You can treat most cases of head lice at home using a combination of a pediculicide (lice-killing product) and thorough combing with a fine-toothed nit comb. The key to success is following the full treatment timeline, including a second application 7 to 10 days after the first, because no single treatment reliably kills both live lice and unhatched eggs in one go.
Why Most OTC Products Need Two Rounds
Head lice eggs take about 8 to 9 days to hatch. The most common over-the-counter treatments, permethrin lotion (sold as Nix) and pyrethrin-based shampoos (sold as Rid, among others), kill live lice but not unhatched eggs. That means a single application leaves eggs behind. If you don’t treat again around day 9 or 10, newly hatched lice can mature and start laying eggs of their own, restarting the cycle.
Permethrin does have some residual activity, meaning it can kill newly hatched lice for a few days after application. Pyrethrins do not. Either way, a second treatment is the standard recommendation.
The Resistance Problem
There’s a catch with these classic treatments. Lice in the United States have developed widespread genetic resistance to permethrin and pyrethrins. A large sampling study published in the Journal of Medical Entomology found that lice from 42 of 48 states tested (88%) carried full resistance mutations. The overall resistance rate across all samples was 98.3%. The American Academy of Pediatrics has noted that clinical effectiveness of pyrethrins has dropped from near 100% when they were introduced in the 1980s to as low as 25% in some studies.
This doesn’t mean these products never work. Some families still have success with them, and they remain the cheapest first option. But if you apply permethrin or pyrethrins correctly, complete the second treatment, and still see live lice crawling a day or two after treatment, resistance is the likely explanation. At that point, you need a different approach.
Step-by-Step OTC Treatment
If you’re starting with permethrin or pyrethrins, follow the product directions closely. Apply to dry or towel-dried hair (check the label), leave on for the specified time, and rinse. Do not use conditioner before applying, as it can reduce the product’s effectiveness. Then comb through the hair with a fine-toothed nit comb to remove dead lice and as many eggs as possible.
Repeat the full treatment on day 9 or 10. Between treatments, check the scalp every 2 to 3 days. If you see live, crawling lice within a day of the first treatment, the product likely isn’t working.
A newer OTC option is ivermectin 0.5% lotion (sold as Sklice). It works differently from permethrin and is effective against resistant lice. In two U.S. clinical trials, a single application cured 71% to 76% of infestations at 14 days. It costs more than permethrin, but it’s worth considering if you live in an area with known resistance or if a permethrin product has already failed.
The Wet Combing Method
Wet combing is a chemical-free alternative that works purely through physical removal. It requires patience and consistency but avoids any resistance issues entirely. In one study, 15 out of 22 children treated with wet combing alone were cured, a rate comparable to chemical treatment in the same study.
Here’s how to do it:
- Day 1: Apply a generous amount of regular hair conditioner to wet hair. The conditioner immobilizes lice temporarily and helps the comb glide through. Using a fine-toothed metal nit comb, work through the entire head in systematic sections from scalp to tip. Wipe the comb on a white paper towel after each stroke so you can see what you’re removing.
- Day 4 or 5: Repeat the full wet combing session.
- Day 9 or 10: Repeat again. This session catches any lice that hatched from eggs you missed.
- Day 14: Final combing session and check. If you find no live lice, the infestation is cleared.
The schedule matters because it’s designed around the lice life cycle. Eggs hatch around day 8 or 9, and newly hatched lice can’t lay their own eggs for about another 9 to 10 days. By combing every 4 to 5 days over two weeks, you catch each generation before it can reproduce. Skipping sessions or spacing them too far apart is the most common reason this method fails.
The Suffocation Approach
Some families use a thick skin cleanser (Cetaphil Gentle Skin Cleanser is the most commonly referenced) as a suffocation agent. The idea is that the product coats the lice and, once dried, blocks their breathing holes. Apply the cleanser to completely dry hair from scalp to tips, wait two minutes, then comb out the excess along with any visible nits. Blow dry the hair thoroughly and leave the dried film on the scalp for at least 8 hours (overnight works well), then wash it out. This is typically repeated weekly for three weeks.
This method has less rigorous clinical evidence behind it than permethrin or wet combing, but some pediatricians recommend it as a nontoxic alternative, particularly for young children or families dealing with resistant lice.
Tea Tree Oil and Other Home Remedies
Tea tree oil does have real insecticidal activity against lice. Lab research found that a 1% concentration of tea tree oil killed 100% of live lice within 30 minutes. Its ability to kill eggs is weaker, though. It took a 2% concentration to cause 50% of eggs to fail to hatch, and even then results took four days to appear.
The problem is translating lab results to real-world use. There are no standardized protocols for concentration, application time, or how to combine tea tree oil with a carrier product for safe scalp use. Undiluted essential oils can irritate or burn skin. Other plant-based oils like eucalyptus, lavender, and lemon tea tree oil have shown some activity in lab studies as well, but none have been tested thoroughly enough to give you a reliable treatment plan.
If you want to try tea tree oil, treat it as a supplement to a proven method (wet combing or an OTC product) rather than a standalone cure.
Cleaning Your Home
Lice can only survive about 1 to 2 days off the human scalp, so you don’t need to deep-clean your entire house. Focus on items the infested person’s head has touched in the two days before treatment:
- Bedding, pillowcases, and recently worn clothes: Machine wash in hot water (at least 130°F) and dry on high heat.
- Items that can’t be washed: Seal them in a plastic bag for two weeks. Any lice or eggs will die without a host in that time.
- Combs and brushes: Soak in hot water (at least 130°F) for 5 to 10 minutes.
- Furniture and carpets: A quick vacuum of areas where the person’s head rested is sufficient. You do not need to spray insecticides on furniture or in rooms.
How to Tell if Treatment Worked
The only reliable sign of an active infestation is live, crawling lice. Nits (eggs) glued to hair shafts can stick around for weeks after successful treatment and don’t necessarily mean the infestation is ongoing. Live eggs are usually brown and found close to the scalp, within a quarter inch. White or clear shells farther down the hair shaft are almost always already hatched or dead.
Check the scalp 2 to 3 days after each treatment. If you see no live lice by day 14 after starting treatment, you’re in the clear. If live lice keep appearing despite completing the full treatment cycle, the product you used likely isn’t effective, and it’s time to try a different method or talk to your child’s doctor about a prescription option like spinosad or higher-strength ivermectin.