Milk Amino Acids
INCI: MILK AMINO ACIDS
Reviewed by Rosie · Last updated 14 Aug 2026
A protein derivative that conditions skin and hair whilst supporting moisture retention
Best For Skin Types
All, Dry, Sensitive
Addresses
Usage Frequency
Daily
What Is Milk Amino Acids?
Milk amino acids are small protein fragments derived from milk through enzymatic breakdown. This process creates individual amino acids and peptides—the building blocks of proteins—that are small enough to be absorbed or interact with the skin's surface. In skincare formulations, they function as conditioning agents that help improve hydration and the skin's overall feel.
These ingredients are commonly used in both skincare and haircare products because of their capacity to interact with the skin barrier and support moisture balance. They are distinct from whole proteins, which are too large to penetrate significantly into the skin.
How It Works
Milk amino acids work primarily through humectant and emollient properties. Humectants draw water from deeper skin layers and the environment into the stratum corneum (the outermost layer), whilst emollients form a light film that helps reduce transepidermal water loss—the natural evaporation of moisture from the skin. This combination helps improve skin hydration and comfort.
The amino acids themselves may also provide minor nutritional support to the skin surface, though systemic absorption and meaningful penetration into deeper layers remains limited for topical application.
Clinical Evidence & References
Research on milk-derived nutrients shows promise for skin hydration. An 8-week controlled trial found that oral consumption of milk amazake (a fermented milk product rich in amino acids and B vitamins) led to measurable improvements in skin elasticity and hydration levels, with reduced transepidermal water loss.
However, topical application of milk amino acids specifically has less extensive clinical documentation. The evidence supports their use as moisturising agents in formulations, but individual studies on the ingredient in isolation are limited. They are generally considered well-tolerated and safe for regular use.
Published Research
How to Use
Milk amino acids work best when used as part of a complete skincare routine. They are most effective in hydrating serums, moisturisers, and conditioners, where they can remain in contact with the skin. For best results, apply to damp skin to maximise the humectant effect, and use consistently as part of your daily routine.
Safety & Precautions
Frequently Asked Questions
From the Clinic
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Take the skin quizOther forms of Milk Amino Acids
These appear on ingredients lists under different names but are the same substance. Milk Amino Acids is the common form.
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