Lysine HCI Best Humectant Hydration Anti-Ageing Lysine HCI at a glance Amino acid salt May be animal-derived or made in a lab Plays a role in helping keep skin hydrated Produces supportive substances that keep skin looking youthful and smooth Lysine HCI description Lysine HCI is an amino acid salt that may be animal-derived or made in a lab (Paula’s Choice uses the synthetic form). Like all amino acids and their derivatives, lysine HCI plays a role in keeping skin hydrated by aiding the balanced transport of water through skin’s layers. Lysine also plays a role in helping skin produce supportive substances that keep it looking smooth and youthful. Related ingredients: Lysine Amino Acids