What is the biological reason why laser hair removal is completely ineffective on white, red, or very light blonde hair?

Laser devices require a “conductor” for the light energy they produce to reach the hair follicle, and this conductor is the melanin (color) pigment inside the hair. In white hair, melanin is completely absent; in blonde and red hair, a different type of pigment called “pheomelanin,” which has a very low capacity to absorb laser light, is dominant. When the laser beam hits these hairs, it cannot be absorbed, cannot turn into heat, and is reflected without causing any damage to the hair follicle. Therefore, people with white or very light-colored hair should use needle epilation (electrolysis) instead of laser epilation.