IPL (Intense Pulsed Light) is a broad-based light which is different from a laser in that it has multiple wavelengths instead of one single wavelength of light. This means it targets many different things. Usually IPL devices have filters which can narrow the band of wavelengths that are being used to make the device more specific. In general IPLs have wavelengths which target melanin, and these wavelengths are what target the melanin in the hair shaft and the hair follicle to injure and destroy the hair.
Better on Dark Hair, Light Skin Tones
Typically IPLs will work better for hair removal on lighter skin with darker hair as the wavelengths target pigment to reduce hair and if the skin is dark and the hair is also dark, the light will have trouble differentiating which to target.
IPL vs. Laser
There have been studies which show that these IPL devices may work as well for reduction of hair as lasers, but I think the success of IPL for hair really depends on which specific device is used, what settings are used, and the experience of the user. Again, you have to be careful of using these devices in patients with darker skin or who are tan, as IPLs have a broader wavelength range. There are several devices that employ bipolar radiofrequency in association with intense pulse light, however I haven’t seen any studies that show that that’s any more effective than the intense pulse light by itself.