Which Laser?

In hair removal applications only four medical laser types are used with any success. The Ruby laser, working at a wavelength of about 700nm ( nanometers), is a red light and was the first and is the still very effective. It has the disadvantage of being a very inefficient laser requiring a huge amount of input power for a useful output; it is also not good for darker skin types. The Alexandrite laser operates at about 750nm which is just in the infrared spectrum, it can be effective but both these machines usually suffer from insufficient power for the fairer skin types. The YAG laser operates at about 1000nm and if you look on the following graph you will see that this is in a part of the spectrum where water starts to absorb light and where melanin absorbs it poorly. This is all bad. The melanin does not get as hot as it should and other cells in the epidermis which we want to protect from heat get too hot because they contains over 70% water. These are not widely recommend laser types for hair removal.

Intense Pulsed Light systems, mistakenly and commonly referred to as lasers by a majority of service providers here in Ontario, use a flash lamp as their source of light. This light is of all visible and many invisible wavelengths. These machines find it hard to get enough light at the right wavelength to the hair follicle.

The following is an absorption curve graph for the important molecules in the physics of hair removal. Note that the Ruby, alexandrite and diode lasers all have good melanin absorption rates, but poor absorption by both water and the haemoglobin in blood. Following the graph is tissue penetration chart showing the depth of penetration of the various types of lasers available in the market today. Note that the Diode laser, as the ones used at Hairaway Canada at their hair removal clinic in Markham has the greatest tissue penetration.

There are systems around where the chromophore is applied in the form of a gel; these gels are either black from the carbon content or green using another chromophore. They do not work. Only systems where the melanin in the hair is itself the chromophore work. Yet other systems require that the hair is waxed first. This offends the basic physics - they do not work. The service providers would have you believe that the chromophore penetrates the hair follicle from which the hair has been removed. This would be good, because it would not matter what colour the hair was. Unfortunately no one has worked out how to get a useful amount of the chromophore substance into the follicle.

The medical lasers which can actually produce the results desired by those seeking hair removal are those used at Hairaway Canada at its medical laser hair removal clinic in Markham.