What does ivermectin actually treat, and how strong is the evidence for uses beyond parasitic infections?

Ivermectin is an important human medicine. Oral formulations are FDA-approved for intestinal strongyloidiasis and onchocerciasis, while certain topical formulations treat head lice or rosacea. The disease and formulation matter; the credibility of these uses does not prove every proposed use of the same molecule. Laboratory findings can identify possible antiviral or anticancer mechanisms, but they cannot establish that effective concentrations are achievable safely in a person, or that treatment improves survival, symptoms or quality of life.[1]

COVID-19 provides a useful example of the distinction. In ACTIV-6, ivermectin did not meaningfully shorten recovery in outpatients with mild-to-moderate infection; another randomized trial, COVID-OUT, also did not establish benefit on its primary serious-illness outcome. FDA has not approved it for COVID-19. For other repurposing claims, including cancer, a convincing answer requires controlled human outcomes for the specific disease rather than extrapolation from cell studies or testimonials. Veterinary preparations should not be substituted for human medicines, and an experimental claim should not displace treatment already shown to help.[1][2][3]