The short version
- Different strength at the receptor. Heroin and fentanyl are full opioid agonists. Mitragynine, the leaf's main alkaloid, is a partial agonist with low intrinsic efficacy.
- A ceiling on breathing. By mouth, mitragynine's effect on breathing levels off in mice. For 7-OH by mouth the results split: its effect rose with dose in mice, and a 2026 rat study paid for by Outpost Brands found no drop in breathing. Injected into a vein, 7-OH lowers breathing like morphine. That is not how people use it. They take it by mouth.
- 7-OH is kratom too. It is in the leaf, and the body makes it from mitragynine. DEA's own notice calls it "a known metabolite of mitragynine." Concentrated products carry more of it: about 0.01 to 0.04% in leaf, 2.2 to 7.5% in the products tested.
- The fix is a label, not a ban or a cap. Tested products, the real dose on the package, 21 and up and child-resistant packs, for the leaf and every alkaloid in it.
At the receptor
Opioids work by switching on the mu-opioid receptor. A full agonist can switch it all the way on. A partial agonist can't, no matter how much you take. That difference is what separates a drug with a ceiling from one without.
- Heroin, fentanyl: full agonists
- Mitragynine: partial agonist, low intrinsic efficacy
Qualitative, not to scale. 7-OH is not on this dial. Milligram for milligram it is more potent than mitragynine, so a smaller amount does the same work.
Potency is a dosing fact. It is why the dose goes on the label, not a reason to ban it."these ligands are in fact MOR partial agonists with low intrinsic efficacy"
An older theory said kratom alkaloids were safe because they were "biased" toward one signaling pathway. Newer work doesn't back that up, so we don't use it. The case is partial agonist, low efficacy, ceiling.
Breathing
Opioid overdose kills by slowing breathing. Here is what the animal studies found, side by side. They disagree in places, and some were paid for by people with a stake. All of that is on the table.
| Study | Animal and route | Mitragynine | 7-OH | Who paid, who's involved |
|---|---|---|---|---|
| Hill et al. 2022 | Mice, by mouth | Effect on breathing leveled off above 10 mg/kg. The authors call it a built-in ceiling. | Effect rose with every dose. | Co-author Andrew Kruegel co-founded Kures and is named on mitragynine patents. |
| Labcorp study for Outpost Brands, 2026 | Male rats, one dose by mouth | Not tested. | No drop in breathing at 1, 5 or 25 mg/kg. At 5 and 25 mg/kg, breathing rate and volume went up for up to 90 minutes, then settled. | Paid for by Outpost Brands, which filed it with HHS in September 2026. A draft report, not yet peer-reviewed. |
| Henningfield et al. 2022 | Rats, by mouth | No drop in breathing up to 400 mg/kg. For comparison, one rat died at each oxycodone dose tested. | Not tested. | Funded by the American Kratom Foundation. Henningfield works for Pinney Associates, AKA's consultant. |
| Zuarth Gonzalez et al. 2025 (JPET) | Rats, injected into a vein | No drop in breathing up to 17.8 mg/kg. Breathing rate went up, and naloxone did not change that. | Lowered breathing, about 4.5 times as potent as morphine. Naloxone reversed it. | Injected into a vein, which is not how people use 7-OH. They take it by mouth. Read it with the studies by mouth, never alone. |
What we thinkBy mouth, mitragynine has a ceiling. 7-OH is more potent, and injected into a vein it acts like morphine. That is not how people use it. People take 7-OH by mouth, many of them to get away from street opioids, for severe pain that goes untreated or undertreated, and for other legitimate reasons. Even DEA's notice says many users are treating their own chronic pain.
By mouth, the animal results split, and the newest study, a draft paid for by Outpost Brands, found no drop in breathing. Route and dose matter. That is a case for a tested dose on the label, not for a ban or a cap on 7-OH.Street opioids and kratom
Different systems count deaths differently, so read these as scale, not a ranking.
- Synthetic opioids, mostly fentanyl
- 47,735 overdose deaths in 2024
- Heroin
- 2,743 overdose deaths in 2024
- Kratom involved
- about 21 a year, poison-center reports, 2015 to 2025
- Kratom, only substance reported
- about 4.5 a year, same reports
For scale on the other side, NIDA's own study listing estimates that about 10 million US adults may take kratom at least semiregularly.
What the death counts measure
"Kratom was found" and "kratom killed them" are different claims. Most of the big numbers count the first one.
- CDC poison centers, 2015 to 2025: 233 deaths where kratom was involved. 49 listed no other substance, which means none was reported, not that toxicology ruled others out. 79% involved other substances. CDC notes the data can't separate leaf from concentrated 7-OH products.
- CDC, 2016 to 2017: kratom was found in 152 of 27,338 overdose deaths. It was the only substance found in 7, and even there CDC said other substances "cannot be ruled out."
- FDPS's 5,208: cited from CDC's SUDORS system for 2020 to 2024. Its link goes to the front page of CDC's SUDORS dashboard, not to a table that shows the number. SUDORS counts drugs found or involved, not causes.
- Iowa's 45 and Arizona's 146: Iowa calls its 45 "kratom-associated." Arizona calls its 146 "kratom-related." Neither word means caused.
- North Dakota broke its number down: the governor's order cites 50 deaths, and kratom was the primary cause in 23 of them. The state's count adds 1 where it contributed.
Concentrated 7-OH
We don't dodge these numbers. The other side will put them up, so we put them up first, with what each one counts.
