I would hazard a guess they are using a water soluble formulation of ivermectin with a <i>very</i> short half life in the body (I didn't know such a thing existed) - since the usual fat hungry types applied subcutaneously or to the skin layer via a suitable solvent / binder like glycerine at 1200 micrograms per kilo is enough to cause significant blood brain barrier issues in animals like dogs. Humans can be slightly more resilient to some chemicals, but given the percentage of poor reaction to a 200 micrograms per kilo dose is similar or comparable between humans and dogs (bar a couple of breeds which are finicky with a small percentage which the dose results in a fatally,) it'd be a brave researcher exposing a test subject (person) to much more than ten times the standard dosage of fat hungry ivermectin formulation.<p>It's also used to help control malaria, but iirc, it's not antimalarial at standard dose rates.