Micronutrients are vitamins and minerals — like vitamin A, vitamin C, potassium, and magnesium — that your body needs in small amounts to function. They support the brain, muscles, skin, bones, nerves, circulation, and immune system. Many are “essential,“ meaning your body can't make them on its own. Together, they keep you healthy and performing at your best. Deficiencies are associated with heart disease, diabetes, certain cancers, osteoporosis, and more.