- How much is in it. Leaf runs about 0.01 to 0.04% 7-OH. Concentrated "extract" products tested at 22 to 75 mg per gram, 2.2 to 7.5%. Same molecule, more of it.
- How big the market got. Researchers counted 304 products with concentrated 7-OH or related compounds on sale from September 2024 to February 2025. 82.2% were 7-OH only. DEA says they sell online and in gas stations and smoke shops.
- Poison-center calls. 593 reports involving 7-OH in 2025 and 901 in the first half of 2026. Among reports with 7-OH alone, 20.5% went to the hospital. DEA's notice says poison centers only got codes for 7-OH between February and May 2025, so 2025 is not a full year of counting.
- DEA's cases. 7-OH was found in 55 fatal cases, out of 85 cases DEA selected since 2019. DEA says the samples often held other drugs too, including fentanyl, benzodiazepines and ketamine. It also says that because 7-OH is a metabolite of mitragynine, it is hard to tell leaf from a 7-OH product.
- Regular users. In NIDA's own study that tracked leaf users by phone, 66.7% met two or more use-disorder symptoms. The same study found impairment was rare, and 28% used kratom in place of opioids.
What we thinkOver a billion servings of 7-OH products have been sold. Hundreds of poison-center calls a year, against that, is a small number, and part of the climb is poison centers starting to code 7-OH in 2025. Every one of these numbers is an argument for testing, a dose on the label, an age limit and a legal store. None of them is an argument for a ban, a cap, or sending people back to fentanyl.
The article trap
DEA's 7-OH notice draws its line two ways. Leaf is covered above 0.050% 7-OH by dry weight. Processed material is covered above 0.050%, or above 1.00 mg of 7-OH "in the article." The notice never says what an article is.
Run the 1.00 mg prong on FDA's own leaf figures
- One 3 g serving at 0.04% 7-OH: 1.2 mg. Over the line.
- A 100 g bag at 0.01%: 10 mg.
- A 1 kg bag at 0.01%: 100 mg.
The prong is written for processed material, not raw leaf. Ground powder in a bag is where that gets murky. If it counts as processed and the bag counts as an article, kratom at ordinary leaf levels crosses a line the agencies say isn't aimed at leaf.
The End Gas Station Heroin Act uses a different test: under 1 mg of 7-OH per gram, and under 1 part 7-OH per 100 parts mitragynine. Two lines, two definitions, and no number either agency says is safe.
"the safety profile of these concentrated products in humans remains unknown"
DEA says no controlled trial has set a safe consumption limit. The lines get drawn anyway.
Cutting people off
Nobody has measured what happens to people after a kratom ban. There is no published outcome data yet. The closest evidence is what happened when pain patients lost their prescription opioids.
- Larochelle 2022: tapering raised the risk of overdose and suicide (RR 1.15, 95% CI 1.04 to 1.27).
- DiPrete 2022: rapid dose cuts nearly doubled overdose risk (HR 1.95, 1.31 to 2.90).
- Hopkins 2026, Australia: found lower risk after tapering (aOR 0.45). The authors tie it to Australia having no fentanyl supply. In the US, the difference is the fentanyl.
Medicine
The government is studying the leaf's main alkaloid as a medicine. NIDA, the federal drug-abuse institute, registered a Phase 1 trial of MG001, an oral mitragynine formulation. It gives single doses to 32 healthy adults who have used oral opioids in the past month, at a clinic in Overland Park, Kansas. NIDA's own listing describes mitragynine as something "some people use on their own to help manage symptoms of opioid withdrawal." The start was planned for September 2026, and as of October 2026 the listing still says not yet recruiting. It is a safety trial, not proof that mitragynine treats anything.
NIDA has already studied the people who use kratom. In 2022 its own researchers tracked 357 regular users by smartphone for 15 days. In the moment, they used it mostly for energy, getting things done and pain, and 28% used it in place of opioids. The authors found most of them used it in a way that seemed to cause no problems. The study's listing estimates that about 10 million US adults may take kratom at least semiregularly.
A third study is recruiting now at the Michael E. DeBakey VA Medical Center in Houston, led by a Baylor College of Medicine researcher. It gives 72 people with past recreational opioid use single doses of 4 to 16 grams of kratom in capsules, 30 mg of oxycodone or a placebo. Its main measure is "drug liking."
What we thinkA drug-liking test against oxycodone is how abuse potential gets measured, so watch where those results end up. Meanwhile, buprenorphine is also a partial opioid agonist, and it sits in Schedule III, regulated and prescribed. Partial agonists with a ceiling get regulated. They don't get banned.
Where the slogan came from
FDA used "gas station heroin" for tianeptine, an unapproved antidepressant sold in gas stations. Tianeptine is not kratom. Lawmakers used the phrase in press releases about tianeptine bills. It moved onto kratom through Stop Gas Station Heroin, an LLC run by the Global Kratom Coalition's executive director. The New York Times reported that Ross's allies set it up. Two kratom bills introduced in 2026 now carry it as their short title, the End Gas Station Heroin Act.
What nobody knows yet
- What 7-OH taken by mouth does to breathing in people. The animal results split, and the newest study is a draft.
- What happens to people after a kratom ban. No outcome data has been published.
- How Iowa and Arizona counted their deaths.
- When, or whether, DEA will publish a 7-OH order. It has published a notice and nothing more.
What we want
- Lab testing of every product, with results a buyer can see.
- The alkaloid dose printed on the package.
- Child-resistant packaging.
- Sales to adults 21 and up.
- No crime for simple possession.
We oppose bans and potency caps on kratom and every one of its alkaloids, 7-OH included.
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