Epidermal growth factor (EGF) is a single polypeptide of 53 amino acid residues which is involved in the regulation of cell proliferation. Egf exerts its effects in the target cells by binding to the plasma membrane located EGF receptor. The EGF receptor is a transmembrane protein tyrosine kinase.
EGF stimulates cells in the skin called fibroblasts, which produce collagen and elastin to clarify, thicken, and tighten skin. As you age, your EGF decreases and so too does skin's elasticity, leading to signs of aging such as dullness, wrinkles, lines, and general skin-sagging.