The thulium laser is an infrared laser and the main target tissue for skin absorption is water. Since the water content of the dermis is higher than that of the epidermis, the accumulation of heat and temperature rise in the dermis is higher than that in the epidermis during thulium laser treatment. Since the water content of epidermis is smaller, it will not be damaged by intense heating and cause edema and injury in the heating process. The skin will only be slightly reddened, with a certain sense of heat and pain, but it will not sting, burn or even be damaged.

The 1927nm fractional mode is characterized by the use of a fractional handle to focus the laser onto a small spot (approximately 0.1-0.15mm in diameter) to irradiate the skin, achieving a non-ablative or micro-ablative effect, mainly for skin rejuvenation and wrinkle reduction. If the laser is applied for a long enough time, a micro-ablative effect is produced. If the duration of action and energy density are reduced, a thermal coagulation vertical band may be produced, which activates collagen and shrinks the skin.

After the treatment, the skin experiences a series of lasting effects. First, the moisture in the epidermis heats up, causing some proteins to micro-coagulate. This simultaneously causes melanin to be damaged by the heat and then gradually discharged from the surface of the body, where it is phagocytosed and metabolized by the body's macrophages. Second, because it penetrates deep into the dermis and slightly stimulates the dermal papillary layer, it not only accelerates collagen synthesis, but also stimulates division.

The 1927nm laser, which primarily uses thermal coagulation instead of stripping and vaporization, is a safer infrared laser.