Trind Nail Revive Natural is FORMALDEHYDE FREE nail strengthener, which not only strengthens weak nails, but also keeps them supple. Used as a treatment for two weeks, after this period, apply once a week. The unique formula brings the protein molecules in the nail firmly together, which creates a very strong structure but still allows the nail to flex so it does not chip or split. The natural nail moisture will not be lost, keeping the nail supple. Combine it with the Nail Balsam for the ultimate nail care.