Up to 90% smoother looking nails, instantly! Fills ridges, salon strength. No DBP, Toluene, Formaldehyde. Salon tested Biotin, a vitamin found in oysters, & Spirulina, a marine extract, are known to help strengthen and nourish nails. What It Is A gel-like base coat, that smoothes ridges and imperfections for salon results at home. How It Works This Biotin & Spirulina enriched formula, with self-leveling action, fills ridges evenly. Hardens weak nails and adds density to thin nails to help prevent splitting. Even fi.