Growth Factors in Healing

The growth factors of tissue repair are polypeptides released in sequence as a wound progresses: PDGF from platelet granules and macrophages recruiting fibroblasts, TGF-beta driving matrix deposition and myofibroblast differentiation, VEGF driving capillary sprouting, the FGF family supporting granulation, and EGF supporting epithelial migration. Two features dominate their pharmacology: they act locally at very short range, and their free half-lives in tissue are measured in minutes. Much of their activity comes from being tethered in the extracellular matrix and liberated gradually, so the signal is a gradient in space and time rather than a concentration.

That is precisely what an injected or topical bolus cannot reproduce, and the translational record reflects it. Becaplermin, a recombinant PDGF-BB gel, was approved in 1997 for diabetic foot ulcers with modest effect sizes and later acquired a boxed warning over cancer mortality. Platelet-rich plasma, marketed on its growth factor content, has been tested extensively; the RESTORE trial published in 2021 found intra-articular PRP no better than saline for knee osteoarthritis pain or cartilage volume over twelve months, consistent with much of the tendinopathy literature.

What this permits you to conclude is narrow. Growth factors are unambiguously necessary for healing, which is a statement about physiology. It does not follow that adding more accelerates anything, and in an unimpaired wound the endogenous signal is not the limiting step.

The claim to reject outright is that a product contains or stimulates growth factors, offered as though that were an outcome. For systemically marketed peptides claiming growth factor release, the relevant question is whether anything measurable changed at the injury site, which is almost never assessed.