Made Up of Amino Acids Glycine, Proline, Hydroxyproline and Arginine. Help With Firmness and Elasticity. Features: Provides the Building Blocks of Our Skin. Collagen Serum | Living SocialMade Up of Amino Acids Glycine, Proline, Hydroxyproline and Arginine. Help With Firmness and Elasticity. Features: Provides the Building Blocks of Our Skin. Collagen Serum | Living Social