What are B7-33 peptides? Peptides B7-33 is a functional selective Relaxin-receptor 1 agonist in development, derived from the naturally occurring human hormone Relaxin-2. Relaxin’s peptides are structurally similar to insulin-like peptides in that they consist of two chains of 53 amino acids, chain A and chain B, and connect the two chains  by three disulfide bonds to function. This chemical …