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Overview NADH (reduced nicotinamide adenine dinucleotide) is the active, electron-carrying form of NAD+. It is the primary electron donor in mitochondrial oxidative phosphorylation and participates in hundreds of metabolic reactions — most critically in the citric acid cycle and the electron…
13 May 2026
Overview Folate is a water-soluble B vitamin (B9) essential for one-carbon metabolism — the biochemical foundation of DNA synthesis, DNA repair, methylation reactions, and amino acid interconversions. The term "folate" covers all biologically active forms; folic acid is the synthetic oxidized…
13 May 2026
Overview S-adenosylmethionine (SAMe) is a naturally occurring molecule synthesized in every cell from methionine and ATP. It is the primary methyl-group donor in human biochemistry, participating in over 200 enzymatic reactions — methylating DNA, RNA, proteins, phospholipids, and…
13 May 2026
Overview Pyrroloquinoline quinone (PQQ) is a redox-active quinone compound found in trace amounts in many foods (especially natto, green peppers, kiwi, and breast milk) and in soil bacteria. It was identified as a bacterial cofactor for some oxidoreductases and was initially proposed as a…
13 May 2026
Overview Para-aminobenzoic acid (PABA) is an organic compound that was once considered a B vitamin (sometimes labeled vitamin Bx) but is no longer classified as a vitamin because it has no defined essential function in human metabolism that cannot be met by other means. PABA is a precursor to…
13 May 2026
Overview Vitamin B12 (cobalamin) is a water-soluble B vitamin and the largest, most structurally complex of all vitamins. It is the only vitamin containing a metal ion (cobalt), hence its chemical name. B12 is essential for DNA synthesis, myelin formation, red blood cell maturation, and…
13 May 2026
Overview Vitamin A is a fat-soluble micronutrient essential for vision, immune function, cellular differentiation, and reproductive health. The term "Vitamin A" encompasses a family of structurally related compounds: preformed vitamin A (retinol, retinyl esters, retinoic acid — found in animal…
13 May 2026
Overview Calcium is the most abundant mineral in the human body, with roughly 99% stored in bone and teeth and 1% circulating in serum, intracellular fluid, and soft tissues. It is essential for skeletal integrity, neuromuscular function, cardiac rhythmicity, vascular smooth-muscle tone…
13 May 2026
Overview Vitamin K1 (phylloquinone) is the primary dietary form of vitamin K, synthesized by plants and found abundantly in leafy green vegetables. It is distinct from vitamin K2 (menaquinones), which is covered in a separate monograph. Vitamin K is essential for the carboxylation of glutamate…
13 May 2026
Overview Vitamin E is a family of eight fat-soluble antioxidant compounds: four tocopherols (alpha, beta, gamma, delta) and four tocotrienols (alpha, beta, gamma, delta). Alpha-tocopherol is the most biologically active form in humans and the primary form measured in serum. It is the only form…
13 May 2026
Overview Iodine is an essential trace element required exclusively for the synthesis of thyroid hormones—thyroxine (T4) and triiodothyronine (T3)—which regulate metabolic rate, thermogenesis, cardiac output, neurological development, and nearly every organ system. Iodine deficiency is the…
13 May 2026
Overview Copper is an essential trace mineral and catalytic cofactor for more than 30 enzymes involved in energy metabolism, iron homeostasis, antioxidant defense, connective-tissue synthesis, neurotransmitter production, and immune function. Though required in small amounts (RDA ~0.9 mg/day)…
13 May 2026
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