As rock legend Ozzy Osbourne has turned to stem cell therapy, some experts caution that it’s not for everyone.

At the start of his latest episode of "Ozzy Speaks" on SiriusXM with Billy Morrison, Osbourne revealed that he recently returned from a follow-up appointment "after having some stem cells put in me."

The rocker also had a previous treatment approximately three months ago, as he stated in the episode.

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"The thing is, you have it, and you go, ‘I don't feel that great,’ but I don't know what it would be like if I didn't have it," Osbourne said.

In the past several years, the musician has struggled with several serious medical problems that have impacted his mobility, including Parkinson’s disease, per a report.

Ozzy Osbourne stem cells

Rock legend Ozzy Osbourne has turned to stem cell therapy — but some experts are cautioning that it’s not for everyone. (Getty Images/iStock)

After he first started stem cell treatment in 2020, he wanted "to be a part of the world again," his daughter Kelly Osbourne said in a report at the time.

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"Seeing, after one treatment of stem cell, what has happened and the progress that he’s made is mind-blowing," she added.

Fox News Digital reached out Ozzy Osbourne for comment. 

Below is an overview of the treatment — and what to know about the risks and benefits.

What are stem cells?

Stem cells are found in almost every tissue in the body, according to the Mayo Clinic website.

Some stem cells repair tissues after injury, while others have the potential to become different types of cells, such as brain cells, muscle cells in the heart or bone cells.

"We routinely use cellular therapies, including stem cells, to treat cancers of the blood and bone marrow," Dr. Mikkael Sekeres, chief of the division of hematology of Sylvester Cancer Center at the University of Miami, told Fox News Digital.

Stem cell operation

Some stem cells repair tissues after injury — while others have the potential to become different types of cells, such as brain cells, muscle cells in the heart or bone cells. (iStock)

"The theory is, we can give high doses of chemotherapy to people who have these cancers to eliminate the cancer, but those therapies may have such a high dose that we could wipe out the healthy cells in the bone marrow," he said.

Alternatively, the doctor went on, experts can "rescue" the bone marrow by giving stem cells to a patient from a healthy donor.

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Another advantage is that the healthy donor stem cells will produce a new immune system to attack and eliminate any remaining cancer, Sekeres added.

"Use of stem cells in this way has saved tens of thousands of lives," he noted.

Therapies ‘largely experimental’

Stem cell therapies are only approved by the U.S. Food and Drug Administration (FDA) to treat certain cancers of the blood and immune system, according to the Centers for Disease Control and Prevention (CDC). 

In 2023, the FDA also approved a cord blood-based cell therapy to decrease the risk of infection after stem cell transplants.

Ozzy Osbourne seen out for the first time

Ozzy Osbourne is seen for the first time in this image since announcing he was canceling his tour due to medical concerns. (MEGA for Fox News Digital)

"Stem cell therapy given for other reasons is largely experimental and unproven," Sekeres noted.

Despite its potential benefits, stem cell therapy isn’t considered a "silver bullet" for Parkinson’s disease treatment, according to Dr. Michael S. Okun, a Florida-based medical advisor to the Parkinson’s Foundation. 

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"Though there have been many advances in stem cell technology, the realization that Parkinson’s is a disease of more than just dopamine underscores the importance of multidisciplinary treatment," Okun, who is also the executive director of the Norman Fixel Institute for Neurological Diseases University of Florida Health in Gainesville, Florida, told Fox News Digital.

All stem cell products require the FDA’s approval, according to the agency’s website.

"Folks interested in Parkinson’s stem cell therapy should be cautious if ever offered a treatment," Okun said.

Stem cell therapy

Despite its potential benefits, stem cell therapy isn’t considered a "silver bullet" for Parkinson’s disease treatment, a doctor warned.  (iStock)

"We recommend requesting a copy of the institutional review board approval, which is a document verifying that investigators have been authorized to perform research in a human population."

(An institutional review board ensures ethical treatment of research subjects.)

"Since stem cell therapy is still investigational, you should never be charged to participate in a research trial," Okun noted.

"Folks interested in Parkinson’s stem cell therapy should be cautious if ever offered a treatment."

"There is a large market for ‘stem cell tourism,’ in which people may be charged large sums of money, and in some cases irreversible side effects may follow a transplant."

Potential adverse side effects

One type of stem cell therapy is a stem cell transplant, which involves infusing another person’s stem cells into the recipient’s body.

Sometimes these stem cells come from the bone marrow, which is known as a bone marrow transplant, according to experts.

In other cases, they are harvested from a baby’s umbilical cord, which is known as a cord blood transplant.

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Some people may experience symptoms of rejection if their immune system recognizes the donor stem cells as "foreign" and starts to attack them.

Acute symptoms may include an itchy rash, diarrhea, general malaise, shortness of breath and yellowing of the eyes, according to the National Health Service.

Lab research

All stem cell products require the FDA’s approval, according to the agency’s website. (iStock)

Longer-term complications may include infertility, various cancers, cataracts, bone or muscle weakness, and damage to certain organs, such as the liver, kidney, lung or heart, per the National Cancer Institute’s website.

Stem cell therapy should not be viewed as a "fountain of youth," Sekeres cautioned.

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Previous research published in JAMA Network Open discovered a multi-bacterial outbreak among patients who received unapproved products that were marketed as stem cell therapies, he pointed out.

To verify that a therapy is FDA-approved, the agency recommends emailing ocod@fda.hhs.gov for information, according to its website.

Fox News Digital reached out to the FDA for further comment. 

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