Made up of amino acids, these are the building blocks of protein. Protein (specifically collagen and elastin) are essential for healthy, youthful skin. "This is a great ingredient for anyone concerned with signs of aging, since they promote collagen and elastin synthesis to improve fine lines, wrinkles, elasticity and firmness," explains Shah. Also nice: Unlike other anti-aging ingredients (we're talking about you, retinol), peptides are typically well-tolerated by most skin types and less likely to cause irritating side effects. #Sold.
