Do you do anything to help it penetrate the skin? I thought it was too big to pass through?
EGF acts by binding with high affinity to epidermal growth factor receptor (EGFR) on the cell surface and stimulating the intrinsic protein-tyrosine kinase activity of the receptor. The tyrosine kinase activity, in turn, initiates a signal transduction cascade that results in a variety of biochemical changes within the cell - a rise in intracellular calcium levels, increased glycolysis and protein synthesis, and increases in the expression of certain genes including the gene for EGFR - that ultimately lead to DNA synthesis and cell proliferation.
Fallon JH, Seroogy KB, Loughlin SE, Morrison RS, Bradshaw RA, Knaver DJ, Cunningham DD (June 1984). "Epidermal growth factor immunoreactive material in the central nervous system: location and development". Science 224 (4653): 1107–9.
Abstract
Experimental studies in animals have demonstrated that the topical application of epidermal growth factor accelerates the rate of epidermal regeneration of partial-thickness wounds and second-degree burns. We conducted a prospective, randomized, double-blind clinical trial using skin-graft-donor sites to determine whether epidermal growth factor would accelerate the rate of epidermal regeneration in humans. Paired donor sites were created in 12 patients who required skin grafting for either burns or reconstructive surgery. One donor site from each patient was treated topically with silver sulfadiazine cream, and one was treated with silver sulfadiazine cream containing epidermal growth factor (10 micrograms per milliliter). The donor sites were photographed daily, and healing was measured with the use of planimetric analysis. The donor sites treated with silver sulfadiazine containing epidermal growth factor had an accelerated rate of epidermal regeneration in all 12 patients as compared with that in the paired donor sites treated with silver sulfadiazine alone.
Treatment with epidermal growth factor significantly decreased the average length of time to 25 percent and 50 percent healing by approximately one day and that to 75 percent and 100 percent healing by approximately 1.5 days (P less than 0.02). Histologic evaluation of punch-biopsy specimens taken from the centers of donor sites three days after the onset of healing supported these results.
We conclude that epidermal growth factor accelerates the rate of healing of partial-thickness skin wounds. Further studies are required to determine the clinical importance of this finding.
GL Brown, LB Nanney, J Griffen, AB Cramer, JM Yancey, LJ Curtsinger, L Holtzin, GS Schultz, MJ Jurkiewicz, and JB Lynch. Enhancement of wound healing by topical treatment with epidermal growth factor. NEJM. 321:76-79
Here is another interesting study
CONCLUSIONS: The application of a mixture of topical growth factors may stimulate the repair of facial photodamage resulting in new collagen formation, epidermal thickening and the clinical appearance of smoother skin with less visible wrinkling.
Richard E. Fitzpatrick; Elizabeth F. Rostan. Reversal of photodamage with topical growth factors: a pilot study. Journal of Cosmetic and Laser Therapy. 476-4180, (5), Issue 1:25 – 34.
And another
Results. A total of 78.6% of patients with photodamaged skin showed clinical improvement at 60 days. New collagen formation increased by 37%, and epidermal thickening increased by 27%.
Fitzpatrick Richard E., MD. Endogenous Growth Factors as Cosmeceuticals. Dermatologic Surgery.(31) Issue s1:827 - 831.