Yellow nails: Often, yellow discoloration is just your nail reacting to a product you’re using, like nail polish or acrylic nails. If you’re all about weekly manicures and nail art, give your nails a breather (experts suggest no more than two manicures a month)—and swap in tea tree oil or vitamin E to help nourish your nails naturally. If they don’t grow in clear, the yellowish tint may be caused by something else, like a fungal infection.
White spots: A tiny trauma (i.e., smacking your finger against the table—ouch) is often the likely culprit of light-colored spots on the nail, called punctate leukonychia. Thankfully, they’ll eventually disappear. Just have patience—it takes about six months to grow a new fingernail from start to finish. But if the spots continue to stick around, check in with your doctor: There may be an underlying issue, like a zinc deficiency, at play.
Black streaks: This is a serious one—see your doctor right away if you notice any dark or black discoloration on your nails, especially if it feels painful. Melanoma can sometimes cause black lines or stripes to appear on the nail, so pay attention to this clue if skin cancer runs in the family.