Niacinamide, also called nicotinamide, is a form of vitamin B-3. Niacinamide helps build keratin, a type of protein that keeps your skin firm and healthy. Niacinamide can also help stimulate your skin to grow a ceramide (lipid) barrier, which can, in turn, help retain moisture. This is beneficial for all skin types, especially if you have eczema or mature skin. Finally, it minimizes pore appearance and regulates oil.