Terminal hairs are thick, dark hairs that typically develop during puberty. Everyone is born with vellus hair, which is the light peach fuzz that most people are familiar with. During puberty, an increase in androgenic hormone levels causes these vellus hairs to be replaced with terminal hair, growing in only certain areas of the body. These areas include the pubic area and underarms, which are particularly sensitive to these hormones. Considered to be secondary sex characteristics, males develop terminal hair in more areas of the body than women because their androgenic hormone levels are much higher. Men will also develop terminal hair on their face, stomach, legs, arms, feet, chest, and back during puberty, while women will retain most of their vellus hair.
It is these terminal hairs that are most easily targeted by medical lasers during laser hair removal treatments. Lasers are designed to target the melanin in the hair follicle, which is much easier to detect on darker hairs. Vellus hairs are more difficult for the laser to detect because they contain less melanin, but most areas of a man’s or woman’s body can be treated with laser hair removal, including:
- The upper lip
- The pubic area
- The eyebrows or a unibrow
Each person’s vellus hairs and terminal hairs appear differently, and there are many factors that contribute to the success of laser hair removal treatments.