What ingredients are in lice shampoo? - briefly
Lice‑treatment shampoos usually combine an insecticidal agent such as permethrin, pyrethrin, or dimethicone with surfactants, conditioning agents, and sometimes a mild antiseptic or fragrance.
What ingredients are in lice shampoo? - in detail
A lice‑removing shampoo contains both active agents that kill the parasite and auxiliary substances that aid application and safety.
The primary insecticidal compounds are:
- Permethrin (1 % or 5 %) – a synthetic pyrethroid that disrupts the nervous system of lice, leading to paralysis and death.
- Pyrethrins (0.5 %–1 %) – natural extracts from Chrysanthemum flowers; act similarly to permethrin but are less stable, requiring additional stabilizers.
- Dimethicone (10 %–30 %) – a silicone oil that coats lice, suffocating them without neurotoxic effects; also reduces irritation on the scalp.
- Malathion (0.5 %–1 %) – an organophosphate that inhibits acetylcholinesterase, causing overstimulation of the nervous system; used in prescription‑strength formulations.
- Spinosad (0.5 %–1 %) – a bacterial‑derived compound that interferes with nicotinic acetylcholine receptors; effective against resistant strains.
- Benzyl alcohol (5 %–10 %) – a non‑neurotoxic agent that penetrates the exoskeleton and kills lice through desiccation.
- Ivermectin (0.5 %–1 %) – a macrocyclic lactone that blocks glutamate‑gated chloride channels, leading to paralysis.
Supporting ingredients include:
- Surfactants (e.g., sodium laureth sulfate, cocamidopropyl betaine) – lower surface tension, allowing the active agent to spread evenly across hair shafts.
- Conditioning agents (e.g., panthenol, glycerin) – mitigate dryness and maintain hair elasticity after treatment.
- Preservatives (e.g., phenoxyethanol, methylparaben) – prevent microbial growth in the product container.
- pH adjusters (e.g., citric acid, sodium hydroxide) – keep the formulation within a scalp‑compatible range (pH 5–6).
- Fragrance and coloring agents – improve user experience but are present in minimal concentrations to avoid sensitization.
Each component serves a specific role: the insecticidal agents eradicate the parasites, while surfactants ensure thorough coverage, conditioners protect the hair, and preservatives maintain product stability. The combined formulation delivers a rapid, effective, and safe solution for eliminating head lice.