For brown spots on the legs, what is the most effective laser??
Okay, so I’m thinking you meant IPL instead of IPD. IPL lasers can be quite effective for flat (not raised) brown spots (lentigoes) on the face and works quite well on the chest. As you move down the body, it works less well.
On the legs, the Fraxel Dual is much more effective but also requires more skill. Make sure of the quality of the center you pick – you want a board certified dermatologist or plastic surgeon on site full time with a lot of expertise and experience with lasers.
More information on how to find a good dermatologist.