Just wanted to give some input on OP’s “age aspect”.
Yes ideally everyone should wait as long as possible and have a good strength base and honestly look good natty (ie no more than legit 12% bf) in order to benefit the most from gear. However, for many people having all those things can take so long that they’re not gonna be able to make it happen in their 20s (look at the majority of natty gymgoers in their 20s lol. At the end of the day it’s big, lean, natty pick 2). If some dude wants to hop on gear for mostly vain purposes anyway (like 90%+ of us on this forum), they’re leaving a lot on the table by putting it off till their young years are simply gone and waiting till mid/late 30s. Doing gear is simply not the same when you’re younger and have fewer responsibilities than when you’re older and likely have a wife/kids and some demanding job and a mortgage
On the flipside, if a guy starts too young in their early 20s or so, they’ll likely have more lifetime exposure to high doses because 9/10 times they won’t have the maturity and foresight to use gear wisely, so actual acute health issues as well as other long term side effects could in fact manifest in their late 20s and early 30s, and this does indeed happen as we see irl. And the younger you are, even if you’re forced into cessation for some time, it’s highly likely you’ll use supranormal doses again later on. Either that or you’ll likely stop going to the gym entirely…or just go briefly for quick workouts just to maintain (the latter not a bad thing depending on stage of life)
Life’s full of choices…