IODINE I-123 is a radioactive isotope of iodine used in nuclear medicine imaging, including single photon emission computed tomography (SPECT) and X-ray computed tomography (X-Ray CT) scans. Iodine-123 is usually supplied as sodium iodide (NaI) and hypoiodite (OI−) in dilute sodium hydroxide solution, at high isotopic purity. 123I is the most suitable isotope of iodine for the diagnostic study of thyroid diseases. The half-life of approximately 13.13 h (hours) is ideal for the 24-h (hour) iodine uptake test and 123I has other advantages for diagnostic imaging thyroid tissue and thyroid cancer metastasis. The iodine is taken up by the thyroid gland and/or cancer metastasis and a gamma camera is used to functional images of the thyroid for diagnosis. Quantitative measurements of the thyroid can be performed to calculate the iodine uptake (absorption) for the diagnosis of hyperthyroidism and hypothyroidism. This is administered to a patient in capsule form, by intravenous injection, or in a drink.

Strontium is a soft, silver-yellow, alkaline-earth metal, existing either in the elemental state or as the divalent ion. Strontium occurs naturally in the earth's mantle as a mixture of four stable isotopes, i.e. Sr-84, Sr-86, Sr-87, and Sr-88. Of these, Sr-88 is the most prevalent form, comprising about 83% of natural strontium. Natural stable strontium is abundant in the environment and can be found in all plant species. Consuming 75% of production, the primary use for strontium is in glass for color television cathode ray tubes, where it prevents X-ray emission. Acantharea, a relatively large group of marine radiolarian protozoa, produce intricate mineral skeletons composed of strontium sulfate. In biological systems, calcium is substituted in a small extent by strontium. In the human body, most of the absorbed strontium is deposited in the bones. The ratio of strontium to calcium in human bones is between 1:1000 and 1:2000, roughly in the same range as in the blood serum. The human body absorbs strontium as if it were its lighter congener calcium. Because the elements are chemically very similar, stable strontium isotopes do not pose a significant health threat. The average human has an intake of about two milligrams of strontium a day.

Phosphorus P-32 (P-32) is the phosphorus isotope whose nucleus consists of 15 protons and 17 neutrons. Phosphorus P-32 is one of the most commonly used research emitters and is the one with the highest energy. Its use in molecular biology has become widespread by the use of specific high-activity nucleotides to mark DNA. Phosphorus P-32 may also be used in phosphorylation reactions. More precisely, it is used in the study of the migration of fertilizers (phosphates) in soils. In the medical field, phosphorus P-32 has been used for the treatment of polyglobulia, but this is increasingly rare. Emitted by phosphorus P-32, beta particles directly damage cellular DNA and, by ionizing intracellular water to produce several types of cytotoxic free radicals and superoxides, indirectly damage intracellular biological macromolecules, resulting in tumor cell death.

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).

Isopentane is a colorless liquid with an alcohol or gasoline-like odor. It is used as a solvent, and as a blowing agent in making plastics. Inhalation can cause dizziness, drowsiness, headache, and unconsciousness. Skin exposure leads to dry skin. Ingestion can cause nausea and vomiting. Isopentane is an aspiration hazard. If swallowed the substance easily enters the airways and could result in aspiration pneumonitis. Isopentane causes CNS depression between 270 and 400 mg/L, and is a weak cardiac sensitizer. Isopentane is an excipient. In cosmetics and personal care products, Isopentane is used in the formulation of shaving cream, cleansing products, hair conditioners, and makeup. Isopentane is a component of Ralgex Freeze Spray, which is used for the symptomatic relief of muscular pain and stiffness, including backache, sciatica, lumbago, fibrositis, rheumatic pain. Ralgex Freeze Spray contains Glycol Monosalicylate 10% w/w, Methoxymethane 14.41% w/w and Isopentane 67.77% w/w. Ralgex Freeze Spray is also used for the symptomatic relief of sprains, strains and bruises associated with sports injuries, and stiffness following sporting exercise.

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).

Guanosine is an endogenous guanine nucleoside. Guanosine was shown to be protective in several in vitro and/or in vivo experimental models of central nervous system (CNS) diseases including ischemic stroke, Alzheimer's disease, Parkinson's disease, spinal cord injury, nociception, and depression. The mechanisms underlying the neurobiological properties of guanosine seem to involve the activation of several intracellular signaling pathways and a close interaction with the adenosinergic system, with a consequent stimulation of neuroprotective and regenerative processes in the CNS. Several guanosine analogues, i.e. acyclovir (and its oral prodrug valaciclovir), penciclovir (in its oral prodrug form, famciclovir) and ganciclovir, are widely used for the treatment of herpesvirus (i.e. HSV-1, HSV-2, VZV and HCMV) infections.