Laser Hair Removal (LHR)
Not all current IPL & laser devices work effectively and are suitable to remove hairs. Hair can be permanently reduced/retarded only when the appropriate wavelengths of light are used for the sufficient period of time so that the sufficient light is absorbed by dark colours and converted to heat sufficiently enough to destroy hair FOLLICLES while minimal energy is transferred to the surrounding skin. If this can occur then there is high possibility that hair may reduce/remove permanently. There are things to consider, principally:
– Wavelengths (nm)
IPLs are made to produce a band of spreading & incoherent wavelengths, whereas lasers are made to produce a specific single wavelength of light which have more concentrated energy. Thus, laser is more specific to a given target than IPL, and therefore laser is more effective than IPL in removing hair and laser has fewer side effects and complications than IPL.
The laser wavelength for deep, thick, coarse & dark hair underneath the skin should be 1064nm (Nd:YAG). The lasers with wavelength of 755 nm (Alexandrite) or 800-900 nm (Diode) work effectively with shallower, thinner & lighter hair. If your hair root deeply, energy from lasers with shorter wavelengths won’t reach the bottom of your hair bulb & follicle.
Based on many manipulated scientific studies, 755-nm and diode lasers are more efficacious in hair removal than Nd:YAG.
– Skin colours
1064nm is suitable for all skin types but less efficacy. 755nm is safe to be used for Fitzpatrick Skin Type 1, 2 & 3 only. Diode is safe to be used for Fitzpatrick Skin Type 1, 2, 3 & 4 only.
Very dark-skinned individuals need to have a laser with a longer wavelength. The longer wavelength is needed so as not to have the laser energy preferentially absorbed by the top layer of skin as would occur with the shorter wavelength laser. The longer wavelength penetrates deeper and will target the deeper dark pigment decreasing the risk of blisters or burns on the surface.
– Pulse Duration or Pulse Width
means how long each laser beam is allowed to work on you. The longer pulse duration is for the thicker hair diameter. Longer pulse shouldn’t be used for thinner hairs to prevent damage to adjacent tissue.
Laser devices operate as continuous wave or pulsed systems (e.g. single or repetitive pulsed). Examples of multi-pulsed (aka, repetitive-pulsed) laser devices are Short Pulsed, Long Pulsed and Q-switched for different treatment purposes. But long-pulsed lasers in 755, 800-900 & 1064 nm have proved to be effective in reducing hairs permanently.
Q-switched & other short-pulsed lasers which emit laser beam in much shorter duration of time won’t do anything to your hairs except bleaching hair colours. Both the amount, density & size of your hairs will remain exactly the same. Remember! Once hair get bleached, IPL & Laser won’t be effective for lighter hairs. 
In other words, if the pulse duration is too short or too long this can result in unanticipated side effects.
– Fluence, Spot Size & Repetition Rate (Hz)
to be applied are according to different recommendations among different brands. They can be increased or decreased depending on the previous results and clients’ feelings during different treatment sessions.
Fluence (J/cm^2) means energy of each laser beam per 1 square centimetre of treated area. Fluences are not comparable between machines of different brands.
Spot Size (mm) is the size of laser aperture. In general, the smaller the spot size the higher the fluence setting. Vice versa, the bigger the spot size the fluence must be set lower.
Repetition Rate (Hz) is the number of laser pulses per 1 second.
Pulse Duration/Width for Laser Hair Removal devices are in millisecond (ms) - Since fluences are not comparable between machines of different brands, some brands require only 3-20ms. Some other brands require 60-80ms for lower fluence to work longer.
Aim is to raise the temperature to fully coagulate the hair FOLLICLES and that temperature is above 70°C. So how can the clients feel painless if the treatment is meant for efficacy?
Rule of thumb: The effective settings are when treated hair follicles appear red & swollen few minutes after the firing.
