How does a lice spray work? - briefly
The spray applies an insecticidal compound—often a neurotoxic agent like pyrethrin—that penetrates the lice’s exoskeleton and disrupts nerve function, leading to rapid paralysis and death. A residual layer on hair and scalp maintains effectiveness for several days.
How does a lice spray work? - in detail
Lice spray is a topical insecticide formulated to eradicate head‑lice infestations. The product combines an active neurotoxic agent with carriers that ensure uniform distribution over hair and scalp.
The active ingredient typically belongs to the pyrethroid class, such as permethrin or pyrethrin. These compounds bind to voltage‑gated sodium channels in the lice nervous system, prolonging channel opening and causing uncontrolled neuronal firing. The resulting hyperexcitation leads to rapid paralysis and death of the parasite.
The formulation includes a volatile propellant, a solvent that dissolves the active compound, and surfactants that reduce surface tension. When the aerosol is discharged, fine droplets penetrate the hair shaft and coat the exoskeleton of lice and their nits. The solvent facilitates absorption of the neurotoxin through the cuticle, while surfactants improve spread across the scalp.
Application proceeds as follows:
- Dispense spray onto dry hair, ensuring complete coverage from scalp to hair tips.
- Massage gently to distribute droplets evenly over all strands.
- Maintain contact for the manufacturer‑specified duration, typically 10 – 15 minutes, to allow sufficient absorption.
- Remove excess product with a towel or by rinsing, depending on product instructions.
After treatment, dead lice are visible on the hair and scalp, and subsequent combing removes residual bodies and nits. Re‑treatment may be recommended after 7–10 days to address any newly hatched nymphs that survived the initial exposure.