Growth factors are proteins that are naturally produced by skin cells and responsible for maintaining homeostasis, which helps you keep your skin alive and healthy. In simpler terms, the purpose of growth factors is to act as a healing agent. The substance can help to “boost collagen synthesis, prompt cells to produce components that improve skin firmness and elasticity, strengthen the skin barrier and repair and rejuvenate skin’’.

The growth factors found in serums, gels, and creams are either bioengineered in a laboratory, or culled from human stem cells — but not necessarily human skin stem cells. Stem cells from any source — skin, fat, bone marrow, umbilical cord — can produce growth factors that give rise to a variety of different cell types in the body.

When growth factors are applied to the skin in high concentrations, a very small fraction of them interact with the topmost layers of the skin, and initiates a communication chain that leads to stimulation of dermal fibroblasts,” sparking collagen growth. The aforementioned 2009 Journal of Drugs in Dermatology study expands on the theory, but the science is super heavy, and the language explaining it, convoluted, so here’s the gist: Growth factor serums essentially urge the living cells of your skin’s surface layer to call down to collagen cells, Hey, pump out more growth factors! This order then incites swifter cell turnover and more robust growth-factor output, which then triggers more collagen creation down below the surface for glowier, plumper, prettier skin.