone marrow. These are general trends rather than proof of better results, and the evidence varies by condition. Adipose-derived stem cell therapy is a self-pay treatment provided under Japan’s regenerative medicine law, and its suitability, costs, risks, and side effects must be confirmed with a doctor during a consultation. If you are considering this option, prepare your questions and your medical history, and take the time to compare information before making a decision.

Fat vs bone marrow

Fat tissue

Reported abundant MSCs
Small incision, local anesthesia
Small amount needed

Bone marrow

Reported fewer MSCs
Heavier collection burden
Another established source

This figure is a conceptual summary of the article. Please consult a doctor

Learn more about Adipose-Derived Stem Cell Therapy

References

Supervising Physician

Director, Medical Corporation Shimada Clinic
Head of Clinical Practice, Grand Green Osaka Umekita Clinic

Hidenori Shimada

Graduated from the University of Tokushima Faculty of Medicine in 2005. After his initial residency, he obtained U.S. medical certification (ECFMG) and trained as a sub-intern in general surgery at the University of Washington. After completing the doctoral program at Kyoto University Graduate School of Medicine and working as a researcher at the Center for iPS Cell Research and Application (CiRA), Kyoto University, he founded Shimada Clinic in 2013. At Grand Green Osaka Umekita Clinic (https://umekitaclinic.org), he is engaged in a wide range of care, from internal medicine and pediatrics to cell therapy and aesthetic medicine.

* The physician supervision of this article covers its academic content only and does not constitute a recommendation of any specific treatment or product.

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