Everyone knows weekly manicures have their consequences—hello, dwindling bank account—but that may not be the only way it’s hazardous. The reality is, nail polish is the most toxic cosmetic there is, so painting your nails every week is like coating them with a medley of dangerous toxins. There’s formaldehyde, phthalates, acetone, toluene and benzophenones—all proven to damage your eyes, brain, lungs, endocrine system, respiratory system, you name it. So, what, we’re supposed to run around bare-tipped forever? Not necessarily. If you apply polish in adequately ventilated rooms, it should be OK, but you definitely shouldn’t be changing and reapplying your polish several times a week.