Application of L-threonine in Cosmetics

L-Threonine is an essential nutritional amino acid with various potential applications in cosmetics, primarily in the following aspects:  

1. Moisturizing Effect  

L-threonine has excellent hygroscopic and moisturizing properties, allowing it to absorb moisture from the air and retain it on the skin surface. It forms a protective moisture layer that prevents water loss, keeping the skin hydrated, soft, and smooth. When used in combination with other moisturizing agents such as glycerin and hyaluronic acid, it can exert a synergistic effect to enhance moisture retention. This makes it particularly suitable for dry skin care products, such as moisturizing lotions and creams.  

2. Skin Repair and Regeneration  

L-Threonine is one of the essential raw materials for the synthesis of collagen and elastin in the skin. It participates in skin cell metabolism, promotes collagen and elastin production, and helps improve skin elasticity and resilience. This reduces the appearance of wrinkles and fine lines, making the skin firmer and more radiant. Additionally, it aids in skin cell regeneration and repair, accelerating wound healing. It has a certain repairing effect on damaged skin, such as acne-prone and sensitive skin, making it suitable for use in repair serums, face masks, and other skincare products.  

3. Antioxidant Properties  

L-Threonine exerts antioxidant effects by scavenging free radicals, reducing oxidative damage to skin cells, and slowing down skin aging. It works synergistically with other antioxidants such as vitamin C and vitamin E to strengthen the skin’s antioxidant defense system. This enhances the skin's resistance to environmental aggressors such as UV radiation and pollution, preventing pigmentation and dullness. It is commonly used in anti-aging skincare products, such as antioxidant serums and day creams.  

4. Enhancing Skin Barrier Function  

L-Threonine helps maintain the integrity of the skin barrier, strengthening its ability to protect against harmful external substances such as bacteria and pollutants while preventing the loss of moisture and essential nutrients from the skin. It regulates the lipid balance between skin cells, making the skin barrier more stable. This makes it particularly beneficial for sensitive and damaged skin, and it is often included in skincare products designed to repair the skin barrier, such as barrier repair creams and cleansers.  

5. Hair Care  

In hair care products, L-Threonine can penetrate the hair fiber and bind with keratin, improving hair strength and resilience while reducing breakage and split ends. It also forms a protective layer on the hair surface, enhancing shine and smoothness, making the hair softer and easier to manage. Additionally, it promotes scalp blood circulation and nourishes hair follicles, supporting hair growth and helping to prevent hair loss. As a result, it is widely used in shampoos, conditioners, and hair masks.  

6. Oral Care  

L-Threonine can be added to oral care products such as toothpaste and mouthwash. It helps regulate the microbial balance in the mouth, inhibiting the growth of harmful bacteria and preventing dental issues such as cavities and bad breath. Additionally, it has a soothing effect, helping to reduce inflammation and sensitivity of the oral mucosa, thereby promoting a healthier oral environment.