Which types of hair do not respond well to hair reduction treatments?

The response that states vellus, blonde, red, and grey hairs do not respond well to hair reduction treatments is accurate due to the characteristics of these hair types.

Vellus hairs, often referred to as "peach fuzz," are fine and short, making them less likely to be effectively targeted by hair reduction technologies, which typically rely on a contrast between the hair and the skin for effective results. Treatments like laser hair removal work best on darker, coarser hairs because they absorb more light and heat, leading to more effective hair destruction at the follicle level.

Blonde and red hairs often lack sufficient pigmentation, which means they do not absorb light energy as effectively. Grey hairs, being devoid of pigmentation altogether, similarly do not respond well since most hair reduction treatments, including laser techniques, rely on the contrast between the pigment in the hair and the surrounding skin to achieve optimal results. As a result, these hair types are much less likely to see significant reductions in growth compared to darker, more pigmented hairs.

In contrast, thick, dark brown, and black hairs are prime candidates for these treatments. Their strong pigmentation allows for the absorption of the energy used in these procedures, making them much more responsive to hair reduction efforts.