Humectant

Isoleucine

Essential BCAA amino acid — Isoleucine is a component of the skin's NMF and is part of the BCAA triad along with Leucine and Valine. It participates in the synthesis of antimicrobial skin peptides and supports the microbiome.

NMFBCAAAntimicrobial peptidesMicrobiome

✓ Safe

Comedogenic Rating

0/5

Irritation Potential

0/5

What is it?

Isoleucine (ізолейцин, Ile) — an essential aliphatic amino acid with a branched chain (BCAA). In INCI: Isoleucine. It is part of the skin's NMF. Together with Leucine and Valine, it forms the BCAA triad. Research shows that Isoleucine stimulates the synthesis of antimicrobial peptides (beta-defensins) in keratinocytes — a unique property among amino acids.

NMF-active in complex amino acid formulas. In some research products, it is used to support the skin's natural antimicrobial defense. Often included in Amino Acid Complex.

Key Benefits

✦

Hydration through NMF pool

Isoleucine is part of the natural amino acid reservoir of NMF and retains moisture in the stratum corneum — a standard humectant function of NMF amino acids.

◈

Support for antimicrobial peptides

Research shows that Isoleucine can stimulate the synthesis of beta-defensin 2 in keratinocytes — a natural antimicrobial peptide of the skin. In cosmetics, this is more about supporting a healthy microbiome and barrier rather than treating infections.

✧

BCAA synergy for protein synthesis

Together with Leucine and Valine, it activates the mTOR pathway of protein synthesis in cells — supports skin recovery and regeneration after stress.

Suitable for

For all skin typesFor dehydrated skinFor skin with a weakened barrier

Main Actions

✓ NMF hydration✓ Support for antimicrobial peptides✓ Protein synthesis

Isoleucine in BCAA complexes

Isoleucine works best not as a standalone "hero," but as part of an amino acid complex along with Leucine, Valine, Serine, Glycine, and Sodium PCA. In such formulas, it supports NMF, barrier comfort, and a balanced microbiome, but does not replace anti-inflammatory or antibacterial actives in acne or infections.

CategoryHumectants

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