MSten has never been a bulking agent. At best a good strength and recomp and you need to run it 20mg and up to get really good results. You are not going to be seeing massive gains from this. YOu want more gains find a solid DMZ and run it at a higher dose. I guess out of things legal now MSten might be considered a bulker but when other stuff was around that actually put real size on it was at best a very good recomp and strength agent.
13 lbs from glycogen? I could see that possibility if you were on a very carb restrictive diet like keto or something before then I see why you think a good amount of that could be glycogen. Otherwise, I would say 13 lbs is pretty damn good for 4 weeks of msten. Sounds like you might have gained a solid 7-8 lb or so of lean mass. That is impressive in 4 weeks with msten. An 8lb gain of lbm will completely change the way your physique looks when you lean back out and can maintain it.
Stronger binding to the AR especially in fat cells. Makes cutting and strength gains much better.
SOunds about par for the course with this product. I think quite often they pick people who are cutting, recomping or coming off of a cut and going straight into a bulking cycle.
Juicedeez utz - I just saw your post saying you had gotten sick prior to the cycle. I often recommend people who are starting a cycle after a cut, or in your case an illness to start increasing carbs and food intake first before starting the cycle. That way no glycogen gains will be counted as actual gains from the cycle confusing the issue. That or at the end of the cycle I will have them deplete themselves and weigh themselves again to see how much they really gained. If you want to know how much you really gained go keto for 3-7 days, replacing all your calories with a little extra protein and a lot of healthy fats. Weigh yourself at the end of the week and you can see what the non glycogen based gains were since you will be depleted like the beginning of the cycle.