Original Formula Nail Envy Nail Strengthener 15ml / 0.5oz - pack 2. The most-asked-for brand in the industry! With a superior range of shades and the hottest special effects and textures, Original Formula is the go-to brand for nail fashion. From elegant classics to eye-popping brights, Original Formula has your color! Formaldehyde-free Maximum strength formula with Hydrolyzed Protein and Calcium helps nails grow harder, longer and stronger and resist peeling, cracking and splitting.