Head lice lay their eggs, called nits, directly on strands of hair, using a glue that is extremely strong. In fact, the glue is so strong that it is commonly said that the lice “cement” their eggs in place.
Removing the eggs, or even the empty eggshells, from hair is difficult. There are a number of nit-removal products you can buy that loosen the glue. A study published this year in the Journal of Medical Entomology compared these nit-removal products with ordinary hair conditioners. Surprisingly, hair conditioners are just as effective in removing louse eggs as special nit-removal products.
You still usually need to use a product to kill the lice themselves, but since these products are not that effective in killing eggs, daily use of shampoo and hair conditioner, then combing with a fine-toothed comb, plays an important part in eliminating these pests.