If this move is successful, the user loses 1/2 of its maximum HP, rounded up, unless the user has the Magic Guard Ability.
This works the same way as Mind Blown. Its self damage is not classified as recoil. :P
Magic Guard does protect against it because it ignores all non-direct damage except stuff like Destiny Bond, Perish Song, and Pain Split. :P
Source, EXP
Hope I helped!