Nix Ultra is a pesticide-free lice treatment that works by physically smothering lice and their eggs rather than using traditional insecticides. The product uses a silicone-based formula (dimethicone) that coats lice and blocks their ability to breathe, making it effective even against so-called “super lice” that have developed resistance to conventional treatments like permethrin. Here’s how to use it properly from start to finish.
Before You Start
Gather everything you’ll need: the Nix Ultra solution, the fine-toothed nit comb included in the kit, a towel to drape over the shoulders, hair clips for sectioning, and paper towels or a white cloth to wipe the comb on between strokes. Having a good light source and a magnifying glass can also help you spot nits during combing.
Do not use this product on children under 2 months of age. If you’re pregnant or breastfeeding, check with a healthcare provider before using it.
How to Apply the Treatment
Apply Nix Ultra to dry hair. This is different from some other lice treatments that go on wet hair. Dry hair allows the solution to coat lice and nits more effectively without being diluted by water.
Start by parting the hair into small sections. Apply the solution thoroughly to each section, working from the scalp all the way to the ends. Pay extra attention to the areas behind the ears and along the nape of the neck, where lice tend to concentrate. Use enough product to fully saturate the hair. For longer or thicker hair, you may need more than one bottle.
Once every section is covered, leave the treatment on for 10 minutes. Set a timer so you don’t cut it short. After the full 10 minutes, use the included nit comb to remove dead lice and nits before rinsing.
How to Comb Out Nits Effectively
Nit combing is the most important part of the process, and skipping it or rushing through it is the most common reason treatments fail. With the solution still in the hair, divide the hair into four or more sections using clips. Start at the scalp and pull the fine-toothed comb slowly through one small section at a time, from root to tip.
After each stroke, wipe the comb on a white paper towel or cloth. This lets you see what you’re removing (live lice, dead lice, and nits) and keeps you from dragging debris back into clean hair. Rinse or wipe the comb clean between every pass.
Work methodically through every section. For shoulder-length hair, expect this to take 30 to 45 minutes. For very long or thick hair, it can take over an hour. Resist the urge to rush. A thorough combing session now saves you from dealing with a reinfestation later.
Once combing is complete, rinse the product out over a sink using warm water rather than in the shower or bath. This limits how much of the product touches the rest of the body. The American Academy of Pediatrics recommends warm water over hot water for rinsing any topical lice treatment to minimize skin absorption.
When to Repeat the Treatment
Plan on a second treatment 7 to 10 days after the first. This timing is critical. Lice eggs take about 7 to 10 days to hatch, so a second application catches any nits that survived the first round before the newly hatched lice are old enough to lay eggs of their own. Missing this window is one of the most common reasons people think a treatment “didn’t work.”
Between treatments, comb through the hair with the nit comb every 2 to 3 days. Each session helps you catch any lice that may have hatched and gives you a clear picture of whether the infestation is resolving. If you’re still finding live, moving lice after two full treatment cycles, the product may not be working and it’s time to try a different approach. The CDC advises against using the same lice medication more than 2 to 3 times if it isn’t effective.
What to Do Around the House
Lice can’t survive long off a human head, but a few simple steps in the first couple of days prevent stragglers from finding their way back.
- Bedding and clothing: Machine wash and dry anything the infested person used in the two days before treatment. Use hot water (130°F) and the high heat dryer setting.
- Combs and brushes: Soak all hair tools in hot water (at least 130°F) for 5 to 10 minutes.
- Items you can’t wash: Seal stuffed animals, decorative pillows, or other non-washable items in a plastic bag for two weeks. Lice and nits can’t survive that long without a host.
You don’t need to fumigate your house or bag up every soft item you own. Lice spread through direct head-to-head contact, not from furniture or carpets. Vacuuming upholstered furniture and the floor around where the person sits or sleeps is sufficient.
What to Expect After Treatment
Some scalp itching and redness can occur after using Nix Ultra. This is a normal reaction and doesn’t necessarily mean the treatment failed or that lice are still active. Itching from lice bites can persist for a week or more after the lice themselves are gone, because the scalp is still healing from the irritation.
If scalp irritation gets worse rather than better, or if you notice signs of infection like spreading redness, warmth, or oozing, stop using the product. Scratching can break the skin and introduce bacteria, so keep fingernails short (especially for kids) during the treatment period.
Why Nix Ultra Differs From Standard Nix
Standard Nix (the version with the yellow box) contains permethrin, a synthetic insecticide that kills lice through their nervous system. It’s been the go-to over-the-counter treatment for decades, but widespread resistance has made it less reliable. In some communities, the majority of head lice carry genetic mutations that make them immune to permethrin.
Nix Ultra takes a completely different approach. Instead of poisoning lice, it physically coats them with a silicone-based formula that blocks their breathing. Because the mechanism is physical rather than chemical, lice can’t develop resistance to it. This makes it a practical option when standard permethrin treatments have already failed.