Prescriptions of Ivermectin for Cancer Doubled After Celebrity Podcast Endorsement

The impact of celebrity endorsements on prescriptions was confirmed in new research published in JAMA Network Open.¹ The prescribing rates of ivermectin-benzimidazole, a combination therapy used for parasitic infections, increased after Mel Gibson discussed the regimen as a form of cancer treatment on a podcast with Joe Rogan.

The combination of ivermectin and fenbendazole (a benzimidazole agent) was promoted as an off-label cancer treatment on the podcast “The Joe Rogan Experience” in January 2025.² Although there is no current clinical trial evidence for the use of this combination for cancer, with the National Cancer Institute only recently announcing plans for further study of ivermectin,³ the claims from the podcast spread across media platforms. This study aimed to assess how this celebrity endorsement affected prescription rates of ivermectin-benzimidazole from January 1, 2025, to July 31, 2025, and compare the rates to those in 2024.¹

The researchers used data from a multicenter research network that represented 67 health care organizations across the US. Prescriptions of the combination to patients aged 18 to 90 years in primary care, emergency department visits, or outpatient specialist from January 1, 2018, to July 31, 2025, were identified. Patients who had 1 or more prescriptions for ivermectin and 1 or more prescriptions for a benzimidazole on the same calendar day were considered as having been prescribed the combination.

Prescribing rates per 1000 patients were calculated in patients with 1 or more diagnoses of cancer. Rate ratios (RRs) were calculated to compare the monthly prescribing rates from January 1 to July 31, 2025, compared with the corresponding monthly rates in 2024 for patients living with cancer. The results were stratified by US census region, race, sex, and age.

There were 68,373,949 patients included in the study overall. The cohort saw prescribing rates that doubled from January 1 to July 31, 2025, compared with the same time period in 2024 (RR, 1.97; 99.5% CI, 1.70-2.29). Patients aged 18 to 64 years had a higher relative increase in prescribing compared with patients 65 years and older (RR, 2.12; 99.5% CI, 2.36-2.99 vs RR, 1.25; 99.5% CI, 0.91-1.59). Patients who identified as White also had higher prescribing rates compared with Asian, Black, or other races reported in the data set (RR, 2.61; 99.5% CI, 2.21-3.09 vs RR, 1.38; 99.5% CI, 1.03-1.73). The South census region had higher rates of prescription compared with other regions (RR, 3.12; 99.5% CI, 2.54-3.87 vs RR, 1.36; 99.5% CI, 1.01-1.72).

Patients with cancer had prescribing rates that were 2.5 times higher in 2025 compared with 2024 (RR, 2.63; 99.5% CI, 2.08-3.24). Men, patients aged 18 to 64 years, White patients, and patients in the South all had higher relative increases in prescribing in 2025.

There were some limitations to this study. Causality could not be established due to the observational design of the study. Cancer status could have been misclassified in the data. The prescription data only reflected orders rather than the dispensing of the medication. Whether a patient substituted the combination therapy for conventional cancer treatment was not assessed.

The study found that celebrities have a sizeable influence on the prescription rates of treatments that they endorse, affecting the rate of prescriptions in the months immediately following public discussion of the treatment.

“Since our 2003 publication demonstrating the immediate and enduring positive impact of the Katie Couric effect on colorectal cancer screening,⁴ we are well aware of the significant impact that celebrity spokespersons can have on health behaviors,” said A. Mark Fendrick, MD, study coauthor and co–editor in chief of The American Journal of Managed Care^®. “However, it is important to note that there is no guarantee that the endorsed services are backed by solid clinical evidence, as is the case of the use of ivermectin-benzimidazole for cancer treatment.”

References

1. Rockwell MS, Kahn KL, Fendrick AM, Vagala S, Mafi JN. Ivermectin-benzimidazole prescribing following celebrity endorsement. JAMA Netw Open. 2026;9(5):e2616780. doi:10.1001/jamanetworkopen.2026.16780
2. Smith R. Mel Gibson tells Joe Rogan ivermectin ‘cured’ stage four cancer. Newsweek. Updated January 13, 2025. Accessed May 13, 2026. https://www.newsweek.com/mel-gibson-joe-rogan-ivermectin-fenbendazole-cancer-podcast-2013180
3. Pradhan R. US Cancer Institute studying ivermectin’s ‘ability to kill cancer cells.’ KFF Health News. February 10, 2026. Accessed May 13, 2026. https://kffhealthnews.org/health-industry/ivermectin-cancer-treatment-nih-study-dewormer-offlabel-drug/ 
4. Cram P, Fendrick AM, Inadomi J, Cowen ME, Carpenter D, Vijan S. The impact of a celebrity promotional campaign on the use of colon cancer screening: the Katie Couric effect. Arch Intern Med. 2003;163(13):1601-1605. doi:10.1001/archinte.163.13.1601