Hair removal · Practical guide · Phototypes I to IV
The Alexandrite laser, built into our Clarity II device, is used at Photoderma for permanent hair removal on the fair skin of Fitzpatrick phototypes I to IV. Its short wavelength, 755 nm, concentrates heat inside the hair follicle without raising skin temperature. Plan on roughly eight sessions for a lasting result.
Detail · Ideal candidate · Skin + hair
For fair skin carrying dark hair. The Alexandrite is drawn to melanin: it must distinguish the color of the hair from that of the skin. Phototypes I to IV offer that contrast and are the safe operating zone on the Fitzpatrick scale.
Eligible hair color
Safety guardrail. The Alexandrite must be used on dark hair with fair skin. Without this color contrast, the laser can no longer distinguish the hair from the epidermis and causes a cutaneous burn. Phototype assessment is done in clinic before the first pulse.
Detail · Mechanism · Short wavelength
With its very short wavelength, 755 nm, the Alexandrite is strongly absorbed by the melanin of dark hair. It distributes its heat only inside the hair follicle and destroys the root (bulb), without raising the skin temperature of fair phototypes.
The beam is delivered by the Clarity II handpiece and crosses the fair epidermis without leaving most of its energy there.
The melanin of the dark hair captures the short wavelength: it is the hair, not the skin, that concentrates the heat of the pulse.
The heat travels down the shaft toward the root. Energy is deposited in the bulb, where the hair is produced, causing its destruction.
The jet of cryogen fired before each pulse freezes the surface. Combined with the short wavelength, it keeps skin temperature stable on fair skin.
Detail · Protocol · Duration per zone + cadence
Firing speed is one of the strengths of the Clarity II. Underarms are treated in just 5 minutes, the full bikini in 15 minutes, and the back in 25 minutes. In total, plan on about 8 sessions spaced 4 to 6 weeks apart for the face and 6 to 8 weeks apart for the body.
Durations drawn from the device sheet; the operator adjusts cadence depending on hair density and fineness.
In total · full series
≈ 8sessions for lasting hair removal
Treatments are spaced out over time to catch each hair as it enters the anagen phase. Outside of that window, the follicle does not receive enough energy.
The audible sound during the session comes from the cryogen propelled onto the skin before each pulse, not from the power of the laser.
Detail · Limits · What the Alexandrite does not treat
A laser reads light. It needs pigment present in the hair and contrast with the skin. In four specific cases, that reading is not possible and another route is required.
01 · Phototype
Cutaneous melanin itself absorbs the 755 nm beam. The laser can no longer distinguish the hair from the skin and causes an epidermal burn. We switch to the Nd:YAG laser, whose target is the hemoglobin of the nourishing vessel.
02 · Pigment
The melanin concentration is insufficient: the laser cannot "see" the hair. We leave this purpose to electrolysis, which acts by electric current, hair by hair, without depending on pigment.
03 · Tan
A recent tan temporarily increases superficial melanin and creates a risk of confusion with the hair. The evaluation postpones the session or proposes an alternative to avoid a cutaneous burn.
Session postponement recommended until the usual phototype returns.
04 · Fine hair
Some areas only carry vellus hair (cheekbones, earlobe, upper fair arm). The Alexandrite laser is not suited to them. Electrolysis or a non-laser solution can be offered instead.
Personalized evaluation during consultation.
Navigation · Other hair removal paths
The source sheet points to two other hair removal paths. Each has its specific indication, and we can combine them in a single protocol if your skin and hair require it.
Laser 2 · 1064 nm
For phototypes V and VI, meaning dark, olive, and mixed-tone skin. The Nd:YAG reads the hemoglobin of the blood vessel at the root of the hair, not the melanin of the skin. The epidermis remains intact.
Current-based method · since 1916
For hairs that light cannot read — white, blond, red, or vellus. Electrolysis acts by electric current, hair by hair, without depending on pigment. It often complements a series of Alexandrite laser.
Before your evaluation
Because 755 nm is a short wavelength with very high affinity for the melanin of dark hair. It releases all of its heat into the follicle and avoids raising skin temperature, which gives an ideal energy-to-pigment ratio for the fair skin of Fitzpatrick phototypes I to IV.
No. Vellus hairs, white hairs, and blond hairs cannot be removed with a laser because their melanin concentration is insufficient to absorb the beam. For those hairs, electrolysis by electric current remains the proven method, hair by hair, without depending on pigment.
Plan on roughly eight sessions in total to permanently remove the hair, with each pass of the full bikini lasting about 15 minutes. Sessions are spaced 6 to 8 weeks apart on the body in order to respect the hair growth cycle and target follicles in the anagen phase.
The Alexandrite laser is the reference for Fitzpatrick phototypes I to IV, meaning very fair to light-olive skin. Beyond that, cutaneous melanin would absorb the beam. We evaluate your phototype in clinic before the first session and recommend the Nd:YAG if you are phototype V or VI.
An in-clinic evaluation precedes every series. A recent tan increases superficial melanin and the risk of confusion between hair and skin. We recommend waiting for the tan to fade and confirming your phototype before the first pulse to avoid a cutaneous burn.
Next step · Confirm your phototype
Before the first pulse, the in-clinic evaluation checks three things: your Fitzpatrick phototype, the color and density of the target hair, and the area to be treated. In case of incompatibility, alternating with the Nd:YAG or an electrolysis component may be recommended. Medicard financing over 6 or 12 months with no initial fee applies to the full course.
The consultation is brief and non-binding. It prevents unnecessary sessions and secures the full series.