Yeast are microscopic single-celled organisms that are part of the fungus group. A key element in baking, yeast can also be used in skincare formulas to restore damaged skin cells and condition the complexion. As a source of the antioxidant beta-glucan, yeast can often be found in hydrating and anti-ageing products. When used in beauty formulas, yeast works to strengthen the skin’s structure and reduce redness and irritation.