Fibroblast growth factor 5 (FGF5) is a secreted signaling protein. FGF5 is expressed in the mesenchyme and skeletal muscle of developing and adult mouse limbs. FGF5 acts as a mitogen to stimulate the proliferation of mesenchymal fibroblasts that contribute to the formation of connective tissues such as the perichondrium, and inhibits the development of differentiated skeletal muscle. Fibroblast growth factor 5 (FGF5) regulates hair length in humans and a variety of other animals. Human aortic endothelial cells (HAECs) have greater angiogenic potential through FGF2 and FGF5 upregulation and could be a compatible endothelial cell type to achieve robust angiogenesis.