Amino acid blends or complexes are used to support the small intestine based on scientifically validated roles of amino acids in gut health and intestinal function. The small intestine is responsible for nutrient absorption, and its mucosal lining is highly dependent on adequate amino acid supply for cell turnover, repair, and function. Several amino acids—such as glutamine, arginine, and threonine—are specifically important for the maintenance and integrity of the intestinal barrier and for supporting enterocyte (intestinal cell) health.

Scientific studies have shown that glutamine, for example, is the primary fuel source for enterocytes and plays a crucial role in preserving gut barrier function, promoting mucosal healing, and reducing intestinal permeability in various clinical scenarios (e.g., short bowel syndrome, mucositis, and critical illness). Other amino acids, such as arginine, are involved in modulating immune responses and supporting nitric oxide production, which is important for gut blood flow. Threonine is a key component of mucin, which forms the protective mucus layer in the gut.

Both in vitro and human studies provide evidence that amino acid supplementation can improve gut integrity and support recovery from injury or stress. While individual amino acids have been most studied, blends or complexes are commonly used in clinical nutrition to provide a broad spectrum of these building blocks, especially when dietary intake is insufficient or increased demand exists. Overall, there is strong scientific rationale and evidence for the use of amino acid blends to support the small intestine.