What it is
Isoleucine is one of the standard amino acids and is used in skin care as a small, water-soluble conditioning agent. As a building block found naturally in skin proteins and part of the skin's natural moisturizing factor, it is included to help condition and soften the surface. It is typically used at low levels, often alongside other amino acids.
Safety & warnings
Amino acids such as isoleucine are skin-compatible and generally very well tolerated, with a low likelihood of irritation. It is not a fragrance allergen and is not associated with comedogenicity.
Origin & sourcing
Cosmetic isoleucine is most often produced by fermentation, yielding the naturally occurring L-form of the amino acid.
Questions everyone asks
What does isoleucine do in skin care?
It is an amino acid used as a skin-conditioning and humectant ingredient that helps soften and condition the skin surface, often paired with other amino acids.
Is isoleucine natural?
It is a naturally occurring amino acid, and the cosmetic form is typically made by fermentation to yield the natural L-isoleucine.