Hi AK,
The reason you would not want to use self tanning products before laser hair removal is that it will increase the chances of having an unwanted side effect like blisters or burns.
Self tanning products darken the surface of the skin (as does normal tanning - UV rays). When the surface of the skin darkens, it creates a competing target for the light energy of the laser - with the other competing target being the color in the hair. By darkening the surface of the skin, more laser energy will be absorbed at the skin's surface rather than at the base (bulb) of the hair follicle, which is where we want the light energy to be absorbed to result a good treatment.
When too much light energy is absorbed at the surface of the skin, it creates unwanted heat which can then cause blisters or burns. We suggest that you take your practitioner's advice and give it at least 4 weeks after you have used self tanners before getting laser hair removal. Hope this helps.
