Iv got a few questions id like clearing up regarding HGH...

Is it worthless if used under 30 years old ?
Does it make the heart more efficient ?
Is it good for the heart ?
Is it good or does it improve any other organs in the body ?
Is it true it can make you live longer ?
Is it worthless unless used for a longer period of time like 6 months ?
Can it improve your physical fitness ?