How often can you use lice shampoo? - briefly
Lice treatment shampoo is applied once, with a second application 7–10 days later if live insects persist, and should not be used more than twice within a month.
How often can you use lice shampoo? - in detail
Lice treatment shampoo eliminates live insects and nits by delivering a neurotoxic agent to the parasite. The product is intended for a single, thorough application followed by a prescribed interval before a repeat dose.
The first application should be performed according to the label, typically after wetting the hair, applying the shampoo, and leaving it on for the specified time (usually 10 minutes). A second application is required after a period of 7–10 days, when any newly hatched lice emerge from surviving eggs. This interval aligns with the life cycle of head‑lice, which matures from egg to adult in approximately 7 days.
Age‑related guidelines
- Children older than 6 months: full‑strength dosage, repeat after 7–10 days.
- Children 2 months to 6 months: reduced concentration, repeat after 10 days if tolerated.
- Adults: full‑strength dosage, repeat after 7 days.
Safety considerations
- Do not exceed the recommended number of applications within a 30‑day period; most manufacturers limit use to two or three cycles.
- Avoid prolonged scalp contact; rinse thoroughly after the prescribed exposure time.
- Discontinue use if redness, itching, or burning intensifies; seek medical advice.
Resistant lice
- If nits persist after two cycles, consider a product containing a different active ingredient or combine with a nit‑combting regimen.
- In cases of confirmed resistance, a third application may be scheduled 14 days after the second treatment, but only under professional guidance.
A practical schedule:
- Day 0 – initial shampoo, follow label instructions.
- Day 7–10 – repeat shampoo, identical procedure.
- Day 14–21 – optional third application if live lice remain, otherwise discontinue.
Adhering to the outlined intervals maximizes efficacy while minimizing the risk of scalp irritation and chemical overexposure.