Arginine is a semi-essential amino acid because even though the body normally makes enough of it, supplementation is sometimes needed during critical illness and severe trauma. There have been numerous research studies focusing on using arginine to enhance wound healing and pressure ulcer prevention. It is required for promotion of nitrogen balance, cell proliferation, T lymphocyte function and collagen accumulation. It also changes into nitric oxide, which is known for its vasodilatory and angiogenic properties.