When I was into body building but constrained by being an obvious "hard gainer" I tried lots of training and nutrition ideas, the one diet that seemed to pay off was what one guy described to me as the "all red meat" diet. No you don't only eat red meat, but you try to consciously consume as much as you can. Steak for breakfast with eggs, hamburger for lunch, even eat a big steak right before you go to bed as as long as it's not too many calories for your body to use soon it won't convert to fat.
You also have to break out if the mold of thinking whatever the big guy in the gym does will help me. Find a guy who looked like you a few months ago and is now noticeably bigger.
In those days I trained at Gold's Gym in San Diego right next to Achim Albricht, Sonny Schmidt, Big Jim Quinn and Milos Sarcev. It was quite obvious these guys were both genetic freaks and on steroids, I remember one of the more candid trainers speaking about them and Dorian Yates in particular, saying Dorian could push a broom all day and not look much different than he did then.
What they were doing and eating had little relevance toward most of the rest of us. The biggest scam was Weider magazine's constant use of endorsements by pros for advertisers selling protein powder and the like, one month Milos appeared in an ad proudly showing him holding this outrageously expensive, horrible tasting powdered cardboard and dirt mixture (tastes that way at least) and he laughed at the fat check he was paid and word around the gym was he had used it just once after they comped him some as part of the contract and he spit it out after tasting it.
The ad made it sound like all his muscle came from using that product.
I did find the Arnold Schwarzeneggar encyclopedia of bodybuilding to be a reliable and helpful reference. Weider's rags are best used for puppy training, fully useless and most of the "expert" famous columnists are egotistical dopes arguing their way is best, silly for the above explained reasons.
(I was once confident I would be into bodybuilding until death. That ended one day when I was doing incline press on a smith rack, felt strong that day, threw an extra ten on each side going for six. On the third rep I turned my head left to look at the mirror and check my form and heard a pop, lucky the smith rack caught the bar for me. I don't know what I injured but it was moderately painful, and I could never pick up a 45 plate without almost dropping it from the pain. Kept trying to go back and train for two years but it persisted. Today 15 years later I have severe scoliosis, possibly related?)
The most commonly used AAS in medicine are testosterone and its various esters (but most commonly testosterone undecanoate , testosterone enanthate , testosterone cypionate , and testosterone propionate ),  nandrolone esters (most commonly nandrolone decanoate and nandrolone phenylpropionate ), stanozolol , and metandienone (methandrostenolone).  Others also available and used commonly but to a lesser extent include methyltestosterone , oxandrolone , mesterolone , and oxymetholone , as well as drostanolone propionate , metenolone (methylandrostenolone), and fluoxymesterone .  Dihydrotestosterone (DHT; androstanolone, stanolone) and its esters are also notable, although they are not widely used in medicine.  Boldenone undecylenate and trenbolone acetate are used in veterinary medicine .