GHK-Cu has the strongest case here (topical skin data); collagen is a mild supplement signal. AOD-9604 and the GH-axis additions carry the physique claims, which are weakly evidenced.
With limited or no human safety data for this combination, there is no established marker set to monitor against — which is a reason for more caution, not less. Baseline bloods and a clinician conversation matter here. General information, not medical advice.