Leucine

Leucine is a branched-chain essential amino acid used in cosmetics as a water-soluble humectant and conditioning agent. It's included to bind moisture at the surface, softening feel and supporting a comfortable finish in leave-on and rinse-off products.
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Ingredient Snapshot

Overview
An amino acid that binds moisture for a smoother, softer feel.
Category
Hydration, Skin Conditioning, Barrier Support
Type
Humectant

Ingredient Ratings

Overall Rating

Great

Comedogenic Risk

None

Skin Benefits

Attracts and retains water at the skin's surface for a smoother, more supple feel. Can improve slip and softness without heaviness.

Uses In Skincare & Cosmetics

Appears in serums, lotions, and moisturizers, as well as hydrating toners and gel cleansers to improve skin feel.

Comedogenic Rating

This ingredient is not typically evaluated for comedogenicity, and no standardized rating is available.

Safety

Generally well tolerated with low irritation potential at cosmetic levels. Patch test if skin is highly sensitive or compromised. No notable cosmetic-specific restrictions at typical use concentrations.

Is Leucine a Good Ingredient?

Rated Great because this amino acid humectant is versatile, stable, and well tolerated, delivering dependable surface hydration with minimal irritation risk. Its benefits stay mainly in moisturization, but its consistent performance is what earns the top rating.

Products with Leucine

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