The Science and Benefits of Laser Hair Removal
Laser Hair Removal has been around since the late 1990’s. It works by exposing hair follicles to pulses of laser light of various frequencies that destroys the growth mechanism of the hair follicles. The United States Food and Drug Association approved lasers for hair removal in 1997. Over time research has led to more effective tactics to eliminate hair on almost all skin types and many hair colors.
How it Works
The primary principle behind laser hair removal is the selective targeting of tissue with specific wavelengths and pulse durations to destroy the targeted area while leaving the surrounding tissue unharmed. Lasers target the dark target matter, melanin, rapidly heating up the follicles basil stem cells which cause hair growth, while leaving surrounding tissue unharmed.
Melanin occurs naturally in the skin and is what gives skin and hair its color. There are two types of melanin. One that gives hair brown or black color and one that give hair blond or red color. Melanin absorbs the photons of laser light on hair that is black, brown, reddish-brown or dirty blonde and can be effectively removed. White, light blond and light-red hair doesn’t absorb photons of light as well and can be difficult to remove. Laser wordk best with dark coarse hair, and the most ideal candidates have light skin with dark hair.
The FDA has approved lasers for “permanent hair reduction”. They define this as the long-term stable reduction in the number of hairs re-growing after a treatment regimen. Some patients experience hair regrowth of the treated area years after treatment and will need some ongoing maintenance. Most patients experience limited grown over the years and may or may not feel the need for touch-up treatments.
Types of Hair Removal Lasers
There are three basic types of laser hair removal devices and all are similar in effectiveness. Intense Pulse Light (IPL) and diode lasers tend to have a higher incidence of side effect, although temporary. Alexandrite/YAG lasers tend to have many less side effects. All side effects are temporary and are mostly pigmentation changes that return to normal in one to six months.
Electrolysis is an older method of hair removal that has been used for over 100 years. When used at the correct power levels and using the proper techniques it is effective on all hair colors and textures. The downside is that the treatment is very slow, and studies have shown that it takes as much as 60 times more treatment time than modern lasers.
Laser Hair Removal is regulated at the state level. Some states require doctors or doctor supervised personnel to do it. In other states it can be delegated to other licensed professionals such as nurses, physician assistants, estheticians, or Certified Medical Electrologists.
Types of Lasers
Laser of different wavelengths have been used for hair removal, from visible light to near-infrared radiation. Lasers are typically described by their wavelength, measured in nanometers(nm).
The effectiveness is determined by the wave length, power, and duration of the pulse. The length of the heating pulse is directly related to the destruction of the hair follicle. The laser light waves are absorbed by the melanin in the hair and this heat is transferred to the germ, or stem cells, that are responsible for generating new hair growth. As long as the laser device, no matter what kind, can maintain sufficient temperature for sufficient time the target cells will be destroyed.
The spot size, or the width of the laser beam, directly affects the depth of penetration of the light energy due to scattering effects in the dermal layer. Modern lasers have technology called linear scanning that allows a larger spot size that can reach deeper follicles at higher temperatures. Current lasers have a spot size around the size of a fingertip.
Modern lasers such as the Candela Gentle Max allows the technician to adjust the energy level, or joules per square centimeter (J/cm2). It’s important that the technician set the energy level high enough to heat up and destroy the follicles but not too high to cause unnecessary pain.
Most modern lasers have handpieces with technology built in to minimize pain during the treatment. These can include circulating water through the handpiece, or a cryogen freezing gas spray that activates before or after each laser pulse.
Hair grows in three phases called anagen, catagen, and telogen. Only actively growing hair in the Anagen phase is susceptible to the damaging effects of the laser pulses. This is why multiple sessions are required for effective removal.
Different hair and skin types may require different phasing between treatments, but sessions are typically spaced between three and six weeks. Most body parts are effectively treated in 6 or 7 sessions; however, men’s facial hair may require more treatments.
Laser Hair removal doesn’t work well on light colored hair, red hair, as well as very fine vellus hair. Patients with black skin and black hair can be effectively treated with a long-pulsed Nd:YAG laser with a cooling tip. Don’t try to treat this skin type without the proper equipment and a professionally trained physician or severe skin damage can result.
After each treatment the hair follicles will fall out by themselves over two to three weeks period. Patients should not try to manipulate the hairs. Exfoliation of the skin several days after treatment is sometimes recommended.
Some temporary side effects are normal post treatment. These include some itching, pink skin, redness, and swelling around the follicles (follicular edema). These side effects rarely last more than a few days. The two most common longer-term side effects are acne and skin discoloration. Both are temporary and will go away over one to six months.
Some level of pain should be expected during treatment. Few people experience enough pain to require a numbing cream, but they are available. They should be applied 30 minutes before treatment. Icing the treatment area post-treatment can also help. The best advice is to go to a facility that has modern equipment that uses cryogen freezing sprays that pulse along with the laser pulses. This cools the skin and eliminates much of the pain.