Laser hair removal

Also known as: LHR, alexandrite laser hair removal, diode laser hair removal, Nd:YAG hair removal

Laser hair removal targets melanin in the hair follicle with pulses of laser light, and it is one of the best-evidenced cosmetic procedures: controlled trials and meta-analyses consistently show 50 to 85 percent long-term hair reduction after a series of treatments. The key honest correction to marketing is the word removal: the evidence supports lasting partial reduction, not guaranteed permanent elimination of all hair, and results depend heavily on hair color (dark hair responds, white and blonde hair barely does).

How it works

Melanin in the hair shaft absorbs the laser pulse (755 nm alexandrite, 810 nm diode, or 1064 nm Nd:YAG) and converts it to heat, damaging the follicle's growth structures. Only follicles in the active growth phase are vulnerable, which is why 4 to 8 sessions spaced weeks apart are needed to catch each hair cycle. The 1064 nm wavelength penetrates deeper past epidermal melanin, making it the safe choice for darker skin.

What the evidence says, claim by claim

These are the results measured in studies, not the results shown in ads. Where the research is weak, the grade says so.

For long-term hair reduction

Strong evidence

An evidence-based review found the best trial support for alexandrite (3 RCTs, 8 controlled trials) and diode (3 RCTs, 4 controlled trials) lasers, with repeated treatments giving partial hair reduction persisting beyond 6 months. A meta-analysis of hair removal laser trials reported roughly 55 to 58 percent reduction at 6 months after about three sessions, and comparative trials report around 84 to 85 percent reduction at 12 months after four sessions with alexandrite or diode devices.

Multiple randomized controlled trials or a meta-analysis support this use. The effect is real and repeatable.

Evidence-based review of hair removal using lasers and light sources (Journal of the European Academy of Dermatology and Venereology, 2006; systematic-review)
Meta-analysis of hair removal laser trials (Lasers in Medical Science, 2009; meta-analysis)

For permanent complete hair removal

Not enough evidence

The claim that laser leaves you permanently and completely hair-free is not what the trials show. The evidence-based review found no controlled evidence of complete and persistent hair removal; what is documented is partial long-term reduction, with regrown hair often finer and lighter. Hormonal conditions, light-colored hair, and stopping short of a full course all reduce results, and many people need maintenance sessions every 6 to 12 months.

The marketing has moved faster than the research. There is no good human data behind this use yet.

Evidence-based review of hair removal using lasers and light sources (Journal of the European Academy of Dermatology and Venereology, 2006; systematic-review)

For hair removal in darker skin

Moderate evidence

Long-pulsed 1064 nm Nd:YAG is the documented safe and effective option for Fitzpatrick IV to VI: in a study of darker-skinned patients, 86 percent had no complications and all complications were transient, with hyperpigmentation the most frequent. Efficacy per session tends to be somewhat lower than alexandrite in light skin, so more sessions may be needed, but meaningful long-term reduction is well supported.

Randomized trials support this use, but they are few, small, or short. The effect is probably real. The size of it is less certain.

Long-pulsed Nd:YAG laser-assisted hair removal in Fitzpatrick skin types IV-VI (Lasers in Medical Science, 2011; clinical-trial)

Risks and what can go wrong

Essentially no downtime; expect transient redness and perifollicular swelling for hours to a day. Risks include blistering, crusting, and pigment changes, mostly when the wrong wavelength or settings are used on tanned or darker skin; paradoxical hypertrichosis (increased fine hair growth, most reported on the face in some skin types) is an uncommon but documented effect. Avoid treating over tattoos, with a fresh tan, or on photosensitizing medication. Eye protection is mandatory, and periocular treatment requires specific precautions.

The practical details

Typically 6 to 8 sessions spaced 4 to 8 weeks apart depending on body area, then occasional maintenance. US pricing runs roughly 100 to 400 dollars per session per area (underarms at the low end, back or legs higher). In-office or medical spa; home IPL and diode devices produce smaller, slower reductions at much lower energies.