The Truth About Growth Factors: Part 1

If you’ve ever wondered what growth factors like EGF are, how they work in our skin, their research as far as skin and hair rejuvenation, or just whether they’re worth adding to your regimen – this one is for you.

We’re starting the long awaited growth factor deep dive and I’m so excited to dive into the science on this one with you all!

Part 1 will cover the science on this topic including what growth factors are, how they work in the skin, and what the evidence says in terms of their influence on the skin applied topically. We will also be clearing up some of the confusion and misinformation around this topic (like why these products do not have stem cells in them).

Part 2 will cover the more practical side. We’ll discuss formulation and what to look for, penetration and the necessity of delivery systems, my recommendations, how to incorporate growth factors into your routine, and the best treatments to pair them with. If you find the science a little dry, hang in there for the next part.

Lastly, this has been timed to go up alongside a video by my wonderful friend and fellow content creator Aging Naturally with Jodylynn! I had really fun time being interviewed by her on all things growth factors and I hope you’ll check out her channel too.

Watch the growth factor video here.


First off, what the heck is growth factor? You’ve probably heard the term often in skincare, especially with the hype around EGF in particular. Some of you may even be wondering how stem cells fit in. There’s actually a lot of confusion around what they even are.

In defining them, it’s helpful to think of “growth factor” as more of a description or job role rather than a specific type of cell or protein. The reason I say this is because while growth factors have become interchangeable with signaling peptides called cytokines, not all cytokines are growth factors – just the ones that influence cell growth and proliferation. And while growth factors are most often peptides, steroid hormones like estrogen can be too.

A growth factor is a biologically active molecule that is secreted by cells and able to influence cell growth as well as differentation. Most of them interact with surface receptors on cells which then sends a growth signal and evokes a cellular response – something called cell signalling or signal transduction. There are a few exceptions though like TGF-beta and steroid hormones which communicate a little differently.

Growth factors are present all over the body and serve a vital role, influencing all cell processes related to growth. Wound healing in particular is a wonderful example of growth factors at work – the second the skin is breached, skin cells called keratinocytes release prestored interleukin-1. This is what triggers the wound healing cascade and secreted growth factors are involved in each step.

The wound healing cascade is also a great example of how growth factors work. Each growth factor has a specific task and they work together to achieve the final result. A single growth factor is largely useless but together they can heal wounds or maintain skin health. We also have pro inflammatory and anti inflammatory growth factors – with the latter helping regulate the inflammatory response. Just remember that inflammatory processes are actually essential and not inherently bad.

Having covered how growth factors can vary in type, let’s discuss how we categorize them.

Growth Factor Families

Growth factors are primarily categorized by their structure and function as well as which receptors they bind to and which cell processes they’re involved in. These groups are typically referred to as “families.”

There are many different growth factor families and breaking them all down would not only take all day but would be needlessly confusing. So I’m just touching on the main ones that relate to our skin.

If you’ve heard terms like EGF or TGF tossed around, you may not have realized that there’s actually several different types. While I’ll be covering some of their common roles in terms of the skin, just rememember that I’m covering the broad strokes. Their role can change depending on the place in the body and the process.

The EGF Family plays a big role in maintaining and protecting our skin. Their name, Epidermal Growth Factor, lets us know they influence epidermal skin cells like keratinocytes.

The FGF Family and its Fibroblast Growth Factors also tells us a lot with its name as well. They target the fibroblasts in the dermis, stimulating them so that they produce more collagen.

PDGF is involved in angiogenesis (blood vessel formation) but also works hand in hand with EGF and TGF-beta during wound healing. TGF-b, on the other hand, is the regulator of the extracellar matrix in the dermis. Especially when it comes to collagen.

Now that you hopefully have a basic understanding of what growth factors are and how they work in the skin, let’s finish Part 1 by discussing what you’re really here for – topical growth factors in skincare.

Growth Factors in Skincare

It’s important to understand that just because something exists in the skin, doesn’t mean that it will be effective applied topically.

Both collagen and hyaluronic acid are components of our skin but their use in skincare is solely as humectants. They don’t make the skin produce more or have any anti aging effects. Similarly, just because something is wound healing doesn’t mean it can improve aged skin.

Like the skin identical ingredients I just touched on, growth factors are typically too large to pass through the skin barrier. Luckily, growth factors appear to be able to influence cells even applied topically and may even be able to penetrate regardless via the hair follicles. And most importantly, research looking at whether they improve wound healing has expanded to look at their use for skin and hair rejuvenation as well as combined with skin treatments like microneedling.

Think about it. There’s potential here for a topical product to influence skin regeneration and repair. And that’s without even getting into combining with treatments like microneedling that work via micro injury.

