What common nail product can lead to discoloration if used without a specific base?

Dark nail polish is known to cause discoloration of the natural nail if applied without a proper base coat. The pigments present in dark nail polishes can penetrate the nail plate, leading to yellowing or staining over time. A base coat serves as a protective barrier that prevents these pigments from adhering directly to the nail surface, thereby minimizing the risk of discoloration.

Using a base coat not only helps in preserving the natural color of the nails but also enhances the longevity of the nail polish and provides a smooth surface for even application. Hence, it is essential to apply a suitable base before using darker shades to avoid potential damage and maintain the nails' appearance.