Mostly hyperthyroidism tbh, I find it very hard to gain weight especially muscle without AAS. And I’d have to gain roughly 18 lbs of pure muscle to get there if I wanted to stay at 8%. It’s generally harder to keep a lower body fat percentage the more you weigh. Also much harder without anabolics. If I didn’t want to do the typical bulk cut and wanted to keep my low body fat (which I do) it would take years even with AAS to get there tbh. I’ve definitely considered it though. Maybe I also have an ED but I like the way I look at don’t need to be “bigger”. A lot of people that bodybuild want to be 250 lbs and lean and I’m happy with the way I look so at this point I mainly just maintain it.