Beta-carotene is found in many foods and is sold as a dietary supplement. Beta-carotene is a carotenoid, weak antioxidant; precursor of vitamin A, which is essential for vision and growth. Used to reduce the severity of photosensitivity reactions in patients with erythropoietic protoporphyria (EPP). Has been used in high-dose antioxidant supplements containing ascorbic acid and vitamin E with zinc in high-risk patients with age-related macular degeneration. Beta-carotene is also used to decrease asthma symptoms caused by exercise; to prevent certain cancers, heart disease, cataracts; and to treat AIDS, alcoholism, Alzheimer’s disease, depression, epilepsy, headache, heartburn, high blood pressure, infertility, Parkinson’s disease, rheumatoid arthritis, schizophrenia, and skin disorders including psoriasis and vitiligo.

Dihydrotachysterol (DHT) is a synthetic vitamin D analog activated in the liver that does not require renal hydroxylation like vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Dihydrotachysterol is used to treat hypocalcemia, hypoparathyroidism, and prevention of tetany. Dihydrotachysterol is hydroxylated in the liver to 25-hydroxy-dihydrotachysterol, which is the major circulating active form of the drug. Once hydroxylated to 25-hydroxy-dihydrotachysterol, the modified drug binds to the vitamin D receptor. The bound form of the vitamin D receptor serves as a transcriptional regulator of bone matrix proteins, inducing the expression of osteocalcin and suppressing synthesis of type I collagen. Dihydrotachysterol also increases renal phosphate excretion.

Menadione, a drug belong to class of Vitamin K, is prescribed for the treatment of hemorrhage, vitamin K deficiency, moderate to severe forms of hypoprothrombinaemia in adults and children. Menadione is a synthetic form of vitamin K, a lipid-soluble vitamin. Vitamin K is a vital cofactor for the biosynthesis of prothrombin, factor VII, IX, X, protein C and protein S. Menadione supports the functions of osteocalcin. Large doses of menadione have been reported to cause adverse outcomes including hemolytic anemia due to glucose-6-phosphate dehydrogenase deficiency, neonatal brain or liver damage, or neonatal death in some rare cases.

Pantothenic acid (known as Vitamin B5) is a water-soluble member of the B-vitamin family that is converted into 4’-phosphopantetheine, which is then converted to co-enzyme A (CoA) via adenosine triphosphate. Pantothenic acid regulates epidermal barrier function and keratinocytes differentiation via CoA metabolism. Pantothenic acid is incorporated into co-enzyme A and protects cells against peroxidative damage by increasing the level of glutathione. A recent feasibility study has also shown that daily oral supplementation of a nutritional agent containing pantothenic acid for 8 weeks was feasible and safe. It was discovered the different pharmacological implementation of pantothenic acid, such as treatment of acne, obesity. Existed some reports, mentioned efficacy using pantothenic acid in systemic lupus erythematosus. Significant reduction in morning stiffness, degree of disability, and severity of pain was reported for persons taking pantothenic acid in case of osteoarthritis and rheumatoid arthritis. Vitamin B5 may increase the effects of a group of drugs called cholinesterase inhibitors, which are used to treat Alzheimer's disease. That might lead to severe side effects.

Cobalamin (vitamin B12) is a cobalt-containing, B complex vitamin. B12 group (cobalamins) consist of cyanocobalamin, hydroxocobalamin, methylcobalamin and cobalamid. Neither plants nor animals are independently capable of constructing vitamin B12. Only bacteria and archaea have the enzymes required for its biosynthesis. Therefore, humans must absorb it from food. Excellent sources of B12 are foods of ruminant origin, so dairy and meat products play an important role in efforts to meet the official daily B12 intake. Vitamin B12 deficiency can potentially cause severe and irreversible damage, especially to the brain and nervous system. Vitamin B12 is used to treat vitamin B12 deficiency, including pernicious anemia.

Melatonin (5-methoxy N-acetyltryptamine) is a hormone synthesized and released from the pineal gland at night, which acts on specific high affinity G-protein coupled receptors to regulate various aspects of physiology and behaviour, including circadian and seasonal responses, and some retinal, cardiovascular and immunological functions. Melatonin is also made synthetically and available without a prescription as an over-the-counter (OTC) dietary supplement in the U.S. Melatonin supplementation has many uses, however, it has been widely studied for treatment of jet lag and sleep disorders. Parents may consider using melatonin to help their child who has a trouble falling asleep. A medical professional should always evaluate insomnia or other sleeping disorders in children. Additionally, melatonin has been shown to protect against oxidative stress in various, highly divergent experimental systems. There are many reasons for its remarkable protective potential. In mammals, melatonin binds to a number of receptor subtypes including high-affinity (MT1 and MT2) and low-affinity (MT3, nuclear orphan receptors) binding sites, which are distributed throughout the central nervous system and periphery.

