Lice infestations are very common, especially among school-aged children. It’s estimated that 6-12 million lice infestations occur every year in the US alone in children aged 3-11 years old.
As a parent, if your child comes home from school with a note saying there’s been a lice outbreak in their classroom, your first reaction is probably “Oh no, not lice!” Immediately you start thinking about how to get rid of lice fast and prevent an infestation on your child’s head.
A common question many parents have is: can I just dye my kid’s hair to kill the lice? It seems like a simple solution since the chemicals in hair dye are strong enough to alter the color of your hair, so why wouldn’t they kill lice too?
While this may sound logical, the truth is that hair dye does NOT actually kill lice. The active ingredients in hair dye like ammonia and hydrogen peroxide will do nothing but change the color of live lice and their eggs.
In this comprehensive article, we’ll cover:
- What are head lice
- Does hair dye kill lice?
- Why hair dye doesn’t kill lice
- Can hair dye kill lice eggs?
- Is hair dye safe for lice treatment?
- Alternative lice treatments that work
What Are Head Lice?
Before diving into whether hair dye can kill lice, let’s start with some background on what head lice are and how they infest hair.
Head lice are tiny parasitic insects that live on the human scalp and feed on blood. An adult louse is about the size of a sesame seed and can be difficult to spot with the naked eye. Lice appear translucent white or tan in color.
Female lice can lay up to 10 eggs per day, cementing them at the base of the hair shaft near the scalp. These eggs are called nits. Nits hatch within 1-2 weeks, releasing baby lice called nymphs.
Lice spread quickly through close head-to-head contact and sharing personal items like hats, helmets, hair accessories, towels, and brushes. Lice do not have wings or jumping legs so they cannot fly or jump from head to head. Their legs are specially adapted to cling tightly to hair strands.
Some common signs and symptoms of lice infestation include:
- Itchy scalp, especially behind the ears and at the nape of the neck
- Tickling feeling that something is moving in the hair
- Irritability and difficulty sleeping
- Small red bumps or sores on the scalp from scratching
- Seeing live lice crawling through hair or nits glued to hair shafts
Left untreated, a lice infestation can persist for months. Frequent itching and scratching can lead to skin irritation, sores, and even secondary bacterial infections.
Now let’s look at the common question many parents have about using hair dye to treat lice…
Does Hair Dye Kill Lice?
There are many home remedies for lice floating around on the internet, including using hair dye as a DIY treatment. The logic is that the strong chemicals in hair dye should kill lice, just like chemical lice shampoos.
But does hair dye actually kill lice?
The short answer is no, hair dye does not kill lice. The active ingredients in hair dye like ammonia and hydrogen peroxide do not have any effect on killing lice or nits.
Some types of hair dye may contain small amounts of pyrethrin, a compound commonly found in some medicated lice shampoos. However, the concentration in hair dye is far too low to have any insecticidal effect.
At best, hair dye might make lice an interesting color, but it will not eliminate an infestation. Parents may see killed lice initially after a dye treatment and assume it worked. However, any lice found dead were likely already dying from natural causes, not from the hair dye.
Using hair dye is not an effective lice treatment and will not kill active lice or unhatched nits.
Why Doesn’t Hair Dye Kill Lice?
You may be wondering why the strong chemicals in hair dye have no effect on lice. There are a few reasons why hair dye fails as a lice treatment:
Lice are extremely resistant: Head lice have adapted over thousands of years to withstand chemical toxins and pesticides. Their waxy, protective exoskeleton shields them from any irritating effects of hair dye chemicals.
Hair dye is not formulated to kill lice: Hair dye is designed to alter the color of hair, not kill bugs. The active ingredients like ammonia and peroxide work by chemically reacting with melanin pigment in hair strands. They do not specifically target lice.
Ingredient concentration is too low: Any small amounts of pyrethrin or other pesticides in hair dye are far below the concentration needed to effectively kill lice.
Hair dye cannot penetrate nit casings: Even if the chemicals somehow killed live lice, the unhatched nits would remain unaffected. Hair dye cannot penetrate the thick, protective casings of nits cemented to the hair shaft.
Different formulations: With thousands of hair dye brands and formulas on the market, effectiveness can vary widely. Results seen with one formula cannot be generalized to all hair dyes.
No verifiable research: Currently, there are no scientific studies proving hair dye is an effective lice treatment. Any claims of it working are purely anecdotal.
The bottom line is hair dye and other hair chemical processes like bleaching, permanent waving, etc. do not work to eliminate head lice infestations. The active ingredients in these products are not capable of penetrating the durable exoskeleton of lice or nit casings.
Can Hair Dye Kill Lice Eggs?
Since hair dye doesn’t kill live lice, what about lice eggs – can it kill nits?
The answer is no, hair dye has no effect on killing nits.
Nits are firmly glued to the hair shaft near the scalp by a cement-like substance secreted by the female louse. This protective casing shields the developing nymph inside from any external agents, including chemicals in hair dye.
Even when hair dye makes contact with nits glued to hair strands, it cannot penetrate inside the casing or harm the developing louse inside. At most, hair dye just temporarily changes the color of the nit casing.
Once the incubation period ends, the young nymphs will hatch out as normal. Since hair dye does not kill nits, any eggs left on the hair after dyeing will continue their lifecycle and reinfest the scalp with juvenile lice.
The takeaway is that hair dye does not kill nits or stop them from hatching more active lice. To get rid of lice effectively, medicine or products that penetrate nit casings must be used.
Is Hair Dye Safe for Lice Treatment?
Since hair dye is ineffective against lice, is it at least safe to use for attempted treatment?
The short answer is no—hair dye should not be used as a lice treatment, even though it does not kill lice.
Here are some key reasons why hair dye is unsafe for lice treatment:
- Toxic if swallowed or contacts eyes
- Can irritate scalp, causing redness, itching, and burning
- Increased risk of allergic reaction in kids
- No evidence it works, so unnecessary risk of side effects
- Does not remove nits which perpetuate infestation
- Damage to children’s more delicate hair
The active ingredients in hair dye like ammonia, peroxide, and paraphenylenediamine can be toxic. Accidental ingestion could cause mouth and stomach irritation. Eye exposure may result in anything from mild irritation to permanent blindness depending on the dye composition.
These risks are heightened in children, who are more prone to get hair dye where it does not belong. The sensitive skin and hair of children is also more prone to irritation and damage from chemicals in hair dye.
Since hair dye is ineffective at killing lice, there’s no benefit to justify taking any risks of adverse effects in children. Parents should not use hair dyes in an attempt to kill lice on kids.
Alternative Lice Treatments That Work
While hair dye does not kill lice, fortunately there are safe, proven treatments available that DO eliminate lice and nits.
Here are some of the most effective lice treatment options:
Medicated Lice Shampoos
Over-the-counter medicated shampoos like Rid, Nix, and store brands contain pesticides like pyrethrins or permethrin that kill live lice on contact. However, resistance has made these shampoos less effective over time. They also do not kill all nits.
Suffocation-Based Products
Products like LiceMD or Resultz work by coating the louse’s breathing pores with oils or silicone, suffocating the insect. These products are pesticide