superoxide dismutase and glutathione Concerted action of peroxidase-1, Catalase, Biotrade Glutathione + Sod (Superoxide

Doubling concentration doesn't double results

Blood pressure: GHK can mildly lower BP at high doses

One study found a significant reduction in hair loss over the span of four injection treatments, increasing the hair count from an average of 71 hair follicular units to 93

doi: 10.1128/JVI.79.2.1296-1307.2005 137 Williams PhDMCoxBLafuse PhDWArizaME

Because glutathione levels decrease as we age, some people turn to supplementation or eating a diet rich in whole foods, especially fruits and vegetables, to encourage the bodys production of this antioxidant

Slightly more nerdy answer: because peptides are small, they can bind directly to cell receptors and trigger specific biological effects