Methylcobalamin (also known as mecobalamin, MeCbl, or MeB12) is one of the two forms of biologically active vitamin B12. Methyl-B12 is the principal form of circulating vitamin B12, hence the form, which is transported into peripheral tissue. Methylcobalamin is absorbed by the intestine by a specific mechanism, which uses the intrinsic factor, and by a diffusion process in which approximately 1% of the ingested dose is absorbed. Cyanocobalamin and hydroxycobalamin are forms of the vitamin that require conversion to methylcobalamin. Methylcobalamin alone or in combination with others compound are used to treat different diseases. Being a component of CEREFOLIN NAC it is used to treat Alzheimer's dementia. As a part of METANX® tablets is used for the dietary management of endothelial dysfunction in patients with diabetic peripheral neuropathy. Methylcobalamin exerted therapeutic effects on neuropathic pain in diabetics, possibly through its neurosynthesis and neuroprotective actions. The possible mechanisms can be considered as follows. (1) Methylcobalamin improved nerve conduction velocity; (2) methylcobalamin promoted injured nerve regeneration, recovering the neuromuscular functions in peripheral hyperalgesia and allodynia; and (3) methylcobalamin inhibited the ectopic spontaneous discharges from peripheral primary sensory neurons in neuropathic pain states. Methylcobalamin is the only form that can cross the blood-brain barrier and so can directly protect brain cells from degeneration. While crossing the barrier, it also stimulates production of serotonin, a chemical neurotransmitter responsible for elevated mood; research where Alzheimer’s patients were administered methylcobalamin showcased improvements in memory, communication skills, and emotions. It also helps form the myelin sheath, the insular coating around nerve cells that allow for electrical impulses to travel through the nervous system more efficiently.

Doconexent (Docosahexaenoic acid, DHA) is an omega-3 fatty acid that is a primary structural component of the human brain, cerebral cortex, skin, and retina. DHA is widely used as a food supplement, and is beleived to support healthy brain development in young childred, prevent cardiovascular disease and cognitive decline during Alzheimer's disease. Most of these claims, however, were not supported by clinical trials. DHA spray is used as a tanner.

Glucosamine is an amino sugar and a prominent precursor in the biochemical synthesis of glycosylated proteins and lipids. Glucosamine is part of the structure of the polysaccharides chitosan and chitin, which compose the exoskeletons of crustaceans and other arthropods, as well as the cell walls of fungi and many higher organisms. Glucosamine is one of the most abundant monosaccharides. It is produced commercially by the hydrolysis of crustacean exoskeletons or, less commonly, by fermentation of a grain such as corn or wheat. Oral glucosamine is a dietary supplement and is not a pharmaceutical drug. It is illegal in the US to market any dietary supplement as a treatment for any disease or condition. Glucosamine is marketed to support the structure and function of joints, and the marketing is targeted to people suffering from osteoarthritis. Commonly sold forms of glucosamine are glucosamine sulfate, glucosamine hydrochloride, and N-acetylglucosamine. Of the three commonly available forms of glucosamine, only glucosamine sulfate is given a "likely effective" rating for treating osteoarthritis. Glucosamine is often sold in combination with other supplements such as chondroitin sulfate and methylsulfonylmethane. Glucosamine, along with commonly used chondroitin, is not routinely prescribed to treat people who have symptomatic osteoarthritis of the knee, as there is insufficient evidence that this treatment is helpful. One clinical study over three years showed that glucosamine in doses of 1500 mg per day is safe to use. Glucosamine with or without chondroitin elevates the international normalized ratio (INR) in individuals who are taking the blood thinner, warfarin. It may also interfere with the efficacy of chemotherapy for treating cancer symptoms. Adverse effects may include stomach upset, constipation, diarrhea, headache, and rash. There are case reports of people who have chronic liver disease and a worsening of their condition with glucosamine supplementation. Glucosamine is naturally present in the shells of shellfish, animal bones, bone marrow, and fungi. D-Glucosamine is made naturally in the form of glucosamine-6-phosphate, and is the biochemical precursor of all nitrogen-containing sugars. Specifically in humans, glucosamine-6-phosphate is synthesized from fructose 6-phosphate and glutamine by glutamine—fructose-6-phosphate transaminase as the first step of the hexosamine biosynthesis pathway. The end-product of this pathway is uridine diphosphate N-acetylglucosamine (UDP-GlcNAc), which is then used for making glycosaminoglycans, proteoglycans, and glycolipids. As the formation of glucosamine-6-phosphate is the first step for the synthesis of these products, glucosamine may be important in regulating their production; however, the way that the hexosamine biosynthesis pathway is actually regulated, and whether this could be involved in contributing to human disease remains unclear.