Core Composition of Silk Amino Acids
Silk amino acids, also known as silk mixed amino acids or hydrolyzed silk fibroin amino acids, are water-soluble mixtures obtained through controlled hydrolysis of silk fibroin. Their core components include glycine (approximately 38%), alanine (approximately 34%), and serine (approximately 13%), along with smaller amounts of amino acids such as tyrosine and valine. The overall average molecular weight is approximately 90 Da, offering excellent water solubility. The material shows a positive ninhydrin reaction and a pH range of 5–7, meeting the fundamental requirements for cosmetic-grade raw materials.
Key Amino Acids for Moisturizing and Repair
Among the functional components related to moisturizing and skin repair, serine, glycine, and alanine play dominant roles. Serine is highly hydrophilic and is an important component of the skin's Natural Moisturizing Factor (NMF). Glycine exhibits excellent compatibility with human skin and supports normal cellular metabolism. Alanine contributes to maintaining skin barrier stability. Together, these three amino acids form the core moisturizing and repairing system of silk amino acids. Other amino acids, such as tyrosine, may exhibit antioxidant properties but play a comparatively secondary role in moisturizing and repair functions.
Mechanism of Moisturizing and Repair
Serine rapidly attracts water molecules through its hydrophilic groups, forming a moisture-retaining film on the skin surface while penetrating the stratum corneum to replenish NMF and improve epidermal hydration. Glycine can penetrate deeper skin layers and participate in protein synthesis, supporting the repair of compromised skin barriers and enhancing skin resilience. Alanine improves ingredient solubility and formulation compatibility, helping reduce external irritation while stabilizing the moisture-retention film and extending hydration duration. Together, these amino acids create a complete functional pathway of rapid hydration, long-lasting moisture retention, and barrier support.
Industry Trends
In the global cosmetics market, demand for natural ingredients and barrier-supporting solutions continues to grow. As a naturally derived ingredient from silk protein, silk amino acids align well with the clean beauty trend due to their clear functional mechanisms and mild properties. In particular, procurement demand for cosmetic-grade silk amino acids in the Asia-Pacific, European, and North American markets has been growing at an annual rate exceeding 25%, making them a key growth driver among high-value cosmetic raw materials.