Humectant

Leucine

Essential branched-chain amino acid (BCAA) — a key regulator of protein synthesis via the mTOR pathway. In cosmetics, it moisturizes as an NMF component, strengthens the barrier, and stimulates collagen synthesis. A natural component of human skin.

BCAAEssential amino acidNMF componentStimulates protein synthesis

✓ Safe

Comedogenic Rating

0/5

Irritation Potential

0/5

What is it?

L-Leucine (INCI: Leucine) — an essential amino acid obtained only from food (meat, cheese, eggs, legumes). Molecular weight ~131 Da. Partially soluble in water. In the skin: part of the NMF of the stratum corneum, present in keratin and collagen. Mechanism of action at the cellular level: activates mTORC1 → increases protein synthesis (keratin, collagen) in keratinocytes and fibroblasts. In cosmetics: moisturizer + stimulator of cellular activity + component of "amino acid complex" formulas.

Moisturizers with amino acid complex, NMF-replenishing formulas, barrier-strengthening products, serums for skin elasticity.

Key Benefits

✦

Moisturization and NMF support

Leucine — a hygroscopic amino acid in the NMF, which, along with other amino acids (serine, glycine, alanine, proline), retains water in the stratum corneum. When applied topically: replenishes lost NMF, especially effective in combination with sodium PCA, urea, and hyaluronic acid. Reduces TEWL, improves the comfort of dry skin.

◈

Stimulation of keratin and collagen synthesis via mTOR

Leucine — the only amino acid that directly activates mTORC1 without additional stimuli. Result: accelerated keratin synthesis in keratinocytes → strengthening of the stratum corneum. In fibroblasts: mTOR activation → synthesis of collagen and elastin. For the skin: potential strengthening of the barrier and increased elasticity with regular use.

✧

Protection and restoration of damaged skin

Leucine plays a key role in recovery after damage: it is a building block for new skin proteins. Studies have shown: topical application of L-leucine accelerates the healing of minor skin injuries, improves the restoration of barrier function after aggressive cleansing or chemical procedures. Especially effective in combination with other BCAAs (valine, isoleucine).

Suitable for

Dry skinDamaged barrierMature skin

Main Actions

✓ Moisturization and NMF support✓ Stimulation of keratin synthesis via mTOR✓ Strengthening the barrier

BCAA in cosmetics: leucine, valine, isoleucine

Three branched-chain amino acids (BCAA) — leucine, valine, isoleucine — often found together in "amino acid complex" formulas. Leucine: the most powerful mTOR activator, focusing on protein synthesis. Valine: focus on recovery and barrier. Isoleucine: focus on antimicrobial activity (beta-defensin) and healing. Together: comprehensive support for NMF and barrier. All three: essential, safe, well-tolerated.

CategoryHumectants

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