Calcitonin gene related peptide (CGRP) is a member of the calcitonin family of peptides which in humans exists in two forms α-CGRP and β-CGRP. α-CGRP is a 37-amino acid peptide and is formed from the alternative splicing of the calcitonin/CGRP gene located on chromosome 11. The less-studied β-CGRP differs in three amino acids (in humans) and is encoded in a separate gene in the same vicinity.