Getting rid of lice requires killing both the live insects and dealing with their eggs (nits), which hatch over the course of about a week. A single treatment is rarely enough. The most reliable approach combines a topical treatment with thorough combing and a well-timed second application to catch newly hatched lice before they can lay more eggs.
Check That It’s Actually Lice
Before you start treatment, make sure you’re dealing with lice and not dandruff, dry scalp flakes, or hair product residue. Nits are tiny, oval-shaped structures glued firmly to individual hair strands, usually within a quarter inch of the scalp. Unlike dandruff, they don’t brush off easily. If you slide a suspected nit between your fingernails and it resists, that’s a strong sign it’s real. Viable nits look brownish and opaque, while empty, already-hatched shells appear translucent and white.
Loose flakes, sometimes called pseudo-nits, tend to be irregularly shaped and slide freely along the hair shaft. If you’re unsure, a fine-toothed lice comb run through wet, conditioned hair will catch live lice and make diagnosis obvious.
Why Treatment Timing Matters
Lice eggs hatch in 6 to 9 days. The newly hatched nymphs then take about 7 more days to mature into adults capable of reproducing. Adults can survive up to 30 days on a human head. This life cycle is why you need a second treatment roughly 7 to 9 days after the first: the goal is to kill any nymphs that hatched from eggs that survived the initial round, before those nymphs grow up and start laying eggs of their own.
Over-the-Counter Treatments
The two main active ingredients in drugstore lice products are pyrethrins (often combined with piperonyl butoxide) and 1% permethrin lotion. Both work by attacking the nervous system of the louse. You apply the product to dry or towel-dried hair (depending on the label), leave it on for the specified time, then rinse. A second application is typically needed 7 to 9 days later.
Here’s the catch: lice have developed significant resistance to these ingredients worldwide. Studies of lice populations have found resistance-related genetic mutations at rates of 74% in the United States, over 75% across the European Union, and close to 100% in some regions of Oceania. In practical terms, this means over-the-counter products may simply not work for many families. If you’ve completed a full course of treatment (two applications, properly timed) and still find live lice, resistance is the likely reason, and it’s time to try a different approach.
Prescription Options
When drugstore treatments fail, a healthcare provider can prescribe stronger options that work through different mechanisms, making them effective even against resistant lice. These include topical lotions that suffocate lice or disrupt their biology in ways that pyrethroid-based products don’t. Some prescription treatments have the added advantage of killing both live lice and eggs in a single application, eliminating the need for precise retreatment timing. Your provider will choose based on your child’s age and the specifics of the infestation.
Wet Combing as a Standalone Method
If you want to avoid chemicals entirely, or if you’re dealing with an infant too young for medicated products, wet combing is a proven alternative. It has strong clinical trial evidence supporting its effectiveness, and it carries zero risk of side effects. The tradeoff is time and persistence.
Here’s the process:
- Wash hair with ordinary shampoo, then apply a generous amount of conditioner. The conditioner slows the lice down and makes the comb glide smoothly.
- Detangle first with a wide-toothed comb, then switch to a fine-toothed lice comb with tooth spacing under 0.3 mm. The teeth should be just slightly wider than the hair.
- Work section by section from the roots to the tips, wiping the comb on a white paper towel after each pass so you can see what you’re catching.
- Comb through twice per session. The second pass catches anything the first one missed.
- Repeat every 3 days until you’ve had four consecutive sessions with no lice found.
Expect each session to take 10 minutes for short hair and up to 30 minutes for longer hair. The every-3-day schedule works because it catches nymphs after they hatch but before they’re mature enough to reproduce.
Combining Methods for Best Results
The most effective strategy for most families is using a medicated treatment and combing. Apply the product as directed, then follow up with thorough wet combing to physically remove as many nits and stunned lice as possible. This covers both bases: the chemical kills what it can, and the comb catches what the chemical misses, including resistant lice and eggs cemented to the hair shaft.
No lice treatment, chemical or otherwise, removes nits reliably on its own. The eggs are glued to hair with a cement-like substance that shrugs off shampoo and rinsing. Combing is the only way to get them out.
Cleaning Your Home
Lice can only survive off a human head for about 1 to 2 days, so you don’t need to deep-clean your entire house. Focus on items that touched the infested person’s head in the two days before treatment:
- Bedding, clothing, and towels: Machine wash in hot water (at least 130°F) and dry on high heat.
- Items you can’t wash: Seal them in a plastic bag for two weeks. Any lice or nits will die without a human host well before then.
- Combs and brushes: Soak in hot water (at least 130°F) for 5 to 10 minutes.
You do not need to spray furniture, bag every stuffed animal in the house, or treat your car. Lice spread through direct head-to-head contact, not by jumping off pillows. Concentrate your energy on treating the person, not the environment.
What About Natural Remedies?
Tea tree oil, neem oil, anise oil, and several other essential oils have shown insecticidal activity against lice in laboratory studies. Neem oil in particular has documented effects against nearly 200 insect species. However, lab results don’t always translate to real-world effectiveness. Concentrations, application methods, and exposure times vary wildly between products, and none of these oils are FDA-approved for lice treatment. There’s no standardized dosing or formulation you can rely on.
Suffocation methods like coating the hair in mayonnaise, olive oil, or petroleum jelly overnight are widely shared as home remedies. The idea is to block the louse’s ability to breathe. Results are inconsistent, these methods are messy, and they do nothing to nits. If you choose to try a natural approach, pair it with diligent wet combing every 3 days for at least two weeks. The combing is likely doing most of the actual work.
Preventing Reinfestation
The most common reason lice “come back” is that treatment didn’t fully clear the original infestation, often because the second application was skipped or mistimed. The second most common reason is re-exposure from close contacts who haven’t been checked. Anyone living in the same household as an infested person should be examined, and anyone with live lice or nits found within a quarter inch of the scalp should be treated at the same time.
Teach kids to avoid head-to-head contact during play and sleepovers, and not to share hats, helmets, hair accessories, or earbuds. These are the primary transmission routes. Lice don’t jump or fly; they crawl from one head to another, and they need direct contact or a shared item that touches hair to make the trip.