The Anatomy and Growth Cycles of Hair and Laser Hair Removal.

For a better understanding of how laser hair removal works, we must gain an insight into hair anatomy, physiology, and growth cycles.

The human body surface is almost covered with hair follicles, except for the palms of the hands and soles of the feet. Each person has approximately 5 million individual hair follicles. Hair follicles may be straight, wavy, helical, or spiral. Caucasian people typically have thinner hair shafts than persons of Asian or African American heritage. The hair density can also vary in a given skin surface. All of these factors along with the skin type (ethnicity) play a role in determining the right laser and settings to be used when performing laser hair removal.

There are primarily 2 types of hairs on adult bodies. Vellus hair can be found over the entire body and appears as soft, fine, short hairs that are nonpigmented or very lightly pigmented and are almost invisible. Terminal hair is the longer, coarser, and more darkly pigmented hair found on the scalp, underarm area, and groin. Vellus hairs outnumber terminal hairs greatly; however, terminal hairs are more important, as they are responsible for the appearance of hair on the body since they can be a source of embarrassement.

Hair on the body has 3 distinct development cycles: anagen, catagen, and telogen. As hairs progress through these cycles,they are affected differently by treatment with laser hair removal. Anagen is the cycle in which active hair growth occurs. Follicular matrix cells are actively producing cells that will make up the growing hair. During the catagen (the dormant phase), matrix cells degenerate and the bulb begins to die, causing the hair follicle to shrink. Telogen is the final resting phase of the hair follicle. Growth of the hair has stopped, and the follicle becomes inactive. During telogen, the hair is released from its attachment to the skin and sheds.

The process begins again in anagen to form a new hair. The length of time spent in each phase depends upon the location of the hair. On the scalp, hair follicles spend up to 10 years in anagen, but on the trunk, brow, and limbs, anagen lasts no longer than 6 months. Catagen lasts only 2-3 weeks, and telogen lasts from 3-4 months.

Up to 90% of hairs in a given body location can be in the anagen phase at a given time. This is a very important fact in the laser hair removal process since hairs in the anagen phase of development are very responsive to laser treatment. Due to this FUNDAMENTAL FACT, MULTIPLE TREATMENTS are necessary to treat all hair follicles for a given area.

Katy Issa
www.AuraLaser.com