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How long does it take for Sklice (ivermectin) to kill head lice?

Medically reviewed by Sally Chao, MD. Last updated on Dec 24, 2021.

Official answer


Sklice (ivermectin 0.5% topical lotion) kills most head lice infestations with one 10-minute application on dry hair and scalp. In studies, 71 to 76% of patients were completely lice-free 2 weeks after one Sklice treatment.

Sklice is now available over the counter as a single use treatment. It’s approved to treat head lice in patients 6 months of age and older.

It is well tolerated, but side effects of Sklice may include:

An adult should supervise the Sklice application in children. Take care not to get Sklice in the eyes.

When using Sklice lotion, you should also perform other self-care tasks to eliminate lice. These include:

  • Wash your hands after using Sklice.
  • Use hot water to wash or dry-clean all items that were recently worn, such as hats, clothes, bedding and towels.
  • Wash brushes, combs and hair clips in hot water.
  • Nit combing is not needed when using Sklice, but a comb may be used to remove dead lice and nits.

According to the Centers for Disease Control and Prevention, ivermectin oral tablets are not Food and Drug Administration (FDA)-approved to treat head lice, but a single dose of 200 micrograms/kg or 400 micrograms/kg repeated 9 to 10 days later has also been shown to be successful in killing head lice. Ivermectin tablets are not approved for use in children who weigh less than 15 kg or in women who are pregnant.

  1. U.S. Food and Drug Administration (FDA). SKLICE (ivermectin) Lotion, 0.5%, for topical use. June 2017. Available at: [Accessed December 15, 2021].
  2. Sanofi. Sklice® (ivermectin) Lotion, 0.5% Now Available in the US for Topical Treatment of Head Lice. August 20, 2012. Available at: [Accessed December 10, 2021].
  3. U.S. Food and Drug Administration (FDA). FDA Approves Lotion for Nonprescription Use to Treat Head Lice. October 27, 2020. Available at: [Accessed December 10, 2021].
  4. Centers for Disease Control and Prevention (CDC). Parasite Treatment. October 15, 2019. Available at: [Accessed December 11, 2021].

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