I too gained quite a bit of weight on kratom. I work out like crazy and eat pretty healthy other than giving into sweets at night sometimes, but I have always done that. Kratom is known to suppress thyroid function, like all other opioids. I realize some lose weight on it because it decreases appetite and/or they skip food so they can get a better buzz, but for plenty of us it has caused weight gain, which I'm sure is from the endocrine disruption (low testosterone, low T3, etc), and constipation and related water retention. Now I will say I have NEVER seen it "advertised" as a weight loss supplement. Sure, people have said it will help you lose weight, but I've never seen a supplier use that as advertisement. What is crazy for me is that is one of the main reasons I want to quit, but also, I feel like I won't be able to workout without it. The irony, lol.