Getting rid of head lice takes a combination of killing the live lice, removing their eggs, and repeating the process about a week later to catch any newly hatched survivors. Most cases can be handled at home with over-the-counter treatments and thorough combing, though some stubborn infestations need prescription options. The key is understanding the lice lifecycle so you can time your treatment correctly.
Why Timing Matters
Lice eggs (called nits) take about 8 to 9 days to hatch after they’re laid near the base of the hair shaft. Once hatched, a young louse matures into an egg-laying adult in 7 to 12 days. Adults can live up to 30 days on your head. This lifecycle is the reason a single treatment rarely works: most products kill live lice but not all the eggs. You need a second treatment 7 to 9 days later to kill the nymphs that hatched after your first round, before they’re old enough to start laying eggs themselves.
Over-the-Counter Treatments
The most widely available option is a permethrin-based cream rinse, sold under brand names like Nix. You apply it to clean, towel-dried hair, leave it on for 10 minutes, then rinse. Because permethrin doesn’t reliably kill eggs, plan on a second application about 9 days later. One important caveat: lice in many areas have developed resistance to permethrin, which means it may not work as well as it once did. If you’ve followed the directions carefully and still see live lice a day or two after treatment, resistance is the likely culprit, and it’s time to try a different approach.
Prescription Options
If over-the-counter products fail, several prescription treatments target lice through different mechanisms, which matters when resistance is the issue.
- Ivermectin lotion (0.5%): Approved for ages 6 months and older. It kills live lice and, while it doesn’t kill eggs directly, it prevents newly hatched nymphs from surviving. This often eliminates the need for a second treatment.
- Spinosad suspension (0.9%): Also approved for ages 6 months and older. Derived from soil bacteria, it kills both live lice and unhatched eggs, so retreatment is usually unnecessary.
- Malathion lotion (0.5%): Approved for ages 6 and older. It kills live lice and some eggs, but a second treatment may still be needed if you find surviving nits after 7 to 9 days.
Wet Combing: The Chemical-Free Method
Wet combing is a proven technique that works without any chemicals. It’s also a valuable supplement to any medicated treatment, since physically removing nits improves your odds of clearing the infestation in one cycle. Here’s the step-by-step process:
- Wash the hair with ordinary shampoo.
- Apply a generous amount of conditioner to make the hair slippery and easier to comb through.
- Use a wide-toothed comb first to detangle the hair completely.
- Switch to a fine-toothed lice comb (metal combs with closely spaced teeth work best).
- Slot the teeth of the comb into the hair at the roots, with the edge lightly touching the scalp, and draw it all the way down to the ends.
- After each stroke, check the comb and wipe or rinse off any lice or nits you find.
- Work through the entire head section by section so you don’t miss any areas.
If you’re using wet combing as your sole treatment, repeat the process every 3 to 4 days for at least two weeks. The conditioner immobilizes live lice, making them easier to catch, and repeated sessions ensure you remove nymphs before they mature. When combined with a medicated treatment, combing right after the product is applied helps clear the dead lice and leftover nits that might otherwise be mistaken for an active infestation.
Cleaning Your Home
The good news about household cleaning is that lice are far less hardy away from a human head than most people think. Adult lice die within two days if they fall off a person and can’t feed. Nits that aren’t kept at scalp temperature usually die within a week and can’t hatch. So you don’t need to deep-clean your entire house or bag up belongings for weeks.
Focus your effort on items that touched the head of the infested person in the two days before treatment:
- Machine wash pillowcases, sheets, towels, and recently worn hats or scarves in hot water, then dry on the hot cycle for at least 20 minutes. Temperatures above 125°F for 10 minutes kill both lice and nits.
- Items that can’t be washed (stuffed animals, decorative pillows) can go in the dryer on high heat for 20 minutes, or be sealed in a plastic bag for two weeks as an extra precaution.
- Vacuum upholstered furniture, car seats, and carpeted areas where the person sat or lay down.
- Soak combs and brushes in hot water (at least 130°F) for 5 to 10 minutes.
You do not need to spray furniture or rooms with insecticide. Lice can’t jump or fly, and they spread almost exclusively through direct head-to-head contact. Spending hours sanitizing your home has far less impact than properly treating the hair.
What About Natural Remedies?
Tea tree oil is the most commonly discussed natural alternative. Small preliminary studies have shown some reduction in infestation levels when tea tree oil shampoo and conditioner were used consistently, but the evidence is far weaker than what exists for medicated treatments. One small trial of 26 schoolchildren found infestation levels dropped over four weeks of twice-weekly tea tree oil shampoo use, but there was no comparison group receiving no treatment, making it hard to draw firm conclusions.
Home remedies like mayonnaise, olive oil, or petroleum jelly are sometimes suggested as “suffocation” methods. While coating the hair in a thick substance can immobilize some lice, these approaches haven’t been shown to reliably kill lice or their eggs. If you prefer to avoid chemicals entirely, wet combing with conditioner is a better-studied alternative.
Special Considerations for Young Children and Pregnancy
Most prescription lice treatments are approved for children 6 months and older. For infants younger than that, manual removal through wet combing is the safest approach. During pregnancy, most topical lice treatments are considered low-risk since they’re applied to the skin rather than taken internally, but lindane should be avoided because it can cause toxic side effects if misused. Lindane is also not recommended for use during breastfeeding or on young children.
How to Tell the Infestation Is Gone
After treatment, finding nits glued to the hair doesn’t necessarily mean you still have an active infestation. Dead nits and empty egg casings can remain attached to the hair shaft for weeks or months as the hair grows out. What matters is whether you’re finding live, moving lice or new nits laid close to the scalp (within a quarter inch of the skin). If you see no live lice after two thorough combing sessions spaced a week apart, you’re likely in the clear. Itching can persist for a few days after successful treatment because it’s a reaction to louse saliva, not a sign of ongoing infestation.