Biotin Biotin, also known as B7, is a water soluble vitamin from the Vitamin B family. It may be found in some skin creams.Related Articles: Can Nail Oils Really Help Nails Grow Faster?The Essential Role of Water and Oil in Nail HealthUnderstanding Polymer-Based Nail HardenersGel Polish After ChemotherapyNail Plate Calcium Deficiency: What White Spots Really Mean