How does the laser work in laser hair removal?

Lasers for hair removal are engineered to target the melanin in the hair shaft, not the actual follicle or skin. They do this by using specific wavelengths of light for specific durations of time.

The specific wavelengths of light do not target white, gray, silver, and blond hairs, which is why they are poor candidates for treatment. If there is enough melanin in the hair shaft (that is the hair is dark enough and thick enough to contain enough melanin), then it is able to absorb enough laser light energy to generate enough heat to conduct that heat to the follicle that surrounds it. If the portion of the follicle (when the hair is in its growth phase) that is responsible for producing hair growth is heated to a high enough temperature then the follicle should no longer be able to generate hair growth.

Published on Jul 11, 2012

Most laser hair removal systems destroy dark pigment, so if you have light skin and dark hair, they destroy the dark pigment which ultimately destroys the hair follicle and essentially "kills" the hair. All hairs grow at different rates and at any one time they are in their growth phase, which is the phase when the laser destroys the follicles. Thus, you need multiple treatment times to get more of the hairs in that phase of their cycles. It is never permanent, and continued treatments are needed over time.

Published on Jul 11, 2012

The laser can distinguish between the skin and the hair, and goes for the dark color. That's why the ideal candidate is a fair skinned person with dark (brown/black) hair. The area being treated should be shaved prior to treatment, so the laser can hit the hair in the follicle and not the outside hair. When the heat travels down the hair to the follicle the follicle is destroyed and unable to grow new hair. The hair grows in 3 cycles, not all hairs are growing at one time, therefore it takes multiple treatments for full hair removal.
None of the above is not intended as medical advice. If you have a medical concern, please consult your doctor.

Published on Jul 11, 2012

The laser light is attracted to the darkness of the hair. This is why the best candidate is a light skinned dark haired patient.
It takes several treatments but gradually thins the hair with each treatment. The light goes down the hair shaft to destroy the hair bulb. The hair needs to be treated in a certain stage of the growing cycle. This is why it takes several treatments.

Published on Jul 11, 2012

Laser hair removal works when the bulb (base) of the hair follicle is heated up to the point where it damages the blood vessel (the vein) that brings blood to the hair. Once this vein is damaged and no longer feeds blood to the hair, it will not regrow.

The heat from the laser light is concentrated at the base of the hair follicle because this is the darkest color within the skin. Laser (light) energy absorbs into dark colors very easily (similar to a black t-shirt on a sunny day). Because the base of the hair follicle is the
darkest area of the body, it absorbs most of the light and heat from the laser. The heat avoids the rest of the skin because it is lighter in color. This phenomenon is called "selective photothermolysis" or more simply selective heating.

Published on Jul 11, 2012