For hair restoration specifically, some protocols combine subcutaneous GHK-Cu with direct scalp injection (mesotherapy) to deliver the peptide closer to the follicle bulb
But this has been steady since 2018
PubMed Kim, S.B., Kwon, D.R., Kwak, H., Shin, Y.B., Han, H.J., Lee, J.H., & Choi, S.H
The standard redox potential of cysteinecystine from the thioldisulphide exchange reaction with glutathione and lipoic acid
Pozeg, Z
Precursor Conversion Process : Unlike direct glutathione supplementation, this phenylacetylated form functions as a prodrug that requires enzymatic activation within cells, ensuring glutathione is generated precisely where cellular health supplements can provide maximum benefit