Does Hair Dye Kill Lice? Here’s What Experts Say 2023

Head lice^[1] is a parasitic insect that lives on the hair and scalp of people. Lice feed on human blood several times daily and can live for up to 30 days^[2] on a person’s head. Lice infestations are most common in young children and can affect their household members and other close contacts.

Most head lice medications can be purchased without a prescription at a local drug store. However, some people use alternative treatments like hair dye to eliminate lice. But does hair dye kill lice and eggs?

Hair dye may potentially kill head lice, but it’s unlikely to kill their eggs or work as well as traditional treatment methods. If you decide to use hair dye to kill lice, it’s a good idea to be aware of the risks and deep condition your hair to minimize potential side effects.

Keep reading to learn more about the effectiveness and safety of hair dye in treating head lice.

How Does Hair Dye Affect Lice?

While hair dye is typically used for changing hair color, there is some anecdotal evidence that it may also kill lice.

So, does hair dye kill head lice?

No clinical trials address the effectiveness of hair dye in killing head lice. However, there are several potential mechanisms by which permanent hair dye may affect lice. 

Certain chemicals present in hair dye, such as ammonia and hydrogen peroxide, may be highly toxic to lice, killing insects. Ammonia^[3] is a highly toxic gas or liquid that, when concentrated, is corrosive. Hydrogen peroxide, commonly found in permanent dyes and hair bleach, is believed to have similar effects. While one study found it effective for treating sea lice,^[4] the two are unrelated. No studies have shown similar effects in head lice.

Even if hair dye can kill lice, it’s unlikely to eliminate all the bugs, as lice can be incredibly resilient. Furthermore, lice eggs, called nits, are unlikely to be killed by hair dye as the chemicals may not penetrate the hard shell encasing the nits. Nits that remain on the scalp can hatch 9-10 days^[5] later, allowing the lice infestation to continue. 

How To Use Hair Dye To Treat Lice

If you decide to use permanent hair dye to eliminate head lice, here are some steps to consider.

• Use a lice comb on wet hair to remove as many nits and live lice from your head as possible. This method, known as wet combing,^[6] can be an effective way to physically remove lice and nits from the hair.
• Clean and soak the lice comb in hot water for five to ten minutes^[7] between uses.
• Mix the hair dye in a well-ventilated area according to the instructions provided in the hair dye kit.
• Apply the dye, ensuring thorough scalp and hair saturation.
• Allow the dye to process on your hair for the recommended time and rinse.
• Comb through your dyed hair again with the lice comb.
• Blow dry your hair on high heat to help kill any remaining lice.
• Consume plenty of superfoods for hair and use conditioning products for hair in between dyes to keep your hair healthy.

Remember, though, that the Food and Drug Administration does not approve hair dye to treat head lice, and its effectiveness has not been validated in clinical trials.

Precaution Of Using Hair Dye For Head Lice

Permanent hair dye, sometimes called coal-tar^[8] dye, penetrates the hair to change its color. It is more commonly associated with adverse reactions^[9] than semi-permanent and temporary hair dyes.

Contact allergies are a common side effect^[9] of permanent hair dye and may include skin irritation, hives, and swelling. Perform a patch test before every use to test for potential skin reactions.

Avoid applying hair dye on eyelashes or eyebrows, as hair dyes can cause eye injuries.^[10]

To minimize safety risks^[10] when applying hair dye, consider the following:

• Wear gloves when applying hair dye.
• Mix and apply your hair dye in a well-ventilated area.
• Do not leave the dye on the hair longer than instructed.
• Rinse the scalp well with water after using hair dye.
• Do not dye your hair if your scalp is sunburned or irritated.
• Wait at least two weeks after bleaching, relaxing, or perming your hair before using hair dye.

Hair dye shouldn’t be used to treat lice in children unless recommended by a healthcare provider. 

Other Methods For Killing Lice

FDA-approved treatments^[11] for head lice include over-the-counter and prescription medications in shampoo, deep conditioner, and lotion formulas. OTC lice treatment kits like Rid and Nix^[7] are commonly recommended and can be purchased at most drug stores.

Rid contains pyrethrins, which are only approved for use in children over the age of two. Nix contains permethrin and is approved for use in children two months and older.

One 2016 randomized control trial found that, while permethrin shampoo was more effective, combining coconut oil and vinegar^[12] may be an effective alternative treatment for head lice.

Prescription medications may be considered if OTC treatments have been used according to instructions without success.

To prevent re-infestation after treatment:

• Wash clothing, bedding, hats, and other items that the infested person used during the two days before treatment.
• Soak brushes and combs in hot water for five to ten minutes.
• Vacuum the floor and furniture, focusing on the areas where the infested person sat or slept.
• Don’t forget to clean the inside of the car.

Other natural methods, such as mayonnaise, olive oil, margarine, and butter, are believed to kill lice by suffocation. However, there is no solid evidence^[13] to confirm these effects

If you need help deciding which treatment to use or how to use it, consult a healthcare provider or pharmacist for guidance. It is also a good idea to consult your healthcare provider if you are pregnant, breastfeeding, or need to treat a young child.

Conclusion

So, does dying hair kill lice?

While some people claim that hair dye kills lice, no clinical studies confirm these claims. Hair dye contains certain chemicals like ammonia and hydrogen peroxide that may kill head lice. However, hair dye chemicals alone are unlikely to kill lice eggs called nits.

If you are looking for an effective head lice treatment, consider options that are FDA-approved and supported by scientific evidence. If you decide to use hair dye for lice removal, use a lice comb to remove lice and nits both before and after applying the dye.

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