These methods are unpleasant and give temporary results. Most methods have various unpleasant side effects such as pigmentation development, most commonly on the upper lip and ingrowth of hair which causes scars.
Everything about hair
A hair develops from special stem cells which are located in the hair root. Just by destroying stem cells in the hair root we can prevent their growth. There are two hair types: vellus and terminal hair. Vellus is the thin, gentle light blond hair with which we are born. Out total number of hair is determined by birth and cannot be amplified. Hair which grows after a removal treatment is immature hair which matures in time (this is not new hair). Shaving does not increase the total number of hair but strengthens the existing root and speeds up their maturing process.
During time and due to hormones and other factors a vellus hair matures into a terminal hair which is darker and thicker. Hair color depends on the quantity of pigment melanin, which is the main target of laser hair removal or an IPL treatment. There are two types of pigment which give hair its color: eumelanin and pheomelanin. If there is more pheomelanin, as is with light blond and red hair, the removal result is poor because that pigment type absorbs the laser ray poorly. If there is more eumelanin, the result will be excellent because that type of pigment absorbs the laser energy very well.
The amount of one's hair depends on numerous factors: race, genetics, age, climate, skin color... For Mediterranean climate, thicker black hair is usual, while in more northern parts hair is lighter and gentler. In many families the amount of hair is plentiful, especially with women of darker complexion, and the cause are not hormonal disorders.
Hair growth phases
Hair has three growth phases: the anagen, catagen and telogen phase. Hair travels and matures independently, each with their own different speed towards the skin surface. Only during pregnancy all hair is in the same growth phase and that is why at that time it is the thickest, but soon after birth things are restored as they were before the pregnancy.
- In the anagen phase the hair grows, and only in this phase can it be destroyed because there is enough pigment to destroy the root. Pigment absorbs optical energy from the laser or IPL rays and the more pigment there is more energy, which destroys stem cells, is absorbed. Light and gray hair do not have pigment and therefor cannot be destroyed. In other phases there is not enough pigment and subsequently the hair root cannot be destroyed. The length of the anagen phase varies depending on the location and number of hair which are in that phase. For that reason the interval between the treatments and success in hair removal varies depending on treatment areas. Only by shaving can we increase the number of hair in the anagen phase.
- The catagen phase is the moment when hair start to whither. The quantity of pigment decreases and stem cells stop producing hair. The initial separation of hair from the root begins and hair travels towards the skin surface.
- The telogen phase is the final phase of hair growth where an old hair is being ejected and the cycle begins anew. In this phase the hair is completely removed from the root and there is a minimal quantity of pigment.
On what does success depend on?
- The number of hair in the anagen phase is the most important factor which determines success. Other factors exist, for example and ideal patient isn't the one with light complexion and thick black hair. Oftentimes people with a darker complexion have better results. A 65ºC temperature is not necessary to destroy the hair root, as was considered until now. With development of technologies rules change and treatment results improve.
- Treatment area. It is a paradox that 70% of chin hair are in the anagen phase while only 20% of leg hair is in that needed phase but still results are better. For facial, chest and back hair more treatments are needed.
- Number of hair and pigment type. A precondition for a good result is a larger number of eumelanin in regard to pheomelanin. If you can smell burned hair during the treatment, it is a sign of success.
- Depth of the root, which varies with the body area. It is deepest on one's neck, back, armpits and bikini zone where it can be up to 5mm deep. Penetration depth of the laser and the IPL device depends on the wave length. The bigger the wave length the deeper the penetration. Neodymium Yag laser has the biggest wave length of 1064nm and penetrates the most.
- The laser beam ratio or the IPL extension surface also determine the penetration depth. The larger the ratio of the laser beam or the IPL extension surface the deeper the penetration. With the development of newest technologies these rules do not apply completely.
- One of the most important success factors on which hair removal depends on is the number of androgynous receptors, i.e. areas of male hormone activity. Receptors are areas where male hormones are linked and under their influence immature vellus hair becomes mature. The number of receptors is largest in the area of the upper lip and chin, and smallest in legs, bikini zone and on the back. The largest number of vellus hair is on one's face, chest and back.
- With hormonal disorders of the adrenal gland, due to a hormonal dis-balance, the number of treatments needed is greater. Usually this is the case wit polycystic ovaries.
- On energy and the length of the laser or IPL impulse. The greater the energy the better the result. The type of the device and knowledge of the operator is also important.
What is better for hair removal, lasers or an IPL device?
Bigger difference didn't exist until recently, but now we can say that according to the newest research lasers give better results. Also they have a couple of advantages such as a shorter treatment time, and they are significantly safer in comparison to IPL devices.