GHK-Cu vs NAD+: Which One Stings More?

For anyone who has tried both GHK-Cu and NAD+, what differences did you notice between them?

I’m mainly curious about the injection-site feel. Does NAD+ sting more for you than GHK-Cu, or is it just me?

Also curious what effects people personally noticed from each one — energy, recovery, skin, inflammation, mood, or anything else.

Experience only — not medical advice.