Lice can be treated using specialized combs, medicated shampoos, or home remedies like oils. But there’s no single treatment that can get rid of lice right away.

Lice are tiny parasites that live in human hair and feed on blood. They also lay eggs called nits that can stick to your hair. As many as 12 million lice infestations are documented each year in the United States.

Read on to learn how long it takes to get rid of lice, what their life stages mean for treatment length, and when to contact a doctor.

There’s no simple answer to how long it takes to get rid of lice. You’ll usually need to treat lice once, then again 9–10 days later to kill all the lice and eggs in your hair. But note that a second treatment isn’t needed or recommended when using certain medications.

Lice eggs hatch after about 1 week. You’ll probably need to treat your hair for at least a week to make sure you kill all the eggs that may be in your hair.

Lice can live for up to 30 days after hatching. You may need to wait another few weeks after treatment to be sure all lice have been killed.

Some medications kill lice but not their eggs, and eggs can hatch into more lice even after the first infestation is treated.

In most cases, you’ll need to treat your hair and then check for lice and eggs for 3–4 weeks before an infestation has been eradicated.

Here are the lice life stages you can use to estimate how long you’ve had lice and how long it might take to treat an infestation.

Eggs

Eggs hatch after about 1 week.

Under a magnifying glass, lice eggs are about the size of a pinhead and look like yellow-white ovals attached to the bottom of hair strands near the scalp.

Nymphs

Nymphs are newly hatched lice that appear gray rather than yellow or white.

After hatching, lice go through the nymph stage for about a week before becoming adult lice. They’re about the same size as an egg when they first hatch, but slowly grow to the size of an adult louse.

Adults

Nymphs mature into adult lice after about a week and live for up to 30 days.

Adult lice are bigger and easier to identify than eggs or nymphs. They’re also usually white or tan rather than gray or yellow.

Here are some treatments for lice that you can do at home.

Checking for lice

Checking your hair regularly for lice can help you remove them quickly. The most effective way to check for and remove lice is by wet-combing. This is done by wetting your hair and using a specialized lice comb with tiny teeth to comb through each strand to find and remove lice and eggs from your hair.

Wet-combing your head can take several hours.

Over-the-counter medications

Over-the-counter (OTC) medications for lice include pyrethrins with piperonyl butoxide and permethrin lotion.

Pyrethrins with piperonyl butoxide can be used as shampoos or hair rinses for lice and nymphs (but not eggs). Permethrin lotion (1%) can be used as shampoos, ointments, or hair rinses for lice and nymphs (but not eggs).

Prescription medications

Prescription medications for lice include:

  • benzyl alcohol lotion (5%) applied to the hair as a cream or ointment to kill lice and nymphs
  • ivermectin (pill or 0.5%)taken by mouth or applied to dry hair as a cream or ointment
  • malathion lotion (0.5%) applied to the hair to kill lice and most eggs before they hatch
  • spinosad topical treatment (0.9%) applied directly to the hair and kill both lice and eggs

Home remedies

Here are some effective home remedies for head lice:

  • wet-combing
  • using 4% dimethicone silicone gel
  • applying olive or almond oil to your hair
  • using essential oils like tea tree oil or lavender oil while wet-combing
  • washing bedding and household objects you come into contact with while treating lice
  • vacuuming areas in your home where lice may be

Contact a medical professional if you:

  • still have lice after two treatments or after 1 month
  • have persistent pain or itching on your scalp
  • have discharge from scabs or sores on your scalp
  • have a fever
  • have swollen lymph nodes

Here are some of the most frequently asked questions about lice and itching.

What kills lice eggs?

Malathion lotion and spinosad topical treatment are two of the most effective treatments for killing both lice and eggs.

Can you get rid of lice overnight?

No, you can’t get rid of lice overnight. You’ll usually need to use treatments for a week or more before you kill all the lice and eggs that are in your hair.

Will lice go away if you wash your hair?

No, washing your hair won’t usually make lice go away immediately. Use a lice comb on wet hair and continue washing your hair regularly for the best results in killing lice. If they still don’t go away, use OTC or prescription lice treatments.

How do you know when the lice are gone?

Use a lice comb to examine your hair and scalp for any lice or eggs. If you don’t see any small white insects or white spots, you probably don’t have lice anymore. Keep in mind that you might feel some tickling or itching on your head for a few days after you treat a lice infestation.

It usually takes several weeks to treat a lice infestation. Try to contact a doctor if you’re still finding lice after several treatments or have persistent pain and itching.