Wavelengths, melanin and why "painless" marketing deserves scepticism — a dermatologist explains the physics in plain language.
Every laser hair removal device works on the same principle: selective photothermolysis. Light of a specific wavelength is absorbed by the melanin in the hair shaft, converts to heat, and disables the follicle — while sparing the surrounding skin.
Why wavelength matters
The art is in the match between wavelength and skin tone. Alexandrite (755 nm) suits lighter skin; Nd:YAG (1064 nm) passes safely through deeper skin tones to reach the follicle. This is why a proper clinic asks about your skin before quoting a package.
What "painless" really means
Heat is the mechanism — so a completely sensation-free treatment is usually an under-powered one. Modern cooling makes sessions very comfortable, but if a clinic promises you will feel nothing at all, ask what energy they are actually delivering.
Done properly, most patients see an 80–90% lasting reduction after 6–8 sessions.