Both of these products use compounds derived from the extract of chrysanthemum flowers (pyrethrum or pyrethrins). These extracts have been used and studied for decades and the components have been refined or manufactured synthetically since World War II. These chemicals are called "synthetic pyrethroids" and generally end with the suffix "-thrin". Some have great pesticidal activity with quick knock-down (Bioallethrin) while others have long residual killer power (Permethrin). Generally, you cannot get both from one compound so producers often mix two different ones together in an oil-based solution.
However, there are some that can be mixed with water that provide sufficient knockdown in a few minutes but last for several weeks to months.
Insect Repellent for Clothing
