When I first heard about human growth factors in skin care creams, I, like Cosmetics Cop Paula Begoun, was skeptical. It sounded like an attempt for the skincare industry to prematurely incorporate a fancy scientific term into creams to make big sales. However, I was wrong. There seems to be promise in using specific human growth factors and certain cytokines in conjunction to enhance wound healing following dermatological treatments with lasers or dermatologic surgery, reduce wrinkling, and increase skin smoothness. However, please note that I said promise, not proof: most of the studies are from just earlier this year, and are not double-blind or placebo-controlled, so more work needs to be done before certain human growth factors and certain cytokines are universally accepted as potent anti-aging ingredients.
How do human growth factors work?
Although the exact mechanism is not known, it has been proposed in the Journal of Drugs in Dermatology that topically-applied human growth factors may be beneficial in reducing signs of skin aging due to their capacity in promoting dermal fibroblast and keratinocyte proliferation, and in inducing extracellular matrix formation, including collagens.
What is the difference between human growth factors and cytokines? Do both need to be present in skincare for it to be effective?
According to scientists at Indiana State, growth factors are proteins that bind to receptors on the cell surface, with the primary result of activating cellular proliferation and/or differentiation. Many growth factors are quite versatile, stimulating cellular division in numerous different cell types; while others are specific to a particular cell-type. Cytokines are a unique family of growth factors that are secreted primarily from leukocytes. Cytokines primarily stimulate immune responses, and some cytokines can activate specific types of cellular proliferation and/or differentiation as a result.
At this time, according to the 2007 study in the Journal of Drugs in Dermatology, no studies have been published comparing the effects of topically-applied creams containing all human growth factors versus those containing only cytokines.
Are all human growth factors the same?
No. According to Dr. Neil Sadick, human growth factors (HGFs) might be derived from a number of different tissue sources, and each of these HGFs has particular biologic characteristics which have a role in cellular modulation.
According to Dr. Sadick, basic fibroblast growth factor, vascular endothelial growth factor and hepatocyte growth factor stimulate new blood vessel formation; keratinocyte growth factor stimulates epithelial cell growth; insulin-like growth factor 1 promotes new cell growth and multiplication; and platelet-derived growth factor AA regulates cell growth and division.
Do all cytokines have different effects too?
Cytokines all stimulate immune responses, but different cytokines can stimulate different cells. Interleukins are cytokines that are secreted by white blood cells. According to at least one study, interleukins IL-6, IL-7 and IL-8 reduce inflammation in the skin. According to the study, transforming growth factor beta (TGF-ß) can stimulate collagen production, a claim which is affirmed by Dr. Neil Sadick: “Transforming growth factor ß l (TGF-ßl) is felt to be one of great importance in that it is a profibrotic cytokine, which modulates various aspects of dermal remodeling including neocollagenesis [the synthesis of new collagen fibers].” A 1990 study by Beck et. al., amongst other studies, further affirms that topical application of TGF-ß1 can enhance the healing of skin wounds.
What are some products that contain human growth factors and cytokines? Are they proven effective?
One product that contains human growth factors and cytokines is SkinMedica TNS Recovery Complex ($116.10, Amazon.com). SkinMedica TNS Recovery Complex contains a complex called Nouricel MD, which contains all of the human growth factors and cytokines listed in bold above. According to the company, “NouriCel-MD is the first ingredient derived from the manufacture of bioengineered human skin which contains an array of natural human growth factors and other compounds produced by healthy new skin.” Sadick affirms that, “Recent studies have documented that by utilizing topical HGFs extracted from bioengineered skin, one can improve photodamaged skin.” Unfortunately, SkinMedica TNS Recovery Complex also contains collagen, which is too large to pass through the epidermis to get to the collagen-containing layers underneath. As a result, this is a useless ingredient.
A second product that contains human growth factors and cytokines is Bio-Restorative Skin Cream ($72.00, Amazon.com) which contains a human growth factor and cytokine mixture called PSP (“Processed Skin Cell Proteins”) originally derived from fetal fibroblasts (not bioengineered skin, as in SkinMedica TNS Recovery Complex). Neocutis, the company that makes Bio-Restorative Skin Cream, is quick to point out that the fetal fibroblasts were only used in the original culture, have since been sustained. However, it is still safe to surmise that the original use of fetal fibroblasts is probably the reason SkinMedica TNS Recovery Complex gains more publicity.
In a 2007 study in the Journal of Drugs in Dermatology, subjects used Neocutis’ Bio-Restorative Skin Cream on half of their face for sixty days. After the 60-day period, 83% of the subjects showed an improved average wrinkle score in the eye area, while 50% showed an improved average wrinkle score in the mouth area. However, the study was not double-blind or placebo-controlled. In addition, no studies have been conducted comparing Neocutis’ Bio-Restorative Skin Cream (derived from an original culture of fetal fibroblasts) to SkinMedica TNS Recovery Complex (derived from bioengineered skin), nor have the concentrations of human growth factors and cytokines necessary for maximal results been determined. Although the 1990 study by Beck et. al. demonstrated that 250 ng rh-TGFß1 but not 25 ng rh-TGFß1 exhibited a healing effect, neither company publishes the amount of any of their human growth factors or cytokines in their products.
So: to buy or not to buy?
Research on human growth factors and the skin is clearly a work in progress. SkinMedica TNS Recovery Complex ($116.10, Amazon.com) reveals the specific human growth factors and cytokines present (in bold above), which is useful information. Despite my best efforts, I could not find the specific human growth factors and cytokines present in Neocutis’ Bio-Restorative Skin Cream ($72.00, Amazon.com).
If I were extremely curious and had to select one of the two, I would select the SkinMedica TNS Recovery Complex ($116.10, Amazon.com). However, these products may be a better buy after a few years, after the effects of human growth factors and cytokines are reliably established and quantitatively compared to well-known anti-aging ingredients like retinoids, antioxidants, hydroquinone or niacinamide.
Product rating (SkinMedica TNS Recovery Complex ($116.10, Amazon.com)): 8.5/10. Looks promising so far, but expensive, and hardly any published double-blind placebo-controlled independent research studies proving the effectiveness of its ingredients.