Do nit removal formulations and other treatments loosen head louse eggs and nits from hair?

Eggs of the head louse, Pediculus capitis De Geer (Phthiraptera: Pediculidae), are difficult to remove because the female louse fixes them to hairs using a proteinaceous secretion that hardens within seconds. The persistent eggshells are harmless but unsightly and are often mistaken for an active infestation. Combing with a fine comb (nit comb) does not readily remove the eggs or empty eggshells because of the resilience of the fixative and both folk remedies and medical products have claimed to facilitate their removal. Measurement of the force required to initiate sliding of the egg fixative using a slip-peel tester was unable to detect evidence that any of three products which claimed to have egg-loosening properties (Step 2 Nit Removal System, Clear Lice Egg Remover, RID Lice Egg Loosener Gel) had any activity or exerted any effect on the egg fixative beyond the lubricating effects conveyed by water or conventional hair conditioner.