The reason is the hair cycle
The laser destroys the follicle only when the hair is in active growth (anagen), because that is the only phase in which the hair is still firmly attached to the structure that must be damaged.
And here is the number that explains everything: in any body area, only 20% to 30% of follicles are in anagen at once. The rest are dormant, and the laser passes over them without touching them.
Hence the sessions: each one reaches only the fraction that is awake that day. And hence, too, why 100% is physically unreachable with this method.
So what result can you actually expect?
After a full plan of 6 to 8 sessions, spaced 4 to 8 weeks apart depending on the area, the usual outcome is a very high, lasting reduction: whatever remains will be finer, lighter and slower, and in many areas essentially imperceptible.
That lasts for years. But the follicles do not vanish from the map: hormonal change, pregnancy, menopause or simply time can reactivate some. So a maintenance session every year or two is normal. It does not mean the treatment failed. It is how it works.
When laser will NOT work (and nobody tells you)
The laser needs pigment in the hair to absorb the energy. Without pigment there is no target.
So white, grey, very light blonde and red hair responds poorly or not at all, however much power is used. It is a physical limitation, not a question of device, technique or brand. Anyone selling you a package for white hair is selling sessions that will not work, and they know it.
And a question almost nobody asks: why is that hair there?
If you are a woman and coarse, dark hair in a male pattern has appeared — chin, sideburns, neck, chest, lower abdomen — especially if it came on quickly or alongside acne, menstrual changes or hair loss, it may be hirsutism: the outward sign of a hormonal problem.
In that case the laser treats the consequence and not the cause. It can do that, and it helps a great deal cosmetically — but if nobody investigates the cause, the hair will keep coming. A beauty centre will sell you the package. A dermatology consultation will ask you why.
What it does solve, and solves well
There is one indication where laser hair removal stops being cosmetic and becomes frankly medical: ingrown hairs and recurrent folliculitis — the shave, ingrow, inflame, shave-again cycle — typically on the neck, beard and groin.
Removing the follicle breaks the cycle. For many patients this is what actually brings them in, and it is one of the best indications for the method. See laser hair removal.
Frequently asked questions
How many sessions are needed?
Usually 6 to 8, spaced 4 to 8 weeks apart depending on the area: the face needs shorter intervals, legs and back longer ones. Afterwards, a maintenance session every year or two is advisable.
Will all my hair be gone?
Not 100%. The realistic outcome is a very high, lasting reduction, with the remaining hair finer, lighter and slower — sometimes essentially imperceptible. That is the goal and it is a good result.
Does it work on darker skin?
Yes, with a diode laser and adjusted settings. What cannot be done is treating tanned skin: if you have been in the sun, the session is postponed, because that is the difference between treating and burning.
Can I wax between sessions?
No. Waxing, plucking and threading pull out the root, which is exactly what the laser needs to find. Between sessions you only shave.
Does it hurt?
It feels like hot rubber bands snapping against the skin, buffered by the cooling tip. It is tolerable and the sessions are quick.
Every case is different. Get your questions answered in a personal consultation.
Book a consultation on WhatsAppEvery figure published on this site is approximate and is not a quote. Any procedure or treatment first requires a private assessment consultation with Dr. Arístides Arellano —$800 MXN, charged separately— and it is at that consultation that the definitive cost of your case is determined.
Educational content; it does not replace a medical consultation. Results may vary from person to person.