Peptides have several important functions: 

• They are precursors of proteins and are also the constituents of alkaloids. 
• Peptides act as hormones and growth factors and they also function as antioxidants, scavenging free radicals. 
• They possess antibacterial properties.
• They form long chains creating structural protein which provides the body with support.
• Hyper secretion of peptide in urine acts as an indicator for certain mental conditions such as schizophrenia and depression among others.