Skin Respiratory Factors

Skin respiratory factors (SRF), also called tissue respiratory factors (TRF), have been used in cosmetics for their ability to renew and revitalize the skin. These ingredients revitalize cellular metabolism through the stimulation of cell respiration. The ability of an ingredient to stimulate cell respiration and cellular metabolism can be determined by Warburg assay, which measures oxygen uptake in living cell homogenates. As cell respiration and metabolism increase, cell energy increases, as evidenced by increased cellular ATP levels measured in the cell suspension [64].

Although a number of botanical ingredients with the ability to enhance cell respiration have been isolated, the most abundant source is baker’s yeast [65]. However, unlike beta-glucans, which are isolated from the cell walls of baker’s yeast, compounds that stimulate cellular respiration are extracted from the cytoplasm. These cytoplasmic elements generally contain mitochondrial components of the cell, which can enhance cellular energy [66].

As skin ages, it exhibits a certain amount of physiologic fatigue, which is compounded by oxidative stress and environmental factors. This fatigue, which increases with age, is paralleled by the progressive decrease in cellular energy and metabolism as well as diminished cellular function.The addition of ingredients to anti-aging skin care that contain mitochondrial cytoplasmic yeast extracts can result in the stimulation of cellular respiration followed by enhanced cellular metabolism, vitality, and increased cell renewal.