Niacinamide, commonly known as nicotinamide, is an important nutrient in the form of vitamin B-3. A B-3 shortage can cause skin, renal, and brain problems. Niacinamide supplementation can help avoid B-3 deficiency. And there's a lot more to this vitamin, especially when it comes to skin health in general. Although additional study is needed, topical niacinamide may be beneficial in the treatment of some skin disorders such as acne and eczema.