Head lice affect an estimated 6 to 12 million people each year in the United States alone, predominantly children. Traditional over-the-counter treatments like permethrin are becoming less effective due to growing resistance — and ivermectin is emerging as a highly effective alternative.
How Ivermectin Kills Head Lice
Ivermectin targets glutamate-gated chloride channels in the lice’s nervous system, causing paralysis and death. When taken orally, ivermectin circulates in the bloodstream and enters the skin and sebaceous glands, where it contacts and kills feeding lice. It also penetrates the hair follicle environment where nits (eggs) are laid.
Oral vs Topical Ivermectin for Lice
Ivermectin is available both as an oral tablet and as a 0.5% topical lotion. Oral ivermectin is a convenient single dose with systemic action, typically requiring two doses 7 days apart. Topical ivermectin lotion is applied directly to dry hair for 10 minutes then rinsed — a single application has been shown to be highly effective in clinical studies.
Clinical Evidence
A large randomised controlled trial found that a single application of 0.5% ivermectin lotion was significantly more effective than malathion lotion — the then-standard treatment — with a success rate of 73.8% versus 17.6% after two weeks. Oral ivermectin has also shown strong results, with two doses achieving cure rates above 95% in multiple studies.
Ivermectin vs Permethrin for Head Lice
Permethrin resistance is now widespread in head lice populations in many countries, reducing the effectiveness of traditional treatments. Ivermectin uses a completely different mechanism of action, making it effective even against permethrin-resistant lice. This is one of the main reasons ivermectin has gained traction as a treatment of choice.
Dosage for Head Lice
For oral ivermectin, the standard dosage for head lice is 200-400 mcg/kg of body weight. Two doses given 7 days apart are typically recommended to catch any lice that hatched from eggs after the first dose. See our ivermectin dosage guide for a full weight-based reference.
Is Ivermectin Safe for Children?
Oral ivermectin is approved for use in children weighing 15 kg (33 lbs) or more. The topical formulation can be used in children as young as 6 months. As with all medications, care should be taken to calculate the correct dose based on body weight.
Buy Ivermectin Online
Dealing with a resistant lice infestation? You can buy ivermectin online through our store with fast, discreet delivery. Also read our guide on ivermectin side effects before starting treatment.
