We hear a lot about “safe” nail polishes these days, but it can be confusing as to what, exactly, those polishes really are. Is it best to go for 3-free? 5-free? 7-free? And what does it all mean? We spoke with three cosmetic chemists to get the lowdown on the whole thing, and then we found 33 nail polishes (in cute colors!) for you to shop, so you never have to worry about putting pretty polish on your nails again.