Ivermectin: The Dewormer For All That Ails You

Candidates for ivermectin treatment.

Since the COVID pandemic there has been a constant murmuring about the use of ivermectin to treat a range of ailments from COVID-19 to cancer. Since all of these uses are off-label, it is worth taking a minute to dig deeper into the evidence.

What Is Ivermectin?

Ivermectin is a broad-spectrum anti-parasitic, and in this context is regarded as something of a wonder drug. It is used to treat a range of parasitic infections in horses, including strongyles, lungworms, pinworms, ascarids, hairworms, large-mouth stomach worms, neck and intestinal threadworms, and stomach bots. It is also used in other livestock, as well as in dogs for prevention of heartworm.

For humans, ivermectin is FDA approved for treatment of intestinal strongyloidiasis caused by a type of threadworm, and for treatment of onchocerciasis, aka river blindness. Topical forms are also used to treat head lice, scabies and rosacea. Only rosacea is not a parasitic infection (but inflamed skin may be more susceptible to these infections).

COVID-19

Preclinical research has indicated that ivermectin may have antiviral properties, so has been proposed as a treatment for COVID-19 infection. This is supported by in vitro experiments, but the concentrations required far exceed what would be safe in humans.

A PubMed search for clinical trials of ivermectin in COVID-19 yields 43 studies (two of these were later retracted). The vast majority of these found that it was ineffective. One study did find that ivermectin did reduce SARS-CoV-2 viral load in patients with mild to moderate COVID-19, but did not have any significant effect on clinical symptoms (Wijewickrema, 2024). Another study in asymptomatic patients also found that ivermectin was associated with a reduction in viral load (Mouawia, 2026). While both of these studies showed that ivermectin reduced viral load, in neither case did it have an effect on the clinical course of disease, suggesting that the drug has no clinical utility. A third similar study, however, suggested that reduced viral load may help to reduce transmission (Biber, 2022), but this has not been proven. Only two studies reported a reduction in the duration of symptoms, including fever, cough, dyspnea, lymphopenia, and anosmia, with an intranasal formulation of ivermectin compared to placebo (Aref, 2021; Shahbaznejad, 2021).

Cancer

A recent study found that prescriptions for ivermectin had increased 2.5-fold after Mel Gibson said that it was effective for treatment of cancer on the Joe Rogan show (Rockwell, 2026). However, there are precisely zero clinical trials (positive or negative) investigating the utility of ivermectin in treatment of cancer.

Lupus

Although there have been a number of case reports of ivermectin in treatment of lupus, a closer inspection shows that most of these are description of on-label (mainly topical) treatment of parasitic infections, such as Strongyloides stercoralis infection. There is no evidence that ivermectin can treat lupus itself, and no clinical trials have been published.

Conclusions

There is essentially no evidence that ivermectin is effective for treatment of COVID-19, cancer, lupus or any condition beyond parasitic infections. Despite this, misinformation spread by celebrities has led many people to eschew cancer treatment in favour of ivermectin ([Rockwell, 2026](http://Conclusions There is essentially no evidence that ivermectin is effective for treatment of COVID-19, cancer, lupus or any condition beyond parasitic infections. Despite this, misinformation spread by celebrities has led many people to eschew cancer treatment in favour of ivermectin (Rockwell, 2026). Others have died from ingesting unsafe quantities of the drug formulation intended for horses. https://www.cbsnews.com/colorado/news/ivermectin-death-warnings-misuse-drug-colorado/ Don’t be a horse’s arse, follow the science.)). Others have died from ingesting unsafe quantities of the drug formulation intended for horses. Don’t be a horse’s arse, follow the science.

References:

Wijewickrema A, Banneheke H, Pathmeswaran A, et al. BMC Infect Dis. 2024;24:719.

Mouawia H, Saab HB, Ayoub H, et al. TriLA. 2026;27:447.

Biber A, Harmelin G, Lev D, et al. Int J Infect Dis. 2022;122:733–740.

Aref ZF, Bazeed SEES, Hassan MH, et al. Int J Nanomedicine. 2021;16:4063–4072.

Shahbaznejad L, Davoudi A, Eslami G, et al. Clin Ther. 2021;43:1007–1019.

Rockwell MS, Kahn KL, Fendrick M, et al. JAMA Network Open. 2026;9:e2616780.