Hair muscle (musculus arrector pili)

When the hair muscle contracts, the hair follicle tilts slightly and the hair stands up. At the same time, the adjacent sebaceous gland is compressed, releasing sebum onto the surface of the hair. This mechanism protects the skin and hair with a fine lipid film. A well-known phenomenon of this muscle contraction is goose bumps, which occur when exposed to cold or emotional stimuli. While the raising of hair in animals has an important function in heat regulation and defense, in humans it is only rudimentary.

Hair muscle and laser hair removal

The hair muscle is not a target structure in laser hair removal. Since it contains hardly any melanin, it does not absorb the light. Instead, the treatment focuses on the melanin-containing structures of the hair root, in particular the matrix and dermal papilla. The hair muscle therefore remains unaffected in its function and is not damaged by the treatment.