At Viviscal, we understand the science of healthy hair growth from the inside out. Formulated with hair building blocks Biotin and Keratin, and fortified with marine Collagen and Seaweed extract, Viviscal Hair Thickening Serum is a lightweight leave-in treatment that coats each hair strand creating multi-dimensional density without frizz leading to thicker, fuller-looking hair*. For best results, nourish your hair from within with Viviscal Hair Supplements.