While some types of hair dry may kill live head lice, it does not remove their eggs. You likely need to remove nits with a fine-toothed comb.
Few words strike as much mortal terror into the hearts of parents than “your child has head lice.”
Anyone with hair can get head lice. Children attending preschool and elementary school, as well as their caretakers and those in their household, have the highest risk of infestation.
Head lice are parasitic, wingless insects that live in hair and on the scalps of people. They’re around the size of a sesame seed and range in color from brown to translucent white.
Lice require human blood to survive. They can live as long as 30 days on the scalp. They lay three to five white-colored eggs, called nits, a day.
There have been no studies on hair dye’s ability to kill lice, but widespread anecdotal evidence suggests that it may eliminate them. However, hair dye doesn’t kill nits.
There are many different types of hair dye. The type used to kill lice is permanent hair dye.
Permanent dye contains ammonia. Ammonia is an alkaline, a corrosive chemical that produces an irritating gas. It may be the reason why hair dye seems to be effective at killing lice.
More permanent hair dye solutions also include hydrogen peroxide, which may also have an effect.
Nits are encased in a hard shell for protection. The chemicals in hair dye aren’t able to penetrate this shell, or detach the natural glue-like substance adhering the shells to hair. That’s why hair dye is ineffective at eliminating nits before they hatch.
Hair bleach contains chemicals, including ammonium persulfate, an oxidizer that removes color from hair. It also contains hydrogen and stearyl alcohol. These ingredients may help kill lice on the scalp, but, like dye, aren’t effective at exterminating nits.
If you wish to use hair dye to try to kill lice, it’s advised that you repeat the process every week until the lice and nits are completely gone.
You should also combine dyeing or bleaching your hair with other removal techniques, such as combing or using vinegar. Keep in mind that there’s no current research to support vinegar in killing lice or loosening the glue that attaches nits to hair. Anecdotal evidence may indicate that vinegar can kill immature lice.
If you’d like to try to use hair dye as a lice removal treatment, follow these steps:
- Start with vinegar. Saturate your entire scalp with a 50-50 solution of water and vinegar that has 5-percent acidity. Work the vinegar mixture down each hair shaft near the scalp, behind the ears, and at the nape of the neck. Leave the solution on your scalp for 5 to 15 minutes. If you experience a burning sensation, wash it off immediately.
- Rinse the vinegar and water solution from your hair thoroughly with warm water.
- Use a lice comb to remove as many nits and live lice as you can from your head. Clean and soak the lice comb in very hot water. Make sure it’s completely free of lice and nits before reusing.
- Mix the hair dye according to package directions in a well-ventilated area.
- Saturate your scalp with hair dye. Concentrate on the same areas you focused on with the vinegar solution: the base of each hair, behind and around your ears, and at the base of your neck.
- Thoroughly rinse out the hair dye.
- Comb your hair again with a clean lice comb.
- Use a hot hair dryer to dry your hair. This may help kill off any lice left behind.
If you’re unable to remove every nit within an inch or two of the scalp, you’ll likely have lice again in about seven days.
Dyed hair doesn’t repel lice and won’t stop you from becoming infested if you come in contact with head lice again.
Permanent dyes can cause chemical changes that affect your natural hair color. They can also irritate your scalp and cause allergic reactions. Side effects can occur on the scalp, neck, and face, including:
- hives or welts
These types of side effects may become more severe if you use hair dye or bleach products more often than intended. You may also damage your hair, causing it to thin or dry out if you use hair dye or bleach more than once a month.
When using these products, make sure to use the disposable gloves that typically come with them to protect your hands and other areas of the body that you might touch.
Make sure not to get any product into your eyes, nose, or mouth. It’s also important to avoid breathing in the fumes emitted by hair dyes. Always dye your hair in a well-ventilated area.
Hair dye and hair bleach aren’t recommended for use in children as a lice-removal treatment. Children’s hair is often finer in texture than adult hair, making it more prone to damage from the chemicals in dyes and bleaches. Children may also be more susceptible to chemical reactions affecting the scalp, hair, eyes, and airways.
There are almost as many at-home lice treatments as there are lice in an average infestation. You may have to experiment with several before you find the ones that work best for you.
Like many insects, some lice are becoming resistant to some tried-and-true treatments, such as medicated shampoos and stearyl alcohol. All home lice treatments require the manual removal of lice and nits with a fine-toothed lice comb.
Some common treatments include:
- Over-the-counter lice elimination kits, such as Nix, use varying types of insecticides, and some may not be appropriate for babies, toddlers, small children, and pregnant or breastfeeding women. Check with a doctor if you have concerns and follow package directions for safety.
- Coating the scalp with olive oil or mayonnaise may suffocate lice. This anecdotal remedy, which isn’t proven effective, requires that you leave these substances on the hair for 24 to 48 hours under a shower cap. It may help to braid long hair or pin it up after treating the scalp.
- Coconut oil hasn’t been scientifically proven to be effective, but it’s natural and nontoxic. To increase effectiveness, try using it after treating your hair with a vinegar solution.
- Essential oils, such as peppermint, lavender, or rosemary may repel lice. You can try using essential oils diluted with a carrier oil as a smothering treatment.
If at-home treatments such as Nix and diligent combing don’t work, talk to a doctor about prescription medications that may help.
Hair dye and bleach haven’t been scientifically proven to kill lice. However, anecdotal evidence indicates that they may be effective. They’re not, however, able to kill lice eggs, known as nits.
Other lice removal treatments will most likely be more effective. If you wish to try hair dye or bleach for lice removal, make sure to also use a lice comb to remove lice and nits, and continue to watch for leftover or live lice.