Laser Hair Removal: Which setting is right for u?

Your feedback or opinion regarding my point of view below is welcome.

First of all I don’t believe in pain-free laser hair removal or no down-time because it indicates under-treatment.

How to make Laser Hair Removal (LHR) the most effective?

All of the following conditions must STRICTLY be achieved in order to obtain efficacy and the optimum successful results from Laser Hair Removal (LHR):

I. End Points which determine the success of each treatment
What should be observed as indicators for the successful treatments?
– Erythema (redness) - Redness around the treated hair follicles is a good clinical endpoint
– Perifollicular edema (swelling) - Swelling around the treated hair follicles is the best indicator that the correct fluence has been used.
– Hair vaporisation - The smell of burnt hair or hair popping out the follicle is a very good indicator that the treatment is working.

II. Your hair must be at the anagen phase
The most effective result is when hairs are in the active cycle (or anagen phase). 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.

Why only anagen hair?
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 surrounding that has no dark pigment. Any colourless, red, blond, grey & white objects don’t absorb light produced by the current LHR & IPL devices.
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.

III. Avoid under-treatment of both LHR and IPL &
IV. Avoid both LHR and IPL treatments when majority of hairs are not in anagen
These can bring about many repercussions. For examples:
– Under-treatment can cause increased hair growth by turning fine, vellus hairs into terminal ones.
– Both III & IV can significantly undermine the efficacy of LHR in the long run and the clients may lose the chance to have a successful result of PERMANENT hair reduction forever 😭. Why? Every time you received treatment dark pigments (AKA melanin) & dark-colour hairs are destroyed & weaken. LHR is most effective on dense, thick, coarse & dark hair because they have a lot of pigment and can absorb a lot of heat. Sparse, fine hairs cannot absorb much heat. Thus, LHR lose efficacy on sparse or thin hairs.

Reference: https://aestheticlasertraining.co.uk/courses/vtct-fast-track/lectures/ and etc.

The photos look like effective successful laser treatment to me (but it’ll just be better to lower the fluence by around 2 j/cm^2. If no redness & swelling around hair follicles, this indicates under-treatment. These photos are definitely not burn. The client will get a good result after this.

What I tried to say above is that the settings of parameters (namely, Wavelength in nm, Fluence in J/cm^2, repetition of pulses in Hz & Pulse width in nm) are different among different brands & manufacturers. The right setting is when you see your skin appearing red & swollen around hair follicles few minutes after the firing. As you progress with more sessions later on, Fluence should be increased higher & pulse width should be narrower when hair become thinner.

sorry typo error
Pulse width in ms (milisecond)

Please note that erythema & edema won’t appear as soon as the laser beam/pulses hit you, but few minutes or longer after that => That’s one of the reasons to do the test patching to find the right energy for different individuals.
Make sure you don’t feel the heat (u may still feel warm a second or 2) as soon as the laser pulses moved away from that treated area. The heat should go away as soon as the pulse moved away from that treated spot => Otherwise burn.