Intense Pulsed Light targets the colour pigment (melanin) in the hairs. Therefore white hairs can not be treated. Dark hairs on fair skin have the best and quickest results. Fair hairs will require extra treatments with lesser results. Caution is required when treating hairs on darker skins; this is explained below and would be discussed more fully during your consultation.
The hair growth cycle:
Hairs grow in constant cycles: Firstly hairs are actively growing, then they become dormant (resting), and finally they loosen and shed, only to be replaced by more new, actively growing hairs.
Only hair follicles in the active growth stage are disabled by IPL treatments.
Hairs in the dormant stage of the growth cycle normally remain anchored in the follicles for weeks or months, depending on their location, but their follicles and associated hair germination cells are not disabled by IPL treatments. These follicles will be treated in subsequent sessions. This is why you need repeated sessions. Hair growth becomes sparser with each session. All treated hairs should shed within about two weeks.