As a regular polish-wearer, my never-ending cycle of manicures has left my nails dry and prone to peeling, which is why I don't expose my nails to just any base coat. Butter London Horse Power Nail Fertilizer ($18) provides a perfect layer of nourishment for my worn-out nails. It's formulated with the medicinal herb horsetail to feed nails with nutrients, particularly silica, which is known to strengthen nails and help them grow faster and healthier. Wear it under your favorite polish, or wear it alone for a naturally glossy look. You can use it for as long as you need to help your nails grow out, but the directions indicate you should give your nails a break every four weeks of continued use. Medicine for your nails? Now you know the prescription.