I am thinking that the reason the growth factors are not to be put on the skin after dermarolling or on an open wound it that they are produced from actual human tissue. Technically, all actual human elements are filtered out to create the growth factor serum, but I imagine there is always a slight chance that some small particles, or whatever, may evade filtering. It is my understanding that the growth factors media itself has no items that can be be "rejected" by another human immune system. But if there are some undetected particles, I suppose there could be some rejection reaction if the undesirable particle came into contact with the immune system. This is my own thinking, and nobody has actually said this, but it seems logical. Obviously, an open wound could present that problem, or even dermarolling. So, I think this is about avoiding any possible problem. Otherwise, I am sure they would call for injecting the growth factors under the skin for better healing, and that is definitely taboo.
I think that there are some methods where growth factors are developed from a patient's own tissue, and that would not pose the same type of problem.
Anyway, Skin Medica sells the TNS mainly to provide assistance in reducing and protecting from skin wrinkles, which the serum seems to be very good at helping fix, if one reads the reviews. In the case for dermarolling, I think the TNS serum may also have a positive effect on the outward skin texture that can be benificial. Acne cause all kinds of scars and messes with the skin texture. So, I am hoping it may provide some good effect on the outward portion of skin healing while the dermarolling helps with deveolpment of collagen beneath the skin level. I have also noticed that TNS provides a little skin tightening, which I think helps in itself, since I have a variety of scar types, including rolling scars, which seem to have a better appearance with tighter skin. It also gives a little bit of a shine, which I don't like. Also, the odor is pretty foul, but only last for a few minutes until it dries.
I have noticed some skin improvement for me in the last 6 weeks, and there are only three things that I can attribute it to- dermarolling (1 mm), retin-a, and TNS serum. I just recently also added a daily multiple vitamin. So, my plan is to stay on this track and see how things go.