Head lice are treatable at home in most cases using over-the-counter products, prescription options, or physical removal with a fine-toothed comb. The key to success is choosing an effective product, applying it correctly, and following up to catch any lice that hatch after the first treatment. Most infestations clear within two to three weeks.
Start With an OTC Treatment
Permethrin 1% lotion is the most widely recommended first option. It’s available without a prescription, safe for children 2 months and older, and applied to clean, towel-dried hair. You leave it on for 10 minutes, then rinse. Permethrin kills live lice but not all eggs, so a second application is needed about 9 days later to kill any newly hatched lice before they can lay more eggs.
There’s an important caveat: permethrin resistance is now widespread. Genetic studies have found that the mutations responsible for resistance are present in lice populations across the United States, the United Kingdom, Denmark, and Japan. In some tested populations, nearly all lice survived a full dose. If you use permethrin and still see live lice crawling two to three days after treatment, it’s likely not working, and you should switch to a different approach.
Prescription Treatments for Resistant Lice
If over-the-counter products fail, several prescription options work through different mechanisms that resistant lice can’t dodge.
- Ivermectin 0.5% lotion: Kills live lice and also prevents newly hatched nymphs from surviving, which means a single application is often enough. Approved for children 6 months and older.
- Spinosad 0.9% suspension: Derived from soil bacteria, this kills both live lice and unhatched eggs. Retreatment is usually unnecessary, making it one of the most convenient options.
- Malathion 0.5% lotion: Kills live lice and some eggs. Approved for children 6 and older. It’s flammable, so you need to keep hair away from heat sources while it’s on.
- Benzyl alcohol 5% lotion: Works by suffocating lice rather than acting as a traditional insecticide. It does not kill eggs, so retreatment at 7 to 9 days is necessary.
Wet Combing as a Standalone Method
If you prefer to avoid chemicals entirely, or you’re treating a very young infant, physical removal with a fine-toothed nit comb is a legitimate option. It requires patience and consistency but works well when done correctly.
Saturate the hair with conditioner to slow the lice down and make them easier to comb out. Divide the hair into small sections and comb from the scalp to the tips, wiping the comb on a white paper towel after each pass so you can see what you’re removing. Repeat this every two to three days for at least two to three weeks. The extended timeline matters because you need to keep catching newly hatched lice before they mature enough to lay eggs. Flea combs designed for cats and dogs also work, since the teeth are spaced tightly enough to trap lice and their eggs.
Wet combing can also be combined with a medicated treatment for the best results. Use the product to kill live lice, then comb out the dead lice and remaining eggs in the days that follow.
Essential Oils and Home Remedies
Tea tree oil and other plant-based remedies are popular, but the evidence is mixed. One clinical comparison found that a product containing tea tree oil and lavender oil cleared lice in 97.6% of subjects, compared to only 25% for a traditional pyrethrin-based product. That’s a striking result, but it came from a single formulated product, not from dabbing pure essential oil onto the scalp. Eucalyptus oil showed around 82.5% effectiveness in another comparison.
On the other hand, neem extract performed worse than permethrin and malathion in lab tests, and pure tea tree oil was less effective than other chemical insecticides in head-to-head comparisons. The takeaway: some plant-based formulations can work, but “natural” doesn’t automatically mean effective. If you go this route, use a commercially prepared product rather than mixing your own, and still follow up with consistent combing.
Home remedies like coating the hair in mayonnaise, olive oil, or petroleum jelly aim to suffocate lice. There’s limited clinical data on these, and they need to stay on for hours (often overnight under a shower cap) to have any chance of working. They won’t kill eggs, so you’d still need repeated applications and diligent combing.
Why Treatments Fail
The most common reason treatment doesn’t work is resistance to the product you’re using. But several other factors trip people up:
- Skipping the second treatment. Most products don’t kill all the eggs. If you skip the follow-up application at 7 to 9 days, newly hatched lice survive and restart the cycle.
- Not combing out eggs. Even after a successful treatment, viable eggs (nits) glued to the hair shaft can hatch. Combing every two to three days for two to three weeks catches what the product missed.
- Applying product to wet or heavily conditioned hair. Some treatments need to be applied to dry or only slightly damp hair. Excess water or conditioner can dilute the product and reduce its effectiveness.
- Reinfestation from close contacts. If a sibling, classmate, or household member still has lice, head-to-head contact will bring them right back. Check everyone in the household and treat anyone who has live lice.
- Misidentification. Dandruff, hair casts, and dried hair product can all look like nits. If you’re treating repeatedly and never finding live crawling lice, you may not actually have an active infestation.
Cleaning Your Home
Lice can survive off the human scalp for roughly a week at room temperature, though they weaken quickly without a blood meal. You don’t need to fumigate your house, but a few targeted steps help prevent reinfestation.
Wash pillowcases, sheets, hats, and any recently worn clothing in hot water and dry on high heat. Items that can’t be washed can be sealed in a plastic bag for two weeks, which is long enough for any lice or eggs to die. Soak combs and brushes in hot water (at least 130°F) for 5 to 10 minutes. Vacuum upholstered furniture and car seats where the infested person’s head may have rested.
Skip the lice sprays for furniture and carpets. Lice don’t live in your environment the way fleas do. They need human blood to survive and spend almost their entire lives on the scalp. Your energy is better spent on thorough treatment and combing than on deep-cleaning every surface in the house.
A Practical Treatment Timeline
Here’s what a typical successful treatment looks like from start to finish:
Day 1: Apply your chosen treatment. Comb out dead lice and as many nits as possible afterward.
Days 3, 5, and 7: Wet comb with conditioner, checking for any live lice. If you see live, crawling lice on day 3, your product may not be working, and you should consider switching.
Day 9: Apply the second treatment (unless you used a product like spinosad that doesn’t require retreatment). Comb again afterward.
Days 11 through 21: Continue checking every two to three days. If you go two full weeks with no live lice spotted during combing, the infestation is cleared.