Nail Envy | Nail Strengthener (Multiple Shades)Stronger, healthier nails start here. OPI Nail Envy Nail Strengthener is a strengthening treatment designed to help reinforce weak, brittle, or peeling nails. It builds a protective layer over the natural nail to support growth, improve resilience, and reduce breakage over time. Wear it on its own for a clean, natural look or as a base coat under polish. With consistent use, nails feel stronger, smoother, and less prone to splitting.