Peptides are small proteins that are made up of short chains of amino acids. There are several thousands of them, and they play varying roles in the body. Peptide therapy is an exciting new frontier in medicine that can be used to safely reverse disease, enhance lovemaking, decelerate the aging process, and make getting older a whole lot more pleasant. Certain peptides also play a central role in the immune system, and may even offer us a solution for COVID-19. MIT chemists are currently working on developing a 23-amino acid peptide that can block coronaviruses’ ability to enter human cells.