Biotin

Biotin is vitamin B7, a water-soluble vitamin. It is one of the three micronutrients Perla groups under the BioGlow Complex®, alongside zinc and manganese.

Water-soluble means the body holds no reserve of it, which is why biotin is taken daily rather than in a course. That is the argument for putting it in something you drink every morning rather than in a treatment used once a week.