l arginine or l carnitine which is better Amino Acids Complex Rexdrive® Amino with L-Arginine HCl,

& Wegrzyn, G

Health 19, 92

The Bottom Line Both TRT and GHS peptides can improve muscle mass, bone density, body composition, and lipid profiles, all of which decline with age

Inflammatory bowel disease increases the risk of Parkinsons disease: a Danish nationwide cohort study 19772014

This may be due to copper's ability to enhance the expression of metalloproteinases (MMPs).16 MMPs normally regulate the degradation of collagen, and a specific one, MMP-1, may be responsible for the initiation of collagen fragmentation.17 Supporting this, a 2024 study noted that elevated MMP-1 levels appear to contribute to aging skin and that higher MMP-1 levels in mice led to:18 The loss and fragmentation of dermal collagen fibrils Contracted fibroblast morphology Reduced collagen production Increased expression of pro-inflammatory mediators Additionally, a 2016 study found that GHK-Cu significantly increased gene expression of MMP-1 and MMP-2 at the lowest concentration, which the studys authors considered to be one of the reasons the peptide was able to increase collagen and elastin production.19 So, what this could ultimately mean is that using too much GHK-Cu (or other copper peptides) may in theory increase the skins MMP-1 concentration above the levels involved in healthy collagen production, taking it into the collagen fragmentation and breakdown territory seen in older skin with naturally higher MMP-1 levels

PMID 7936021