Formulations and methods for skin care

A topical formulation, comprising:

• as free amino acids, a therapeutically effective amount of a combination of glutamine, glycine, alanine, and serine, or salts thereof, and
• at least one additional free amino acid selected from the group consisting of valine, isoleucine, arginine, threonine, and tryptophan, salts thereof, and any combination thereof,
• wherein each free amino acid has a ratio to each of the other free amino acids of:
• 1:100 or greater,
• wherein the therapeutically effective amount improves barrier integrity of skin cells, when tested by a method detecting expression of an EGF skin barrier marker gene and determining that the EGF skin barrier marker gene is upregulated by a 1.5-40 average fold change of formulation treated as compared to untreated skin,
• wherein the therapeutically effective amount improves barrier integrity of the skin and/or skin barrier repair.