Though researchers have been studying the animal deworming drug ivermectin for decades, there is no evidence that it’s a safe or effective way to treat cancer in people.

However, a June 2026 study put the topic back in the spotlight. After being downloaded more than 85,000 times before its official publication, the study gained traction on social media – particularly X – and within alternative health communities, where it was shared widely to bolster broader claims about repurposing antiparasitic drugs as cancer treatments. While traditional news outlets were covering renewed public interest in ivermectin for cancer following the COVID-19 pandemic, much of the conversation surrounding this particular new study unfolded outside of mainstream media coverage.

Shortly after the study was published, scientists raised serious concerns about how the study arrived at its findings, conflicts of interest and the peer-review process.

For one, the study did not have a comparison group to determine whether patients taking a combination of ivermectin and another antiparasitic truly saw improvements due to these drugs or the conventional cancer therapies they were also taking. Moreover, the study relied on patients’ own self-reports rather than medical record information. Unlike medical records, self-reports cannot be independently verified and are more susceptible to bias, making them less reliable as scientific evidence.

Although the journal issued an Expression of Concern shortly after publication, the study has not yet been retracted.

This case illustrates a recurring challenge in how science reaches the public. Early findings can spread quickly through news coverage, social media and online communities, while the evidence needed to fully evaluate them can take months or years to develop. By the time additional evidence emerges, many people have already shared the original report or made financial and medical decisions based on it.

As a health communication researcher, I study how people interpret new cancer information, how health misinformation spreads and how communication can support good health behaviors.

The renewed attention surrounding ivermectin and other antiparasitic drugs offers an opportunity to understand why some scientific findings become influential before researchers fully understand what they mean.

Why ivermectin keeps returning

Repurposing........

© The Conversation