Applications in the pharmaceutical field: D-alanine is an important intermediate in the synthesis of various drugs, such as those with antibacterial, antiviral, and anti-tumor activities. In the development of new antibiotics, D-alanine plays a role in constructing the key structures of the drugs, which helps to enhance the specificity of the drugs against pathogens and reduce their toxicity to normal human cells. As a food additive, it can be used as a nutritional fortifier. Due to its special optical properties, adding D-alanine to certain functional foods can help regulate the body's metabolic processes and boost immunity. It can also improve the flavor and texture of foods, and is used in sports nutrition products and elderly health supplements. In the cosmetics industry, D-alanine can be used as a skin conditioner. It promotes the metabolism of skin cells, enhances skin hydration, reduces the appearance of wrinkles and fine lines, and makes the skin smoother and more delicate. Additionally, D-alanine has antibacterial properties, which contribute to the stability and safety of cosmetics.