Whitens, Softens & Conditions Nails. For discolored & thickened nails. Triple action formula. Diabetic friendly. Easy to use brush applicator Flexitol Nail Revitalizer Gel is a convenient way to care for, condition and treat discolored and thickened nails on both feet and hands. This triple action formula contains: an Optical brightener to remove discoloration, Urea to soften thickened nails and Keratin to condition and restore nail quality.