The safer way to frame the question is: if a licensed clinician has prescribed a subcutaneous medication and trained you on technique, what areas are commonly used and what should be avoided
1994 Dec;8(15):1302-7
Pickart stated that GHK-Cu has a favorable safety profile, highlighting that there is no indication that it causes side effects in test subjects [2]: The molecule is very safe and no issues have ever arisen during its use as a skin cosmetic or in human wound healing studies. In a 2018 review based on new genetic data, he reiterated that all biological actions associated with GHK appear to be health positive. He pointed to over four decades of GHK research encompassing cell, tissue, and animal studies, also noting the peptides inclusion in commercial anti-aging and cosmetic products such as creams, liposomes, and dermal patches [1]
The calibration curve was linear, with a correlation coefficient of 0.99223
[DOI] [PubMed] [Google Scholar] [13].Hinson JA, Monks TJ, Hong M, Highet RJ, Pohl LR
Correlation between the human fecal microbiota and depression
