IGF-1/HGH is directly correlated to skin aging (wrinkles) and also body composition (Muscle/body fat levels), joint health/strength, cognitive function etc.
We get wrinkles as we age, gain body fat, lose muscle, and lose memory cognitive function and this is in big part due to the drop in IGF-1 and HGH. You heard the saying "black never cracks", people of african descent tend to have higher IGF-1/HGH levels and estradiol levels. This keeps the skin "younger" for longer.
You know when you are younger and can eat like crazy and not gain any fat? (for some people) That's the effect of pubertal levels of HGH. We see a sharp decreased starting around the third decades (30's) and that's kind of when your body starts going to shit.
IGF-1/HGH is also cardioprotective and anti-atherosclerosis. You see more heart disease with as our sex hormones and IGF-1/HGH decrease with age.
There are also theories that the lower risk of cancer in youth is actually thanks to high HGH/IGF-1 as they significantly maintain optimal thymus/immune function. A strong immune system keeps cancer/mutated cells from replicating and spreading. As we age, low HGH/IGF-1 = smaller thymus = weak immune system = you die from cancer or common cold/flu more easily. (This is one theory from a study investigating why covid-19 was only fatal in mostly aged persons ; they linked it to HGH levels in their hypothesis)