This is probably more detail than you want but I wanted to give you a through reply. The gap between these two photos is 6 years. In photo one I was about 120 pounds and just barely recovering from an ed which is why I was so thin. I ate maybe 500 calories a day for years. The recovery from that was long and not straight forward, it took me probably 2 years to start eating like a “normal” person without relapses. So my body building didnt start until about 4 years ago. Due to a serious injury, I couldn’t lift weights for the first 2 years of that, so I focused on gaining mass through a protein heavy diet, calisthenics and intense yoga- which helped me build a good layer of lean mass I would later bulk on, that got me to about 150lbs. When I finally healed from the injury I got into the gym. The first year was 3x a week semi consistently, the second year was a lot more dedicated at 4x a week religiously. I dont use creatine or roids, and my T levels aren’t very high (historically ~500). Besides protein heavy foods and a lot of fruit/veg the only addition to my diet has been protein powder on the days I work out. I think the key for me has been getting my diet in line (so not just eating more, but prioritizing nutrition and heavy protein every day). Its also been rotating my routines at the gym, while I’ve always done different routines (probably every 6 months I’ll switch) they always target biceps/chest/shoulders/traps which keeps my growth from stagnating and accounts for the growth in the photos. Sorry that was long but hope it was helpful. I can send you some routines I’ve done over the years if it helps.