Sh-Polypeptide-9 is a cell signaling protein also called Vascular Endothelial Growth Factor. As its name suggests, its main function is to stimulate the formation of blood vessels. As to what it does in cosmetic products, we found manufacturers info claiming that it plays a role in supplying fibroblast cells (VIP skin cells that make collagen) with nutrients, in the growth and migration of cells and in wound healing.
It usually comes to the formula as part of a Growth Factor mix trade named BIO-Placenta, that combines EGF, IGF-1, FGF1, FGF2 and this guy to form a synergistic growth factor cocktail. BIO Placenta is claimed to do pretty much everything you would want from an anti-aging active including anti-wrinkle, skin rejuvenation, elasticity enhancement, moisturizing and cell vitalization properties.
This all sounds great and Growth Factors are for sure potent cell signaling molecules, but the use of them in cosmetic products is somewhat controversial, so if you are new to the topic, read our explanation at EGF to get a (hopefully) balanced view.