L-Norpseudoephedrine is a psychostimulant drug of amphetamine family, first isolated from an Ephedra species. It is one of the two enantiomers of norpseudoephedrine, less potent that D-Norpseudoephedrine. L-Norpseudoephedrine is a norepinephrine and dopamine releasing agent, and has thermogenic and anorectic effect.

L-838,417 is a subtype-selective GABAA modulator, acting as a partial agonist at alpha2, alpha3 and alpha5 subtypes and an antagonist at the alpha1 subtype. L-838,417 displays anxiolytic effects in vivo and is used as a tool compound to study roles of GABAA subunits.

L-368,899 is a potent and selective oxytocin (OT) receptor antagonist, which was developed by Merc as a promising non peptide OT antagonist. However, this compound failed in clinical development; phase II, for the treatment of premature labour. Merck subsequently abandoned its non peptide OT antagonist program.

Levoglucose (L-glucose) is the stereoisomer of D-glucose. L-Glucose does not occur naturally in higher living organisms, but can be synthesized in the laboratory. L-Glucose is indistinguishable in taste from D-glucose, but cannot be used by living organisms as source of energy because it cannot be phosphorylated by hexokinase, the first enzyme in the glycolysis pathway. Levoglucose may be used as diagnostic aid. It has been investigated as a non-nutritive food sweetener. However, L-glucose produced significant laxation, with an average of 4 to 5 loose watery stools in a 24-hour period. This laxative property clearly reduced the use of L-glucose as a food additive. The mechanism of laxation after L-glucose ingestion is unknown, but malabsorption of the compound with secondary osmotic diarrhea is likely. L-glucose is a well-tolerated, safe, and efficacious means of cleansing the colon for colonoscopy. The L-glucose pentaacetate anomers could be used as novel insulinotropic tools in the treatment of non-insulin-dependent diabetes mellitus.

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.