The Anatomy of Hair and why more than one treatment is necessary. Hairaway Canada provides some answers.

There are one or two important things you should know on the microscopic level.

Hair grows rather like the dead corneal layer of the skin: cells flatten and keratinise which as defined by the dictionary means to undergo a type of change.  Nails grow in a similar way.

A germinal layer in the proliferative zone of the bulb continuously produces cells. Melanin is produced by melanocytes in the bulb, the cells keratinise ( undergo a change), include the melanin and form the shaft of the hair.

The hair goes through a growth phase called ANAGEN and whilst in this phase continues to grow longer, then stops growing and starts to shrink away from the proliferative area of the bulb. This is called CATAGEN. The hair then enters the final phase during which it falls out: this is TELOGEN.

It is only when the hair is in anagen that there is good physical proximity between the hair and its germinal cells. These germinal cells have to be destroyed for the follicle to cease producing hair. For these reasons, hair must be in the active growth phase or anagen for the medical laser treatment offered by Hairaway Canada at its clinic in Unionville, Markham to be successful. Only a proportion of hairs are in the stage of growth at any one time. For this reason more than one treatment is required for a good percentage of the hairs to be permanently removed.

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.

Factors affecting successful Hair Removal.

1. POWER: First sufficient power must be applied, enough in fact to heat the core temperature of the hair sufficient enough to carbonise the hair producing cast. This can only be achieved by medical lasers for hair removal. Intense Pulsed Lights commonly used at beauty salons and non specialist centres cannot generate the necessary power levels.

2.WAVELENGHT OF LIGHT: At 800nm the light penetrates the skin well to reach deep follicles, better than Alexandrite or Ruby Lasers and far more effective than IPL systems. This is because shorter wavelengths are more easily reflected around by the superficial skin structures than the longer wavelengths of the medical lasers used at Hairaway Canada.

3. COLOR OF HAIR AND SKIN: The hair MUST be pigmented ( ie have colour, like be black, dark brown, brown and in some instances light brown as well.) The less pigment, the more power will be required but high powers can only be applied to very fair skin.  Very fair hairs are untreatable for permanent hair removal.  From the Fitzpatrick Classification of Skin types chart, we are able to provide effective treatment to Types 1 through Type 5. Type 6, i.e. those with black skin are not treatable.

4. DIAMETER OF HAIR: Hair has a low specific heat, this means that a relatively small power input will result in high hair shaft temperatures but it also means that its ability to store heat is small. The thicker the hair the greater storage capacity from which to spread the heat to neighbouring structures. This means that very fine hair needs to be heated to higher temperature than coarse hair.

5. GROWTH CYCLES: Please refer to our previous blog on growth cycles. Hair which spends a high percentage of its time in Anagen always treats better because hair in Telogen does not treat.

6. DEPTH OF THE BULB: The bulb area of the follicle can be several mm deep. The medical laser used at Hairaway Canada, because of its long wavelength is not reflected to the same extent by the various dermal and epidermal structures, thus allowing more photons to impact with deeper hairs which are also usually coarser hairs.

7. PULSE WIDTH: Each spot delivered with the medical laser used at Hairaway Canada consists of a pulse which can be varied so that all its energy can be delivered in a shorter time or alternatively spreads it out so that the energy is never so high but lasts longer. Both have the same heating ability but the hair does not become so hot in the second and the heat spreads to the surrounding structures for longer.

8. THERMAL RELAXATION TIME: The advanced medical lasers we use at Hairaway have two settings. Where the time the energy is applied is automatically set and the other where the time is fixed.

9. BONE EFFECTS: The epithelium is subjected to both the primary light generated and a secondary pulse which is reflected on the bone. Our experience, having successfully performed over 60,000  procedures enables to ensure that when treating boney prominences, our treatment parameters are adjusted accordingly to ensure absolute best possible outcomes.

10. SUNTANS: We do not offer treatment to clients whom have sun tans. First they cause the skin to be darker, so putting it into a higher skin category than necessary but more importantly colour from tanning poses a larger problem which means we would be obliged to reduce the power levels resulting in a poor treatment with no out come.

11. GENETIC FACTORS: If it were a simple matter on analysing the skin colour and then applying the appropriate energy level, we could have colorimeter do the job and do the job as the machine advises. This is what commonly happens at Beauty Salons and non specialists centres. They rely on the machine to advise them!  Unfortunately things are not easy and requires service providers with a deep understanding of all the factors that can affect the outcome of a treatment. Thankfully, Hairaway Canada has the necessary experience and skill sets to assess each client carefully and proceed accordingly.

The Principles Behind our Hair Removal technique

Selective Photothermolysis is the name given to a process in which the hair is selectively heated to a much higher temperature than the skin through the action of light.

Melanin, the chromophore which colours the hair and which is also present in the inner and outer sheath, absorbs light from the laser, becomes hot and passes this heat on to the hair itself. The proliferative region of the hair follicle responsible for the actively growing hair is then heated because of its proximity to the hair shaft. If these cells are heated to a temperature greater than 65 degrees, the protein making up the cells will coagulate and these cells will die.

The death of these actively dividing cells of the hair bulb section of the hair follicle results in an inactive follicle no longer capable of producing hair. Death of a proportion of the cells only, results in the miniaturisation of the follicle with the result that the hair will grow finer on return. Death of some of the melanocytes, the cells that five colour to the hair, will result in a fairer hair returning.

So from this you will see that the degree to which the hair is heated is absolutely critical to the achieving a permanent result of the treatment. Too low a fluence ( the energy setting on the device) will result in insufficient heat to kill the cells responsible for hair growth. This is most often the outcome of the treatment with devices such as pulsed light systems used at beauty salons and non specialist centres. Too much energy and the skin pigment ( also melanin) will absorb sufficient light to heat the germinal cells of the epidermis resulting in an aggressive response.

We have successfully performed over 60,000 procedures and are eminently qualified to produce results which are permanent at our hair removal clinic in Markham. Our medical lasers are the most advanced systems in the market for hair removal and you can rest assured that they generate the appropriate  amount of energy to generate the heat required to cause the coagulation of the cells.