An image shared on Facebook claims a “new” study found ivermectin causes sterility in 85 percent of men.

Verdict: False

Infertility in men is “not a known side effect” of ivermectin, according to a Food and Drug Administration (FDA) spokesperson. The study that is used to make the claim dates back to 2011, uses what can be considered a small sample size and lacks a control group.

Fact Check:

The image shows a screen grab of a tweet that reads, “A new study by researchers at three universities have concluded that ivermectin causes sterility in 85% of men.” It includes what looks like a link to a now-retracted WFLA.com article on the same topic.

Ivermectin is a medication approved by the FDA for human use to “treat infections caused by some parasitic worms and head lice and skin conditions like rosacea,” according to the FDA’s website. There is also a formulation of ivermectin for animals that has FDA approval to treat certain parasites. Some people have, according to The Washington Post, been taking either human or animal ivermectin in an attempt to treat COVID-19, despite the FDA not having authorized or approved it for the prevention or treatment of COVID-19 in humans or animals as of press time.

The referenced study was published in the Archives of Applied Science Research through the Scholars Research Library back in 2011. It screened 385 male patients in Nigeria who had been diagnosed with river blindness, only 37 of whom were “eligible for further tests, as their sperm counts were normal while the remaining patients had very low sperm counts and were therefore not used for further tests or were too weak after the preliminary screening tests and were not considered eligible for further test/studies,” according to the study.

The study says it measured various sperm functions of the 37 eligible patients before they received ivermectin and after 11 months of treatment with the medication to investigate the “effects of ivermectin therapy on the sperm functions.” Using only 37 patients can, according to a 2014 paper published in the Brazilian Annals of Dermatology, be considered too small of a sample size.

While the 2011 Nigerian study did state that “caution be seriously exercised in the treatment of male onchocerciasis patients with ivermectin to avoid the adverse effects it has on the patients’ sperm functions,” its own findings did not conclude ivermectin causes infertility in 85 percent of men. The study says it observed “significant reduction in sperm counts and sperm motility” of the patients, but could “not record any significant change or alteration in the sperm viscosity, sperm volume, and sperm liquefaction time.”

The 85-percent figure supposedly comes from a “recent report” that the study cites in its “References” section as being published in the Journal of Biomedical Investigation in 2002. Check Your Fact could not locate that report online. (RELATED: Will The FDA Not Authorize Or Approve Any COVID-19 Vaccine?)

Gideon Meyerowitz-Katz, an epidemiologist at Australia’s University of Wollongong, said on Twitter that the 2011 Nigerian study “doesn’t prove anything, certainly not that ivermectin causes sterility.”

Agree wholeheartedly. I’ve been a bit busy with all the rampant fraud, but I did quickly read that ivermectin/sperm count study and it doesn’t prove anything, certainly not that ivermectin causes sterility https://t.co/P4CgTnQ6zM

— Health Nerd (@GidMK) September 9, 2021

It was a small piece of research from nearly a decade ago that excluded 90% of the participants because they had sperm too poor to qualify for inspection. That alone means it’s impossible to draw any firm conclusions

— Health Nerd (@GidMK) September 9, 2021

There’s also no control group, so my guess would be that the authors were surveilling a very unwell population who happened to be taking ivermectin. Hard to tell if the medication contributed to that at all

— Health Nerd (@GidMK) September 9, 2021

“There’s also no control group, so my guess would be that the authors were surveilling a very unwell population who happened to be taking ivermectin,” he went on to say on Twitter. “Hard to tell if the medication contributed to that at all.”

The Archives of Applied Science Research, the journal that published the study in 2011, describes itself as being “peer-reviewed” but does not elaborate on its peer review process on the Scholars Research Library’s website. The journal also states it is financed by charging “handling fees received from authors and some academic/corporate sponsors.” Scholars Research Library appears on a list of “potential predatory scholarly open‑access publishers.”

A FDA spokesperson told Check Your Fact in an email that male infertility is “not a known side effect of ivermectin.” Common side effects of oral ivermectin can include headaches, muscle aches, nausea, dizziness, diarrhea and mild skin rash, according to a page on University of Michigan Health’s website.

“Infertility in men is not a known side effect of ivermectin and is not included as a side effect in the labeling,” the FDA spokesperson said. “The labeling for ivermectin and its bioequivalents states that ivermectin had no adverse effects on the fertility in rats in studies at repeated doses of up to 3 times the maximum recommended human dose of 200 mcg/kg (on a mg/m2/day basis). However, the FDA continues to monitor reports of all adverse events with ivermectin and will update the public as more information becomes available.”

“Though ivermectin is not a recommended treatment for COVID-19 and can cause toxicity there is no evidence that it has an impact on male fertility,” Dr. Amesh Adalja, a senior scholar at the Johns Hopkins Center for Health Security, told Check Your Fact in an email. (RELATED: Image Falsely Claims FEMA Is ‘Forcibly Vaccinating’ Hurricane Ida Evacuees)

The FDA currently states on its website that ivermectin “has not been shown to be safe or effective” for the treatment or prevention of COVID-19 in humans or animals. The agency has “received multiple reports of patients who have required medical attention, including hospitalization, after self-medicating with ivermectin intended for livestock,” its website states.

NBC affiliate station KTSM, which originally published the story about the 2011 Nigerian study, has since retracted it and published a statement, saying, “Concerns over the scientific research methods, the veracity of the original, peer-reviewed report and public statements by the Food and Drug Administration (FDA) saying that infertility is not a known side effect of Ivermectin all led to our editorial decision to remove the story.”

Scholars Research Library did not respond to a request for comment.