Doctors at Rush University Medical Center say they're seeing more patients seeking treatment for addiction to 7-OH, an unregulated, highly concentrated synthetic derivative of kratom that's sold in colorful packaging at convenience stores, gas stations, smoke shops and vape shops across the Chicago area. While Rush has treated relatively few overdose cases tied to the substance, physicians say the pattern they're watching unfold looks a lot like opioid dependence.
An Opioid-Like Grip Forms Fast
Also known as 7-hydroxymitragynine, 7-OH has effects similar to an opioid, according to FOX 32 Chicago. Some people use it for pain relief, while others buy it purely for its intoxicating effects. Dr. Antonia Nemanich, an assistant professor of emergency medicine, medical toxicology and addiction medicine at Rush University Medical Center, said 7-OH is highly concentrated and acts similarly to an opioid, and that dependent users buy more of it to maintain the same effect or avoid withdrawal.
Some kratom users escalate from one product a day to as many as ten within a relatively short period, the station's report notes. Products vary widely in how much 7-OH they actually contain, which makes dosing unpredictable even for people trying to manage their own use. Nemanich said the resulting dependence is not cheap, since users need increasing amounts just to feel normal.
Withdrawal Symptoms Mirror Opioid Detox
Withdrawal from 7-OH can bring on severe muscle cramps, vomiting, nausea, diarrhea, sweating and severe malaise, per the same account. Rush physicians say they've seen a real increase in patients seeking treatment for 7-OH addiction, even as poison control centers report a parallel jump in calls tied to the substance. That surge shows up in state-level data too: the CBS News Chicago found Illinois poison control reports involving kratom reached 145 in 2025, more than double the 2024 total, while national poison control centers began tracking 7-OH in 2024.
The pharmacology helps explain why. Natural kratom leaves contain less than 2% 7-hydroxymitragynine relative to total alkaloid content, but preclinical research cited by the U.S. Food and Drug Administration indicates that isolated or semi-synthetic 7-OH can be up to 13 times more potent than morphine at mu-opioid receptors. That's the gap between the plant and the concentrated 7-OH products now on Chicago-area shelves. In July 2025, the FDA issued a formal scientific assessment recommending that concentrated 7-OH products be placed in Schedule I of the Controlled Substances Act, citing risks of respiratory depression, physical dependence and addiction.
Local Police and Village Boards Move Ahead of Springfield
The Posen Police Department recently warned residents in south Cook County about the potential dangers of 7-OH. In a public safety advisory issued this month, the department cautioned that the products are sold at local gas stations and smoke shops. The FDA advises consumers to avoid 7-OH products altogether, noting they are not approved for safe or effective medical use.
Some municipalities are already considering outright bans, and several have gone further. Because Illinois's statewide law imposes no testing requirements or concentration limits on 7-OH, cities including Bloomington, East Peoria, Morton and Pekin have passed local ordinances banning retail sale or possession of kratom and 7-OH products, according to WGLT. Oak Park took a narrower approach in July, updating its ordinances to require a $300 licensing fee and a $1.31 per-unit tax on kratom retailers while board members discussed a possible full ban on concentrated 7-OH extracts, per the Wednesday Journal of Oak Park and River Forest.
Illinois Law Still Sets No Statewide Potency Limit
Illinois bans kratom sales to people under 18, but the law sets no testing requirements or concentration caps on 7-OH statewide, per the Illinois General Assembly. That gap is now the subject of proposed legislation in Springfield aimed at cracking down on 7-OH, alongside proposals to regulate it.
The federal picture has moved in parallel. In June 2025, the FDA sent a warning letter to distributor 7Tabz Retail, LLC, classifying its concentrated 7-OH products as illegal unapproved new drugs and citing adverse event reports that included liver toxicity, seizures, respiratory depression and deaths, according to ISSUP. Massachusetts issued a statewide emergency order in August placing all kratom and synthetic derivatives into Schedule I, a move Hoodline covered in its report on Norwood's local kratom ban, while California health regulators had seized more than $5 million in unapproved 7-OH and kratom goods by early 2026.
For now, Rush's warning centers on what its own emergency room and addiction medicine staff are seeing walk through the door: patients whose use escalated quickly, whose withdrawal symptoms resemble opioid detox, and whose dependence keeps getting more expensive. As Nemanich and her colleagues watch that pattern grow, the question of whether Springfield settles on a ban or a regulatory framework — and what further federal action may follow the FDA's warning letters and scheduling recommendation — remains open.
