L-Carnosine is a white to slightly off-white crystalline powder that is used as a substrate for carnosinase-1 and other enzymes.

L-Cysteine is a non-animal-derived, sulfur containing proteinogenic amino acid that is important in the maintaining of normal iron levels in the body and plays a critical role in reducing oxidative damage and inflammation. While naturally produced by the human body, L-Cysteine can also be obtained through certain dietary sources. Research indicates that L-Cysteine is essential in regulating protein oxidation and cellular injury responses. Additionally, it contributes to immune function by interacting with Toll-like receptors, key proteins involved in inflammation and immune responses. L-Cysteine enhances immune defense by stimulating antibody production, essential for combating infections. As a key amino acid, L-Cysteine participates in various biochemical processes, including protein and DNA synthesis, and regulates gene expression through its influence on promoter response elements.

L-Fucose is a six-carbon deoxy monosaccharide that is equivalent to 6-deoxy-L-galactose. L-Fucose is found on many N- and O-linked glycans present on the cell surface of a wide variety of organisms. The most well-known fucosylated glycans are the ABO blood group antigens. L-fucose present in gastrointestinal mucous represses virulence factor-encoding genes expressed by enterohemorrhagic E. coli. Mutations in the gene that encodes alpha-L-fucosidase can cause fucosidosis, leading to a buildup of fucose-containing compounds which cause cellular malfunction.

L-Glutamic acid gamma-(7-amido-4-methylcoumarin) is a substrate for aminopeptidase A. In the gamma-glutamyl transferase assay, the substrate cleaves to yield a blue fluorescent solution.

L-Glutamic acid HCl is a water-soluble organic acid and monosodium salt. It plays a crucial role as a neurotransmitter within the central nervous system and serves as a significant biochemical precursor in the biosynthesis of proteins, peptides, and nucleic acids. In vitro studies have demonstrated that L-(+)-glutamic acid HCl induces apoptosis in human HL-60 cells by elevating reactive oxygen species (ROS) levels and activating caspase-3 activity. This compound is essential for various biochemical applications and research in cellular biology and neurochemistry.

Fluorogenic substrate for aminopeptidase A, yielding a blue fluorescent solution upon cleavage.

L-Glutathione is a co-substrate to glutathione transferase found in plants and animals and is involved in the elimination of free radicals resulting from both cellular respiratory and metabolic activities.

L-Gulono-gamma-lactone is the furanose form of gulonolactone. It is metabolized by L-gulonolactone oxidase with oxygen to produce L-xylo-hex-3-gulonolactone, which can convert hexuronic acid to ascorbic acid spontaneously. As a reagent L-gulonolactone forms the first step for the synthesis of deoxymannojirimycin and mannonolactam, an anti-HIV drug and a reagent for drug synthesis respectively.

L-Histidinol dihydrochloride is a histamine precursor. It has been shown to reversibly inhibit protein synthesis.

Homocysteine is a cysteine homolog,and only differs by having an additional methylene bridge. It is often used in vitro as a reference to measure L-homocysteine in plasma in order to diagnose homocystinuria. This genetic disorder causes the body to be unable to process certain amino acids.

Higher levels of homocysteine found in the body is due to having vitamin B6 or B12 deficiencies. Finding higher levels may indicate possible cardiovascular disease; however, reducing the levels of homocysteine in the body does not appear to remedy the situation.