Premise

• Hair removal lasers use a wavelength of light that is tuned for the individual's skin pigment and hair color to affect only the dark melanin compounds in hair. When these compounds have been boiled away, the hair follicle dies and falls out.
  
  

Skin Discoloration

• Since lasers indiscriminately target the melanin they are tuned to destroy, they can destroy pigments in the skin as well as the hair if the two are too close in color.
  
  

Skin Color

• Dark hair and fair skin are the best-case scenario for laser hair removal, since the wavelengths are so far apart. It is for this reason that specialized YAG lasers were developed, as their tuned wavelength can be used on all colors of skin.
  
  

Temperature

• Localized temperatures of laser hair removal regularly exceed the boiling point of water in the follicle, but dissipate quickly enough that the laser usually causes little or no damage to the surrounding tissue.
  
  

Cooling

• Many laser hair removers uses a compressed cryogenic gas system to cool the scalp in between laser pulses, and others use a clear gel to absorb the heat.