2-Methylhippuric acid is a derivative of hippuric acid. It is found in the urine of individuals infected with the hepatitis B virus, determined using HPLC.

4-Methylhippuric acid is has been used as a biological marker to monitor xylene exposure. It can also be used in HPLC to determine the carboxylic acid concentration in urine, along with styrene and ethyl benzene.

5-Fluoro-DL-tryptophan is a fluorinated tryptophan analog that is capable of being incorporated into proteins. It may be incorporated into cyclic AMP receptor protein (CRP) to study ligand binding changes in E. coli. Additionally, it can serve as an internal standard in chromogenic analysis of tryptophan and other tryptophan derivatives. Metabolically, 5-fluoro-DL-tryptophan is a tryptophan antagonist.

5-Fluoro-L-tryptophan monohydrate is a tryptophan derivative incorporated into proteins during their synthesis. It is useful as a reporter group due 19F and provides a way to study enzyme mechanisms through NMR. 5-fluoro-L-tryptophan is nonspecifically cytotoxic due to malfunctioning enzymes containing 5-fluoro-Trp in place of Trp.

5-Nitro-DL-tryptophan is a tryptophan derivative commonly used in biochemical research applications.

Leucine is an alpha-amino acid used in the biosynthesis of proteins that is not synthesized by animals and must be ingested. Leucine is an activator of mTOR, stimulating muscle protein synthesis. Leucine is also used in hemoglobin formation.

D-Leucine has been used to protect mice from seizures and D-leucine specifically terminates seizures in mice after in the onset of seizure activity, while in breast cancers it can inhibit system L(LAT1) based growth. D-Leucine also triggers the disassembly of amyloid fibers linking biofilms.

D-lysine is an alpha amino acid. D-lysine based polyamino acids help cells and proteins attach to solid surfaces, and the D conformation useful in promoting adhesion to solid substrates. Poly-D-lysine based hydrogels have been used for traumatic brain injuries. Crystal structures based on chiral PNA-DNA duplexes with d-lysine are also observed.

D-Norvaline is an alpha-amino acid. It is a natural component of an antifungal peptide of Bacillus subtilis, and may be part of the production of cell walls resistant to vancomycin. As a reagent it has been used to synthesize MMP inhibitors.