That’s the chief finding of a new study by Rice University's Baker Institute for Public Policy. While most players receive treatment within the United States, several have traveled abroad for therapies unavailable domestically and may be unaware of the risks involved, researchers found.
 

"With the rise of new and unproven stem cell treatments, the NFL faces a daunting task of trying to better understand and regulate the use of these therapies in order to protect the health of its players," said Kirstin Matthews, an expert on ethical and policy issues related to biomedical research who led the study, published as a special supplement to the journal Stem Cells and Development.
 

Each year, more than 700 stem cell clinics around the world open their doors to "stem cell tourists," according to the paper's authors. Patients travel abroad to seek treatment for ailments ranging from autism to multiple sclerosis and paralysis — conditions for which no cure exists and treatment options are limited.
 

But the use of stem cells as orthopedic therapies is becoming more common and has drawn the attention of elite athletes, most notably NFL players, who have been vocal about receiving stem cell treatments and their successful recoveries.
 

According to the new research, 12 NFL players have been identified publicly as having received an unapproved stem cell treatment since 2009.
 

The paper notes that while unproven stem cell treatments in U.S.-based clinics rarely have severe side effects, they also arguably have little to no appreciable therapeutic benefits.
 

The researchers called on the NFL to devote funds for research on stem cell therapies and evaluate the safety and success of previous studies.