Glycylglycine (Gly-Gly) is a dipeptide used in biochemical research. It is the simplest of all dipeptides and is used as a starting template for preparation of more complex peptides. Glycine is involved in the body's production of DNA phospholipids and collagen and in the release of energy.

Eptifibatide an antiplatelet drug of the glycoprotein IIb/IIIa inhibitor class is a cyclic heptapeptide constructed from 6 amino acids and a mercaptopropionyl residue.

[Sar1, Ile8]-Angiotensin II is a peptide that has multiple effects on vascular smooth muscle, including contraction of normal arteries and hypertrophy or hyperplasia of cultured cells or diseased vessels. The biological activities of angiotensin II antagonists upon basal and angiotensin II-stimulated aldosterone production were evaluated in an isolated canine glomerulosa cell preparation.