Synthetic Chemical From Bears Could Stall Onset of Diabetes

Photo of a black bear cub climbing a tree.
A black bear cub climbs a tree in Yellowstone National Park in the United States. Photograph by Gavriel Jecan, Corbis.

The American Association for the Advancement of Science wrote about the connection between TUDCA and bear bile in its press release concerning type 1 diabetes. The association has since removed this reference. Bear bile has a historical and contextual relationship to the research discussed within this article, and our story is still accurate as it stands.

Harvard scientists have discovered a chemical in bear bile that may slow the development of type 1 diabetes, according to a study published in the journal Science Translational Medicine. However, researchers condemn the farming of bears for bile and suggest that a synthetic version of the bile be used. 

The bitter, yellow-green liquid drained from the gallbladder of a bear is a common ingredient in many traditional Chinese medicines, and proponents believe it cures everything from liver disease to epilepsy.

“The gallbladder of the bear was one of the most valuable voodoo medicines that people used, especially in China,” said Gokhan Hotamisligil, a geneticist at Harvard University School of Public Health.

“It almost made the black bear extinct [in China]. It started illicit harvesting and trafficking of bear gallbladder.” (See “Endangered Moon Bears Harvested for Bile in Vietnam.”)

The remedy has been prescribed for centuries—the first known medicinal reference to bear bile was recorded in A.D. 659 —and it’s still used controversially today. “Some 10,000 bears are farmed in China to procure their bile for traditional Chinese medicine,” according to a 2012 letter published in the journal Nature, often in inhumane conditions.

Hotamisligil said he condemns the practice.

“Our work should be used as strong evidence against the use of bear bile for any scientific or medical purpose,” he said in a written statement issued by an animal rights group in response to this article. “…Any alternative sources, including synthesis, exist that does not involve this cruel approach.”

Treating Diabetes

No bears were harmed in the making of Hotamisligil’s study, published in the journal Science Translational Medicine. You can get bear bile-like chemicals from other types of animals like oxen. Hotamisligil purchases it from a company that harvests it out of livestock. He’s using the unappetizing stuff in an attempt to resolve what he calls “the biggest global threat to health.”

“We believe in 25 years there will be in the range of half a billion people in the world with diabetes,” he said. “The magnitude of the problem is intense. We’re going to face a huge problem if we don’t deal with this.”

There are two types of diabetes, type 1 and type 2. Type 1 diabetes happens when the immune system attacks and maims beta cells, which help produce insulin. Insulin regulates your blood sugar, which ebbs and flows depending on what you eat. Without it, your blood sugar can spike or drop so quickly that you go into a coma. In people with type 2 diabetes, the pancreas may produce insulin, but their bodies don’t respond to the hormone.

Type 1 diabetes is mostly a problem for children, who usually develop the disease in their early years up until young adulthood. Bile is rich in a chemical called TUDCA, which stands for tauroursodeoxycholic acid. The substance appears to shield the beta cells in mice models from immune system attack.

“If we give animals [TUDCA before they] become diabetic, they never become diabetic,” Hotamisligil said.

Their beta cells do not succumb to attacks from the body’s immune system, and they continue to produce insulin, he added. “There is a very dramatic protection.”

Waiting for a Disease

Scientists have the ability to identify children who are at risk for developing type 1 diabetes, but right now, there’s nothing they can do with the information but wait for symptoms to develop. If bear bile is effective in humans, it could potentially slow or even halt the progression of this life-changing illness.

In higher concentrations, the bile might even help people at risk for type 2 diabetes, Hotamisligil said.

“The research is important because it shows the use of a very safe drug that could be used to either prevent or slow the onset of the disease,” said Rudy Leibel, a molecular geneticist at the Columbia University Medical Center in New York City who was not involved in the research.

The Harvard scientist has given himself a tight timeline. His team tried hundreds of thousands of molecules before settling on bear bile in 2004. Now Hotamisligil wants to move to human trials in no more than a year and a half. Because bear bile is already FDA-approved for clinical use, Hotamisligil’s goal might not be out of reach.

“The funding for biomedical research has been cut, [but] we will find resources one way or another and start a trial,” Hotamisligil said. “We’ll initiate this in humans.”


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Meet the Author
Mollie Bloudoff-Indelicato is a science journalist who loves em dashes, ’80s music and parasites. She has a master’s degree from the Columbia University Graduate School of Journalism with concentrations in science journalism, photography, and radio reporting. Contact her at, and follow her on Twitter at @mbloudoff.