The Pulsar is a Intense Pulsed Light (IPL) device, and as such, it releases precise, controlled pulses of filtered light at specific wavelengths which are absorbed by the melanin in the hair root follicles. White, grey, very light blonde or red hair often do not sufficiently contain the melanin required to get rid of them in their roots. The Pulsar does, however, work for the vast majority (~99%) of other hair colors. Even for very blonde individuals, but nevertheless have hair that have some pigment, the Pulsar often can be used but in such borderline cases, it is recommended that they first consult a dermatologist or other certifical medical professional.