How do growth hormones reverse or delay aging?

No evidence of that: Hi. GH can help with muscle mass/lean body mass, skeletal health, sense of well being, etc in GH-deficient people. So that could make aging feel better and go smoother in GH-deficient people, but I think it's a marketing ploy to tell people GH reverses or delays aging, especially in people who are not GH-deficient. Live healthily!