Permethrin

Permethrin is a medication and chemical widely used as an insecticide, acaricide, and insect repellent. Permethrin is a first-line treatment for scabies. It is used as a cream.

It belongs to the family of synthetic chemicals called pyrethroids and functions as a neurotoxin, affecting neuron membranes by prolonging sodium channel activation. It is not known to rapidly harm most mammals or birds, but is toxic to fish and cats.

Permethrin is proven to be very ineffective against invisible biting mites. Some creams may have a beneficial effect for a period of time or may be useful against specific stages of mites. Permethrin and its man made substitutes are proven to be just as ineffective. If the chemical name ends in -thrin then it probably won't kill invisible biting mites.