Citrulline (name derived from citrullus, the Latin word for watermelon, from which it was first isolated) is an amino acid. It is made from ornithine and carbamoyl phosphate in one of the central reactions in the urea cycle. It is also produced from arginine as a by-product of the reaction catalyzed by nitric oxide synthase (NOS) family. Citrulline supplements have been claimed to promote energy levels, stimulate the immune system and help detoxify ammonia (a cell toxin). Citrulline is not involved in protein synthesis. Several pharmacokinetic studies have confirmed that citrulline is efficiently absorbed when administered orally. Oral citrulline could be used to deliver arginine to the systemic circulation or as a protein anabolic agent in specific clinical situations (for example in case of malnourishment), because recent data have suggested that citrulline, although not a component of proteins, stimulates protein synthesis in skeletal muscle through the mammalian target of rapamycin signaling pathway. Citrulline is converted to L-arginine by argininosuccinate synthase. L-arginine is in turn responsible for citrulline's therapeutic effects. Many of L-arginine's activities, including its possible anti-atherogenic actions, may be accounted for by its role as the precursor to nitric oxide (NO).

Alanyl-glutamine is a widely used alternative supplement to L-glutamine in the production of biopharmaceuticals. The primary advantage of using L-alanyl-glutamine in place of L-glutamine is that it reduces the level of ammonia generated during cell culture. L-alanyl glutamine also acts as an antioxidant (peroxide) and anti-apoptosis (LPS-induced) factor. Ala-Glu may be used in cell culture and insect cell culture applications. It can be used in studies on injury and sepsis, and in the effects of irradiation on leucine and protein metabolism in vivo. Alanyl-glutamine is used as dipeptide infusion solution, which is given as part of parenteral and/or enteral nutritional therapy. When the intake of nutrients or food into the mouth or directly into the gut is not possible or it is not enough to supply the body’s needs then nutrients or foods can be given intravenously or through the gastrointestinal tract or a combination of both. This is especially important for people whose bodies are under physical stress from illness or recent surgery. During illness or after surgery the body requires nutrition or food. Amino acids are the building blocks used by the body to make proteins. Dipeptiven is usually given as a supplement to amino acid solutions or an amino acid containing infusion regimen as part of complete nutritional support.

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).

Glutathione (GSH, also called as reduced glutathione) is a tripeptide with many roles in cells. It conjugates to drugs to make them more soluble for excretion, is a cofactor for some enzymes such as, glutathione reductase, glutathione peroxidases, peroxiredoxins. Glutathione S-transferases catalyse the conjugation of GSH via a sulfhydryl group to electrophilic centers on a wide variety of substrates in order to make the compounds more water-soluble. As a part of homeopathic product, glutathione is used for temporary relief of symptoms related to Free Radical Toxicity including tingling in hands and feet, mood changes, frequent colds, poor digestion, fatigue, and constipation. In addition, for temporary relief of pain in the back from urinating, constant urging and frequent urination, kidneys sensitive to pressure, and pain from back extending down the thigh. Glutathione is an important nutrient for brain function and loss of glutathione has been implicated in Parkinson's disease. In phase II of the clinical trial was investigated whether administration of either dose of glutathione, as a nasal spray, improves PD symptoms over time in a population of individuals with Parkinson's disease (PD). In addition in phase II of clinical trial was shown, that reduced glutathione, an ingredient of RayGel™, has been helpful in decreasing some radiation therapy side effects to the skin. Reduced glutathione plays a vital role in both making DNA and cell repair. Cystic fibrosis (CF) is the most common inherited disease among the Caucasian population with considerable morbidity and reduced life expectancy. Glutathione (GSH) represents the first-line defence of the lung against oxidative stress-induced cell injury. Therapeutic approaches with inhaled GSH could improve the reduced lung antioxidant capacity in order to counterbalance the oxidant stress linked to the chronic airway inflammation and bacterial infection.

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.

Aceglutamide (INN, JAN) (brand name Neuramina), or aceglutamide aluminum (JAN, USAN) (brand name Glumal), also known as acetylglutamine, is a psychostimulant, nootropic, and antiulcer agent that is marketed in Spain and Japan. Aceglutamide functions as a prodrug to glutamine with improved potency and stability. Aceglutamide is used as a psychostimulant and nootropic, while aceglutamide aluminum is used in the treatment of ulcers. Aceglutamide can also be used as a liquid-stable source of glutamine to prevent damage from protein energy malnutrition.

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.

N-Acetyltyrosine is an acetylated derivative of the amino acid L-tyrosine. Ordinary L-tyrosine is less stable and also less soluble in water, which may result in reduced bioavailability. Acetylation enhances the solubility and stability of certain amino acids. N-Acetyltyrosine is commonly used in place of tyrosine in parenteral nutrition. It converts to tyrosine and then can be used in neurotransmitter treatment as a precursor of cathecholamine. N-Acetyltyrosine supports brain function by supporting the synthesis of the catecholamines norepinephrine and dopamine (neurotransmitters). N-Acetyltyrosine supplements are used to improve memory and cognitive performance in humans while they are experiencing psychological stress.

Butylated hydroxytoluene, commonly known as BHT, is an organic compound that is used in the food, cosmetic, and pharmaceutical industry as an antioxidant. BHT is a substituted derivative of phenol. BHT helps to prevent the formation of free radicals and oxidation. When used in food products, it delays oxidative rancidity of fats and oils, and prevents loss of activity of oil-soluble vitamins. It may be found in pharmaceutical gels, creams and liquid or gelatin capsules, tablets and other pharmaceutical dosage forms. The ability of oral BHT to lead to cancer is a controversial topic, but most food industries have replaced it with butylated hydroxyanisole (BHA). BHT was first used as an antioxidant food additive in 1954. BHT does have other commercial uses, as in animal feeds and in the manufacture of synthetic rubber and plastics, where it also acts as an antioxidant. The U.S. Food and Drug Administration has deemed that BHT is safe enough when used in limited concentrations. It currently permits its use in concentrations of about 0.01% to 0.02% in most foods. As an emulsion stabilizer in shortening, it may be used in a somewhat higher concentration, 200 parts per million.

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.