• Posted May 13, 2026

Ivermectin Prescriptions Doubled After Mel Gibson Cancer Cure Claim

Prescriptions for the anti-parasite medication ivermectin doubled after actor Mel Gibson endorsed the dewormer as an off-label cancer cure on a high-profile podcast, a new study says.

Gibson appeared on "The Joe Rogan Experience" in January 2025 and described three friends with stage 4 cancer who he said recovered after taking ivermectin and fenbendazole, another dewormer that’s approved only for veterinary use.

Ivermectin prescriptions leapt by 97% in the United States in the six months following Gibson’s endorsement, compared to the year before, researchers reported May 12 in JAMA Network Open.

Ivermectin and drugs like fenbendazole have shown anti-cancer activity in lab tests and animal studies, but no clinical trials have shown they are safe and effective for treating cancer in humans, researchers said.

“Not all widely shared health information is accurate, even when it comes from familiar or influential sources,” researcher Dr. Katherine Kahn, a professor of medicine at the David Geffen School of Medicine at UCLA, said in a news release.

“Using unproven treatments can carry real risks, especially if it delays care that is known to work,” she said. “Clinicians and health systems play a critical role in helping patients navigate information and make informed decisions.”

Ivermectin first came to prominence during the COVID-19 pandemic, when influencers touted it as a potential treatment for the respiratory virus. These claims were never validated, and the National Institutes of Health does not recommend its use against COVID, according to Drugs.com.

For the study, researchers tracked electronic health record data for more than 68 million patients treated by 67 health care organizations from all regions of the United States.

Results showed that ivermectin prescribing rates were more than 2.5 times higher among people with cancer following Gibson’s remarks compared to the year before.

In the South, ivermectin prescription rates more than tripled levels of the year before, researchers found.

Increases in ivermectin prescriptions were 2.8 times higher in men than in women, and almost 2.7 times higher in younger adults 18 to 64 than in those 65 and older, the study says.

“As a primary care doctor, I want my patients and people across the country to have the chance to get treatments we know can help them live longer, healthier lives," senior researcher Dr. John Mafi said in a news release. He’s an associate professor-in-residence of medicine at UCLA.

“When prescribing for an unproven cancer treatment more than doubles after a single podcast, especially among men and people in the South, it raises a concern that patients may be skipping or delaying treatments we know work in favor of something that hasn't been proven to help them,” Mafi said.

These results show how quickly shaky medical claims can spread, particularly if promoted by someone with celebrity status, researchers said.

“We often focus on how to efficiently get evidence into practice,” said lead researcher Michelle Rockwell, an assistant professor of family and community medicine at Virginia Tech in Roanoke, Virginia.

”But these findings remind us that some forces can influence care very quickly,” Rockwell said in the news release. “The challenge for health systems is how to meet patients in that moment with information that is both timely and trustworthy.”

More information

Harvard Medical School has more about cancer misinformation.

SOURCES: UCLA, news release, May 12, 2026; JAMA Network Open, May 12, 2026