There's no requirement to separate them by a specific number of hours, but using different injection sites is standard practice
(PubMed) Meydani SN, Meydani M, Blumberg JB, et al
Alternative Therapies in Health and Medicine , 27 (4), 813
Our guide detailing the best copper peptide serums is a great place to start
The primary antibodies used included anti-ZO-1 (Abcam, ab307799, 1:5000), anti-Occludin (Abcam, ab216327, 1:5000), anti-ACSL4 (Abcam, ab155282, 1:10000), anti-TFR1 (ABclonal, A5865, 1:2000), anti-SLC7 A11 (Abcam, ab175186, 1:5000), anti-GPX4 (Abcam, ab125066, 1:5000), anti-VDAC2 (Proteintech, 116631-AP, 1:5000), anti-VDAC3 (Proteintech, 552601-AP, 1:5000), -tubulin (Proteintech, 100681-AP, 1:5000), and GAPDH (Proteintech, 104941-AP, 1:20000)
Ideal candidates include adults interested in evidence-based longevity interventions, individuals seeking to optimize healthspan and biological age, patients with family histories of age-related disease, and those committed to comprehensive preventive health strategies