150lb adult. Was able to put together by myself. It'll sway a bit but nothing concerning. I do want to reinforce it to wall when I'm able to. Got a mattress and topper on there, still can see railing to stop me from rolling off. Lots of space underneath. 5'6 I bumped my head a bit but can still comfortably reach everything I placed underneath. Got a dresser, desk and 50" tv under there. The ladder is cold and uncomfortable to climb, but it holds and doesn't threaten to tip the frame over. I got high ceilings and a small room so it has definitely been worth the purchase so far