Please note that erythema (redness) & perifollicular edema (swelling) won’t appear as soon as the laser beam/pulses hit you, so do the over-treated signs of blistering or burning, but few minutes or longer after that. That’s one of the reasons to do the test patching to find the proper energy settings for different individuals & for different body areas.
– Depth of Penetration
is dependent upon the wavelength, fluence, and the spot size.
In general, the longer the wavelength the deeper the penetration into skin. The bigger the spot size the deeper the penetration into the skin. The setting must match the depth of the target to be destroyed. If the setting is for deeper penetration, this won’t be so effective for the target locating shallower.
Settings of different parameters can be increased or decreased depending on the previous results and clients’ feelings during different sessions.
The right setting is when you see your skin appearing red & swollen around treated hair follicles few minutes after the firing/laser pulses. As you progress with more sessions later on, either Fluence, Hz or both should be increased higher & pulse width should be narrower when hair become thinner.
///////////// The efficacy of LHR significantly depends on: /////////////////////
– The colours of hair underneath the skin
Current IPL & laser is ineffective for blond, red, grey and white hair, but it is effective for natural brown & black hairs.
– Density & diameter of DARK hair underneath the skin
The treatments are more effective on dense, thick, coarse & dark hair because they have more pigment that can absorb more light. The higher density of dark hair the better result. Either sparse or fine hairs cannot absorb enough light to destroy the follicles. Thus, LHR lose efficacy on either scattered hair or very thin, vellus hair.
– The colour of the skin vs. the colours of hair underneath the skin
If the surrounding skin is lighter than the colour of the hair, the energy of the laser is concentrated mainly in the hair shaft, effectively destroying it without much affecting the skin.
If the skin contains dark melanin, melanin in both skin & hair will absorb laser light, thus less heat concentration in the hair.
The less pigment in the skin and the more darker pigment in the hair, the better result.
The darker the skin colour the higher risk of skin damage or burning, thus the lower the energy of laser setting and the less efficient of laser treatment.
– Hairs of different areas & hormones
Results also vary among different areas.
Areas that aren’t controlled by hormones, such as lower arms & lower legs, usually respond well to LHR.Â
There have been cases LHR can stimulate hair of areas that are controlled by hormones, such as face, upper arms, chest, abdomen, back & inner thighs, by turning fine, vellus hairs into coarse, terminal ones. Some individuals can end up look harrier in some areas after LHR. However, results vary among different individuals & different areas can have different results.
– Phase of the hair growth cycle
The most effective result is when hairs are in the anagen phase. Why?
Any dark-colour objects (in this case, skin & hairs of all growth cycle including anagen) absorb light from laser and turn the light into heat and give off such heat to surroundings that have no dark pigments.
Only hairs in anagen phase are still in contact with the parts of colourless hair follicles containing colourless stem cells. Even though hairs in other growth phases absorb light from laser and give off heat to surrounding but they have lost contact with stem cells. If the stem cells aren’t destructed, hairs will eventually grow back.
At any given time, not all hairs are in anagen phase. Therefore, multiple treatments are required to achieve the optimal appearance.
Timing between treatments is very important for optimal results with LHR. Different body areas have different hair growth cycles. In order to catch the most hair in the anagen phase during your LHR sessions, as soon as a significant percentage of the hair starts emerging out of your skin, return for the next treatment. Typically 4-6 sessions are recommended, which are done at 4-6 week intervals to catch each cycle of hair growth. Some people may be satisfied with their results sooner. Some may require more sessions. Results vary among different individuals.
Following these guidelines should result in the greatest reduction of hair.
Once desired results are achieved, many people still require maintenance sessions around few treatment sessions annually. While in the maintenance phase, the ideal time to get a touch-up session is when you notice there are times when hair growth seems to be more aggressive. This is, as hair in the anagen phase, most effectively targeted.
Unfortunately, laser & IPL can only reduce hair. After prolonged dormancy, unwanted hairs can regrow even many years after successful LHR. If u want to have every single unwanted hair gone forever, Electrolysis is the only solution.
