What is Laser Hair Removal?

Dr. Bernstein Contributed By: Dr. Eric F. Bernstein
Clinical Associate Professor, University of Pennsylvania
School of Medicine
President, Yale School of Medicine, 1986
Medical Director, Mainline Cosmetic Laser Center
Lasers produce pulses of high-energy light that
cause hair to become dormant
Various types of lasers are used based on patient
skin and hair color
Results depend upon the experience of the
practitioner
A single treatment may reduce thickness and density of hair
Multiple treatments will provide best results

How laser hair removal work?
Laser hair removal is the use of laser energy to produce long-term hair reduction. This is accomplished by producing heat in the hair, which is transferred to the hair follicle,which in-turn produces inflammation, and this inflammation sends a signal to the hair follicle to go into the resting (telogen) phase.

What is a laser, really?
First of all, what is a laser? A laser is a device that produces light of a single color or wavelength. In dermatology, these lasers produce pulses of high-energy light that is taken up by the desired target. In the case of hair removal, the target is the melanin pigment contained within the hair shaft.

A delicate balance
The tricky part of laser hair removal is targeting the hair shaft without damaging the melanin pigment in the surface of the skin. Thus the laser light has to be on long enough to heat the hair, but not too long to allow that heat to spread to the surrounding skin causing damage.
In addition, the darker a patient’s skin, the more difficult it is to avoid injuring the surface of the skin while treating the hair. For this reason, there are three main types of hair removal lasers that are used today, and depending on the thickness of the hair and the color of the skin, one laser may provide benefits as compared to another.

When Performing Laser Hair Removal, Experience Matters
In addition to lasers, intense pulsed light sources are also used for hair removal. These light sources do not emit a single color or wavelength of light, but emit light containing many colors. It may be more difficult to predict the outcome and avoid complications when using light sources that contain many wavelengths of light. However, the results with any device depend upon the experience of the practitioner.

How many treatments?
Normally, a series of three to five treatments are administered at four to eight week intervals depending upon the location of the hair. Following the initial series of treatments, subsequent treatments are administered, usually at longer and longer intervals. Some number of maintenance of treatments may be needed to keep all the hair away in a given area. After a single treatment, the hair in a given area is usually reduced in amount and thickness for a very long period of time. However, it may not be completely gone. To keep an area completely devoid of hair, maintenance treatments are always required. These maintenance treatments may eventually be required at only yearly intervals or even longer. This depends on the area being treated as well as the individual. As with any other traits in an individual, the frequency of maintenance treatments varies considerably from person to person.

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