Dipeptide- Carnosine, anserine, aspartame
Tripepeptide- Glutathione, TRH
Pentapeptide - Encephalins
Octapeptides- Angiotensin II
Nanopeptides- Vasopressin, Oxytocin, Bradykinin
Decapeptide- Kallidin, Angiotensin I

Other- Gastrin, secretin
Antibiotics- Bacitracin, actinomycin, gramicidin