Laser hair removal is one of the most evidence-supported cosmetic treatments available, and one of the most misunderstood. The mechanism is well-understood, the results are predictable, and the marketing terminology ('permanent removal') is accurate when you understand exactly what it means.
Selective photothermolysis
The scientific principle underlying laser hair removal is selective photothermolysis, the use of specific light wavelengths to selectively heat and destroy specific tissue targets without damaging adjacent structures. In hair removal, the target is melanin in the hair follicle; the wavelength is chosen to be preferentially absorbed by melanin, with minimal absorption by water (which would heat all tissue equally) or oxyhaemoglobin (which would target blood vessels).
When the laser pulse is delivered, the melanin in the hair absorbs the energy and converts it to heat. This heat conducts down the hair shaft and into the follicular bulge and matrix, the structures responsible for hair regeneration. If the temperature achieved is sufficient (typically 65–70°C), the follicle is permanently damaged and cannot regenerate the hair. If the temperature is insufficient, the damage is reversible.
The hair cycle: why multiple sessions are essential
Hair follicles cycle through three phases: anagen (active growth, ~2–6 years), catagen (transition, ~2–3 weeks) and telogen (resting, ~3 months). Laser is only effective on follicles in the anagen phase, the growing phase where the hair is actively connected to the follicular matrix and the melanin concentration is highest.
At any given time, approximately 15–20% of follicles in an area are in anagen. A single laser session treats this anagen population effectively; the catagen and telogen follicles are not sufficiently damaged to prevent regrowth. This is why multiple sessions spaced 4–6 weeks apart are necessary, each session treats the cohort of follicles that have entered anagen since the previous session.
After 6–8 sessions, the majority of follicles in the treated area have been treated during their anagen phase and permanently damaged. The result is a 70–90% permanent reduction in hair density, 'permanent reduction' being the accurate regulatory term, as a small proportion of follicles will always regenerate.
Darker skin types: Fitzpatrick IV–VI
The selectivity of laser for melanin presents a challenge for darker skin types: the epidermis also contains melanin, and if the laser parameters are not appropriately adjusted, the epidermal melanin absorbs energy alongside the follicular melanin, causing hyperpigmentation, burns or both.
Safe treatment of darker skin types requires wavelength selection (Nd:YAG 1064nm has a longer pulse duration and lower epidermal melanin absorption than diode 808nm or alexandrite 755nm, making it the preferred wavelength for Fitzpatrick IV–VI), conservative energy settings, effective skin cooling, and patience, more sessions at lower energies are safer and ultimately as effective as fewer aggressive sessions.
All Fitzpatrick skin types from I to VI are treatable at Aesthetics Medispa. The patch test and consultation preceding any first treatment are non-negotiable safety steps, not optional extras.
Preparing for treatment
- Shave the treatment area 12–24 hours before your session, the laser needs melanin in the follicle, not the shaft above the skin surface
- No waxing, epilating or threading for 4 weeks before, these remove the hair root, leaving no target for the laser
- Avoid sun exposure and fake tan for 4 weeks before and after treatment
- Avoid heat (sauna, hot bath, intense exercise) for 24 hours post-treatment
- Apply SPF 50 to treated areas for 4 weeks post-treatment, especially face and décolletage
"Preparation is approximately 50% of the result. Clients who arrive correctly prepared, recently shaved, no tan, no sun exposure, get significantly better outcomes than those who arrive unprepared regardless of the equipment used."
The treatment experience
The sensation of laser hair removal varies by area and skin type but is generally described as a series of quick, warm pulses, less painful than waxing for most clients, more intense over bony areas (upper lip, hairline). Modern devices incorporate continuous skin cooling that significantly reduces discomfort compared to earlier generation equipment. Sessions take 15 minutes (upper lip) to 75 minutes (full legs).
Treatments that work. Results you can see.
Every treatment at Aesthetics Medispa begins with a consultation, understanding your skin, your health and your goals.