If lice are not completely covered by oil, they may not die but the oil will slow them down allowing them to be caught in the nit comb.
Even though it is very likely that a single application of the oil will kill all stages (eggs, nymphs and adults) of the lice, I recommend retreatment about 7 days after the initial treatment.
Blow dry your child's hair. It has to be thoroughly dry down to the scalp to suffocate the lice. Expect this to take 3 times longer than normal drying. The dried Cetaphil will smother the lice.
But here's the problem: Lice can actually cut off those spiracles and hold their breath for up to eight hours! Because these oils are relatively thin, the bugs are easily able to shut those breathing tubes before the oil has a chance to seep into them to block them.
Head lice survive less than one or two days if they fall off the scalp and cannot feed. Head lice eggs (nits) cannot hatch and usually die within a week if they do not remain under ideal conditions of heat and humidity similar to those found close to the human scalp.
The only way to prevent them from hatching would be to remove them with a good metal nit comb, or your fingernails. Nits are laid by the mother and attached with a glue she formulates, to sit on the hair shaft in the perfect spot to incubate and hatch.
Nits are often confused with other things found in the hair such as dandruff, hair spray droplets, and dirt particles. If no live nymphs or adult lice are seen, and the only nits found are more than ¼-inch from the scalp, the infestation is probably old and no longer active and does not need to be treated.
Anise oil
Anise oil may coat and suffocate lice . A 2018 study of natural remedies for lice in children found that anise oil was one of the most effective natural remedies.
Olive Oil smothers and kills active head lice, making nit removal easier and moisturizing the hair and scalp. Part hair and apply the oil directly onto the scalp. Massage into the entire scalp making sure to saturate the hair. Apply a shower cap.
Use heat. Wash any items used or worn by the person in hot water, and dry them on high heat. Lice and nits die when exposed to temperatures higher than 130 F for more than 5 minutes. Wash anything that touched the person's skin or scalp, including jackets, hats, scarves, pillowcases, sheets, and headbands.
Wash any lice-infested item in hot water that is at least 130°F (54°C), put it in a hot dryer for 15 minutes or more, or placing the item in an air-tight plastic bag and leaving it for two weeks to kill the lice and any nits. You can also vacuum floors and furniture where lice may have fallen.
Malathion is pediculicidal (kills live lice) and partially ovicidal (kills some lice eggs). A second treatment is recommended if live lice still are present 7–9 days after treatment.
In addition to removing the live bugs from the hair with the comb, you can use olive oil to kill lice by saturating the hair in it and leaving it on for 8 hours (lice can hold their breath for that long) so that the oil will suffocate the bugs.
Soak your child's head in olive oil or coconut oil. Cover with a shower cap for at least 2 hours (or preferably overnight). When ready, remove the shower cap, and separate the hair into small sections, then use a metal nit comb to carefully remove the lice and eggs.
Aniseed, cinnamon leaf, and tea tree oil have shown promising results. Mixing a few drops of any of these essential oils in coconut oil could help kill the lice and neutralize their eggs.
Technically the answer to that is yes. Practically speaking if the lice are on your head, you would need to apply an oil, like olive oil, to the hair and leave it on for at least 8 hours. You obviously cannot submerge the head in water for 8 plus hours in order to drown them or you will drown, as well!
What repels head lice? Coconut, tea tree oil, lavender, eucalyptus, rosemary, lemon grass, and peppermint are scents popularly believed to repel lice. Using any coconut scented shampoo and conditioner is an easy way to increase your defense. At 1% concentration, tea tree oil killed 100% of head lice after 30 minutes.
The conditioner does not kill lice but stuns them for about 20 minutes enabling easier removal. The long toothed metal comb will remove nits and the stunned head lice. Wipe the comb on a white tissue and check for any lice or nits. Keep combing until no more appear on the tissue.
Blow dry their hair completely. This will take a long time but it helps “seal in” and suffocate the live lice. Put a shower cap, head wrap or skull cap on and leave the dried lotion on for at least 8 hours. It's easiest to do this overnight.
If nits are yellow, tan, or brown, it means the lice haven't hatched yet. If the nits are white or clear, the lice have hatched and just the egg remains. Lice eggs hatch within 1 to 2 weeks after they're laid.
If you do not comb out all the remaining nits, they will hatch and restart the cycle in 7-10 days from that point. That's why we recommend 3 treatments over a 12-day period of time. This stops the life cycle of lice. These are nits at different stages and a louse.
Generally, if no live crawling insects are seen three weeks after the treatment, it's safe to assume that they are gone. Nits would have hatched by that time if they were alive. Nits and their shells may remain in the hair for some time but won't be viable.
Adults are not immune to head lice. In fact, if you have any close contact with children or even parents of children you can be at risk of catching them if they have them. Lice transfer primarily through head to head contact, so you would have to get close to the other person.
Rinse the comb in a sink or bowl of warm water, and wipe dry. Continue section by section until the entire head is done. Make sure hair stays wet with conditioner during combing. Metal or plastic nit combs are available at your local pharmacy.