People need to stop talking in absolutes like this. It literally depends on the individual's biology.
If a 21 year old has low GH production and poor receptor sensitivity - for whatever reason - then it's going to help.
How many young cunts do you see with low test and whatnot? Why is it that GH/IGF-1 is always considered to be optimal in all youth at all times?
Biology has nothing to do with IGF 1 production levels. Its about diet and activity levels in the body that the body can actually create something that the body needs to recover from said activity. At 21 23 you’re in peak ranges of literally everything if your eating right and active. Point blank period. A secretagogue will do nothing for an active 21 year old.