Guide

Thirty quiet minutes: how spinetoram works

The half hour after you apply Cheristin is quieter than you'd expect. The solution spreads across the skin's surface oils, and the active ingredient — spinetoram, at 11.2% — begins reaching the fleas moving through the coat. It works on contact: a flea doesn't have to bite your cat to receive its dose.

Spinetoram belongs to the spinosyn class of insecticides, developed from compounds first found in a soil bacterium. It overstimulates receptors in the flea's nervous system that mammals' nervous systems don't expose the same way — which is the short version of why a compound so quick against fleas is approved for a three-pound kitten.

The published numbers: fleas start dying within 30 minutes, and 98–100% of adult fleas are gone within 12 hours. In practice most owners describe the same scene — visible fleas slowing, then the cat sleeping harder that night than it has in weeks.

One dose keeps killing new fleas that jump aboard for six full weeks. That tail of protection is what breaks the flea life cycle in the house: adults die before they can lay the next generation of eggs into your carpet.

If the infestation is heavy, remember the drop only treats the animal. Eggs and larvae already in the bedding need laundry and a vacuum — our indoor-cat guide covers that half of the war.