Human evolution doesn't care about life after prehistoric child-rearing. It has no reason to optimise for longevity.

HGH has deleterious health effects when abused. But it can also make you a famous movie star living a life of luxury whose children will never have to work. Our personal goals have very different parameters to what defined our evolution.

There are also other things that the human body benefits from but can't make itself. Creatine, essential amino acids, essential minerals and vitamins.