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Head Lice

What are Head Lice?

Head lice (Pediculus humanus capitis) are tiny, wingless parasitic insects that live among human hair and feed on small amounts of blood from the scalp. A single louse is the size of a pinhead when it hatches and 3mm long when fully grown.  Anyone can be infested with head lice, but the problem is more common in children. Head lice are contagious and spread easily from head to head contact. Humans are the only suitable host so head lice cannot be spread to or from pets and animals. Head lice can live in clean or dirty hair – a head lice infestation is not a reflection of hygiene standards.

Life Cycle

Lice eggs (nits) are laid on hair shafts close to the scalp for warmth, they look like tiny yellow, tan or brown dots before hatching.  

These eggs hatch 7-10 days later. The empty nits remain glued to the hair, they look white and become more noticeable as the hair grows and they are moved further away from the scalp. These empty shells can sometimes be confused with dandruff; however they can’t be removed by brushing or shaking off.

Head lice then take 6-10 days to become fully grown, during this time they feed by biting the scalp and sucking small amounts of blood. Once mature, head lice can transfer from head to head. They do not swim, jump or fly so rely on head to head contact to transfer and survive.

A female can mate and lay eggs as early as 7 days after hatching. Females are usually larger than males and can lay up to 8 nits per day.

Adult lice can live up to 30 days on a person’s head while feeding on blood several times daily. Without blood meals, the louse will die within 1 to 2 days off the host.


Head lice can be difficult to detect. Itching of the scalp is often associated with head lice. This is not a reliable method of diagnosis. The itching is not caused by lice biting the scalp; the itching is actually as a result of allergy to the lice and may take up to three months to develop. Some people are not allergic and may not experience this symptom.

Finding unhatched eggs alone is not enough to diagnose an active head lice infestation as it is difficult to distinguish between unhatched eggs and empty shells which can remain attached to the hair even after successful treatment. To confirm an active infestation a live louse must be detected using a reliable method such as detection combing.


We offer a range of products suitable for the treatment and prevention of head lice.

Hedrin products are specifically formulated to kill head lice without the resistance which can sometimes be associated with traditional insecticides, which act by poisoning the louse. The active ingredients in these products work by physically killing the lice. Hedrin products are also free from solvents that can cause problems in some asthma sufferers.  Hedrin® ONCE Spray Gel contains the active ingredient Dimeticone (4%) which works by disrupting the process of water management by coating the lice, causing them to become permanently immobile, and blocking the spiracles (tiny passages in the exoskeleton) preventing them from getting rid of excess water. As a result, any lice that have recently fed suffer from death by gut rupture and, the ones that haven’t, die of starvation. The gel can be used as often as needed without lice developing resistance. Hedrin® Treat & Go Foaming Mousse is the easy, no fuss way to rid of head lice and their eggs. It's light, non-sticky foam which spreads quickly and easily on to hair. Has no nasty smell and is skin friendly. The active ingredient Activdiol (5%) works by dissolving the waxy coating that covers the head lice. This waxy layer is what maintains the delicate internal water balance of the insect and prevents too much water from evaporating. Death by dehydration occurs once this waxy coating has been damaged. Hedrin® Protect & Go Conditioning Spray actively protects children against head lice while keeping hair looking healthy too. The active ingredient is Activdiol (1%). This product can be used regularly, and is recommended during social activities such as sleepovers, parties and back to school time in order to prevent head lice infestations.

Full Marks Solution is clinically proven to kill head lice in a ten minute treatment time. It has no nasty smell and contains no traditional pesticides. Full Marks Solution Spray gives the same benefits but in an easy to use applicator.  These products contain the active ingredient Cyclomethicone
Isopropyl myristate which works to eliminate head lice by damaging the outer coat of the lice causing them to dehydrate, shrink and die. Full Marks products may be suitable for use for people with asthma, eczema or sensitive skin.

Lyclear® Sensitive Treatment attaches onto the respiratory orifices of head lice and eggs to suffocate them and penetrates into the heart of the eggs to stop their development. This product is gentle to hair and skin and leaves the hair soft and easy to comb. Dermatologically tested and contains no perfumes, no alcohol and no pesticides.

Nitty Gritty Aromatherapy Head Lice Solution contains nothing but safe, proven natural ingredients, blended in a nut-free base with neem and added wheatgerm to leave your hair in shiny tip-top condition. Pesticide free. Used in conjunction with the Nitty Gritty NitFree Comb it gives unbeatable results. This solution helps the comb to glide smoothly and effortlessly through any hair type. The award-winning Nitty Gritty Comb quickly and easily removes head lice and unsightly nits (empty egg cases) and also extracts 'live' head louse eggs before they hatch. Nitty Gritty Defence Spray is a carefully chosen blend of essential oils for daily use. It smells nice to people - but not to lice! This spray can be used after an infestation has been cleared or just as a general head lice deterrent for the whole family.