What They Are
Growth factors are proteins through which cells send each other signals. Such a protein binds to a receptor on a cell surface and passes it an instruction, for example to produce more of a given substance or to divide.
In skin they take part in natural renewal processes. That is precisely what makes them interesting for cosmetics: the idea is that applied externally they might prompt the same processes. Whether that is what happens is a separate question.
Where they come from
In cosmetic products they are usually made biotechnologically: cell cultures or fermentation produce the protein, which is then purified. On an ingredient list they appear as EGF, FGF, IGF, or as “conditioned media”, meaning the medium cells were grown in.
The Central Problem: Size
Growth factors are large molecules. The skin barrier is built precisely to keep substances of that size out, and it generally does the job well.
That means much of what you apply stays on the surface. Manufacturers use various approaches to get around the limit, including encapsulation and smaller fragments of the molecule, but how well those work in real use remains an open question.
What the Research Shows
There are published studies reporting improvements in skin appearance and texture after using growth factor products. Most, however, are small, frequently lack a control group, and a substantial share were funded by the manufacturers of the products in question.
There is no large independent trial establishing a clear effect in cosmetic use. So the honest conclusion is that the category is promising but unproven, and its price runs ahead of the evidence for it.
The Safety Discussion
Because growth factors signal cells to divide, some specialists raise the question of whether prolonged use is entirely without concern. To date there is no data showing harm in cosmetic use.
Nor, however, are there long-term studies that answer the question definitively. If you have a history of skin disease or are undergoing treatment, discuss use with your doctor before adding such a product.
Are They Worth the Price
If your budget is limited, the answer is no. Money spent on retinol, vitamin C and good sun protection gives a more predictable result, because the evidence behind those ingredients is firmer.
If the basics are already in place and you want to add something on top, growth factors are a reasonable experiment provided your expectations are realistic. How the wider regime fits together is in our anti-ageing routine.
How to Use Them
In the evening, on clean skin, before a richer cream. Proteins are sensitive to heat and light, so packaging should be opaque and airtight, and cool storage is preferable.
Do not combine them with acids on the same evening: an acidic environment can break the protein down before it does anything at all. Alternate across evenings if you use both.
How to Read the Label
Designations such as sh-oligopeptide-1, sh-polypeptide-1 and similar indicate biotechnologically produced growth factors. The sh prefix stands for synthetic human, meaning made on a human model but by synthetic means.
Concentration is almost never declared, and the position on the ingredient list is often near the end. That is not in itself irregular, since proteins work in small amounts, but it does make comparing products difficult.
Which Promises Overreach
Claims about “repairing skin at the cellular level”, results comparable to a procedure, or reversing ageing go beyond what a cosmetic does. A cosmetic product improves how skin looks; it does not change structures below the surface.
The sensible way to judge such a product is by its whole formula. If alongside the growth factors it contains well-chosen humectants, antioxidants and barrier components, you will probably see a result - but it will not come from the most expensive ingredient on the label alone.
