Ornithine is an amino acid produced in the urea cycle by the splitting off of urea from arginine. It is a central part of the urea cycle, which allows for the disposal of excess nitrogen. Ornithine is also a precursor of citrulline and arginine. Arginine stimulates the pituitary release of growth hormone. Burns or other injuries affect the state of arginine in tissues throughout the body. As de novo synthesis of arginine during these conditions is usually not sufficient for normal immune function, nor for normal protein synthesis, ornithine may have immunomodulatory and wound-healing activities under these conditions (by virtue of its metabolism to arginine).

L-carnitine (L-beta-hydroxy-gamma-N,N,N-trimethylaminobutyric acid) is conditionally necessary for mitochondrial transport and metabolism of long-chain fatty acids, and thus for myocardial energetic metabolism. D-carnitine is not biologically active and might interfere with proper utilization of the L isomer, and so there are claims that the racemic mixture (DL-carnitine) should be avoided. The pharmacological effects of carnitine are stereospecific: L-carnitine was effective in various animal and clinical studies, while D- and DL-carnitine was found to be ineffective or even toxic to some cells and tissues, such as muscle cells and the myocardium. DL-carnitine caused symptoms of myasthenia and cardiac arrhythmias, which disappeared after L-carnitine administration.

Creatinine is a product of metabolism of creatine phosphate, a molecule that serves as a rapidly mobilizable reserve of a brain and skeletal muscle. Creatinine is excreted by kidneys with little or no reabsorption. Serum creatinine is the most commonly used indicator of renal function.

HYDROXYPROLINE, a hydroxylated form of the imino acid proline, is a major component of the protein collagen. For this reason, HYDROXYPROLINE content in biological fluids is used as a parameter of collagen catabolism, especially bone resorption or tissue degradation. A deficiency in ascorbic acid can result in impaired HYDROXYPROLINE formation.

Asparagine is a non-essential amino acid, which is synthesized in the human body from L-aspartate by Asparagine synthetase. Asparagine is required for the synthesis of many important cellular proteins in normal human cells. Many tumor cells do not have this capacity, due to a lack of the enzyme L-asparagine synthetase, and therefore require an exogenous supply of the amino acid. This amino acid participates in the functions of the brain and nervous system. Asparagine may come from food or be taken as a dietary supplement.

Taurine is a semi-essential amino acid and is not incorporated into proteins. Taurine is considered conditionally essential because it cannot be synthesized by infants younger than 4-6 weeks, and it may not be adequately synthesized in patients receiving long-term parenteral nutrition and patients with short-term hypermetabolic conditions. In mammalian tissues, taurine is ubiquitous and is the most abundant free amino acid in the heart, retina, skeletal muscle, brain, and leukocytes. Taurin occurs naturally in fish and meat. The mean daily intake from omnivore diets was determined to be around 58 mg. Taurine is a component of energy drinks, with many contain 1000 mg per serving. In medicine, taurine supplementation demonstrated efficacy in relieving symptoms of heart failure, hepatitis, hypertension and psychotic disorder. Taurine exerts many physiological functions, including membrane stabilization, osmoregulation and cytoprotective effects, antioxidant and anti-inflammatory actions as well as modulation of intracellular calcium concentration and ion channel function. In addition taurine may control muscle metabolism and gene expression, through yet unclear mechanisms. The cellular and biochemical mechanisms mediating the actions of taurine are not fully known.

L-serineThe is a non-essential amino acid. L-serine and the products of its metabolism have been recognized not only to be essential for cell proliferation, but also to be necessary for specific functions in the central nervous system. The findings of altered levels of serine and glycine in patients with psychiatric disorders and the severe neurological abnormalities in patients with defects of L-serine synthesis underscore the importance of L-serine in brain development and function. L-serine supplementation is in trials for the treatment of several CNS diseases such as Alzheimer's disease, Hereditary sensory and autonomic neuropathy type 1 and Amyotrophic Lateral Sclerosis

Proline (L-Proline) is one of the twenty amino acids used in living organisms as the building blocks of proteins. Proline is a non-essential amino acid that is synthesized from glutamic acid. It is an essential component of collagen and is important for proper functioning of joints and tendons. Proline is used in pharmaceuticals as an excipient and as an active substance in nutritional supplements. Proline is not commonly used in pharmaceuticals as an excipient. It is approved for use in Privigen (IVIg) and Hizentra (SCIg) solution for injection as a stabiliser for IgG. Proline is also contained in low amounts in several vaccines, e.g. Havrix 720 Kinder (Hepatitis A).