My brother started on the occasional uei mixes (roughly 20% uei), for a few months, then went to straight uei. He got to the point to where he felt like shit after about 8 hours of his last dose, so he did the sensible thing, dose again of course. Well, his tolerance sky rocketed like expected by us both, but he had the money and loved the way it made him feel, more so in the beginning at least. When he managed to moderate his use, and withdraw for a little while, the first doses really made him feel like everything was right (euphoria). It gave his tons of motivation to get things done and made him score high on his college exams, which were tough. It improved his normally bland personality 10 fold and made his a very charming guy. No one ever suspected a thing but it ended up costing him over $40-50 per day towards the end, using it almost daily for nearly a year. Of course it didn't cost that much in the beginning or middle but still a ton of money blew on this shit.
A few times he did quit C/T after heavy use and quickly of course could not stand the w/d and caved. He'd proceed to order an overnight fedex package containing his needed fix. He claims the withdrawals were absolutely unbearable, worst being restless legs, endless insomnia, cold but very sweaty, time passing ridiculously slow, anxiety, depression, some vomiting, can't hold down food, etc, etc. So after talking about it and with our research, he finally got some sense and tapered to just enhanced bali and then just powdered leaf, all steps taking less than a week, then jumped but had an arsenal of clonidine, valium, immodium, hot baths, l-tyrosine, vitamins, etc, etc. Looking back, he says he feels like a lil bitch since withdrawal was fairly easy and short term, like 3 days after jumping and he was back to baseline. He says he has CT off of short-term binges of hydros and oxys with no taper, and just "felt like shit" for a couple days. But the kratom w/d caught him off guard initially, but in the end he concludes that it isn't so awful if you taper just a lil bit.
Healthwise, kratom (powered leaf at least) has provided mass fiber and that is clear from hearing how regular he says he was at least. He also noticed that several warts on his fingers and toes which were growing to the point of him hiding them with band-aids. The ones on his toes made it painful to walk. He says that about 1 month after starting kratom, they almost fully cured, or went dormant or w/e, being viral, but are completely gone visually. This could just be a coincidence in my opinion, but he claims that there might be some kind of immune system boost or something provided by kratom since he changed nothing else at the time.
To this day, he has been off kratom for about 6 months. He doesn't consider using it again because he pretty much avoids costly habits since he thinks they aren't worth it. At least the uei and maybe tincture mixed with uei he liked a lot, but it still cost too much. He even said he thinks opiates would be a better option if he had to choose since it takes less to get high and they typically last longer. But he claims to have tried everything except dilaudid and fentanyl and kratom at the right dose and extract made him feel better than anything else he's tried, opioid wise.