The dermis is the dense layer of skin found below the epidermis layer and above the subcutaneous tissues. It is split into two parts, the papillary dermis and the reticular dermis. The upper half of the dermis, or the papillary dermis, consists of fine and loosely arranged collagen fibers. This layer also includes areolar connective tissue that contains blood capillaries or Meissner’s corpuscles.
Beneath the papillary dermis is the reticular dermis, which is composed of dense irregular connective tissue, tightly packed collagen fibers, as well as dermal elastic fibers. This area is typically much thicker than the papillary dermis, and is responsible for the mechanical tightness of our skin. The reticular dermis is known for its strength and elasticity, which are properties that come from the layer’s protein fibers, which can be found weaved throughout. It is this area where sweat glands, nails, receptors, and the roots of the hair lay.
The dermis is an important aspect of laser hair removal because lasers need to penetrate the reticular dermis without damaging the epidermis. This is done with medical lasers that produce longer wavelengths. These wavelengths are able to bypass the epidermis without affecting the skin’s color or texture, and they target the pigment of the hair follicles in the dermis layer. When the melanin in the hair follicle absorbs the laser, these hairs can be destroyed without damaging the skin. This is why dark, coarse hair is a better candidate for laser hair removal than light peach fuzz. Hair that contains more melanin, or color, attracts the lasers better.