Stem Cell Conditioned Media

It’s important to stress that the research almost all involves stem cell conditioned media (SC-CM). Think of it like a ”growth factor soup” if that helps you visualize it. All of our skin cells can secrete growth factors – as can most other cells – and they replicate this outside the body by culturing the stem cells in a growth medium and removing them, leaving you with something called ”secretome.” The SC-CM you’re left with contains an array of growth factors like our skin as well as exosomes, microvessicles, and more.

Synthetic Growth Factors
Most people are more familiar with Epidermal Growth Factor (EGF) serums where it’s just a single growth factor or perhaps paired with a few other growth factors or peptides. These will be synthetic rather than being a product of donated human cells.

EGF is often synthesized via bacterial fermentation. You’ll typically see it listed on the ingredient deck as sh-Oligopeptide-1 or rh-Oligopeptide-1. The “sh” stands for synthetic human while ”rh” is recombinant human. The prefix doesn’t matter too much as all EGF is synthetic and made via gene recombination to my knowledge.

The issue with EGF alone is 1) the evidence isn’t as robust for skin rejuvenation outside of wound healing and 2) we know that growth factors are team players and work together so a single growth factor alone doesn’t make practical sense barring further studies.

There have also been concerns raised over whether EGF alone may disrupt the balance of the skin and its cell processes. For this reason, I would look for SC-CM whenever possible – but we will discuss this further in the second post.

Common Myths

Let’s wrap this up debunking some myths or misinformation I see on this topic and then finish with the evidence.

1. There are stem cells in growth factor products products

False. Stem cells aren’t stable in cosmetics, aren’t proven topically, and if you’re not a match to the donor issues could arise. Once they’ve secreted the growth factors we want, they’re removed.

2. Growth factors are useless without a delivery system or microneedling

False. The evidence just doesn’t show this, topical studies have still yielded results. The theory is that their topical application can still influence cell processes and they may utilize other routes to get into the skin like hair follicles. Delivery systems also still need more research and may not worked as advertised. Microneedling on the other hand does enhance results – but this is both due to penetration and the additional growth factors enhancing the treatment itself. That isn’t to say you can’t use something like AnteAge for peace of mind, just that it isn’t as clear cut as you might think.

3. Growth factors cause cancer

False. While EGF and other grow factors stimuate cell growth, they’re not mutagenic. Stem cell conditioned media has been studied in the medical field for years before we began using it for aesthetic treatments and in skincare as well and has been shown to be safe. If you have a history of skin cancer though I would discuss usage with your doctor first as we don’t know enough there yet. As well as going with a brand like AnteAge that has oncology testing.

4. Inflammatory cytokines are bad

Depending on which stem cells you culture, your stem cell conditioned media will vary slightly in terms of its composition. Bone marrow derived mesenchymal stem cell conditioned media (like the AnteAge as well as my favorite Bradceuticals) has a higher concentration of growth factors as well as more of the anti inflammatory ones. I recommend it though because it’s more studied than adipose SC-CM but that isn’t to say the latter doesn’t still have research conducted. Inflammatory molecules serve important roles like you saw in the GF families and they’re balanced by anti inflammatory ones regardless.

Have more myths or questions? Just comment below.


So let’s talk evidence because that’s always the important part for me (and many of you). We will be discussing who should use these and how in the second half of this 2 part post but I do want to stress that these are never a substitute for proven topicals like tretinoin and sunscreen. These are an add-on to a routine or they can enhance treatments like microneedling and laser.

To keep this brief, I will include a summary of the evidence ane then then link further research for those who want to research further themselves. Otherwise skip ahead ahead to the end if this part isn’t of interest:

  1. In terms of skin, the research suggests that growth factors are an effective anti aging therapy that help repair and rejuvenate the skin. They improve proliferation and differentation in the epidermis and may even act on dermal fibroblasts for more collagen deposition.
  2. Their wound healing ability also makes them excellent post treatment after microneedling and laser as well as applied to healing skin. Newer promising research is also finding that they can be beneficial for inflammatory skin disorders as well.
  3. They are gaining popularity in terms of hair loss, showing results on studies on both men and women. They also work well in conjunction with other proven therapies like Minoxidil and microneedling.
  4. There are limitations on the research as we need more long term studies and more clear research on different conditioned media types. More standardization in terms of how we culture the stem cells is vital.

Further Reading

That finishes this first part and I hope you enjoye it. In Part 2, we will be continuing our dive into this topic by looking at which SC-CM is best, formulation questions like which ingredients work well with growth factors, using them with your skin treatments and tools, product recommendations, and so much more.

Stay tuned and don’t forget to watch the video!

Aging Naturally with Jodylynn

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6 responses to “The Truth About Growth Factors: Part 1”

  1. Great information! So, if using bone marrow derived mesenchymal stem cell conditioned media (like Bradceuticals), is that enough to use alone to get EGF or would you use Bradceuticals and add EGF serum in combination?
    Thank you

    Liked by 1 person

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