First MGM-15 Death in San Francisco: the 'Cat's Claw' Supplement That Contains an Opioid

A product sold on a gas-station shelf as a botanical supplement has now been linked to a death in San Francisco. On October 21, 2026, the San Francisco Department of Public Health (SFDPH) issued a health alert to clinicians and the public after the city's Office of the Chief Medical Examiner (OCME) identified a semi-synthetic opioid called MGM-15 in an adult who died in late September.

This is the first known fatal overdose involving MGM-15 in San Francisco. The city is not describing a new street drug spreading through the illicit market — it is describing a legal-looking retail product that contained a Schedule I opioid and did not say so on the package.

Here is what the alert actually says, and what a household can do with it.

What San Francisco officials found

Three details make this alert specific.

The drug was confirmed twice. Forensic toxicology testing by the OCME detected MGM-15 in both the decedent's biological specimens and in the packaging of the product the person consumed. That is a lab-confirmed match between product and body — not an inference from symptoms.

The packaging hid what it was. The product was branded "Script Botanicals x Maui Labs," sold in packaging that makes no reference to kratom or to 7-hydroxymitragynine (7-OH) — the two names most people and most clinicians have now heard. SFDPH said this packaging is different from the MGM-15 products identified in Utah and Washington.

The product was marketed under a harmless plant name. SFDPH reports that MGM-15 has been found in items sold in smoke shops and gas stations and marketed as uncaria tomentosa — "cat's claw," a real and ordinarily benign herbal supplement sold in natural-food aisles. Utah issued a four-death warning on exactly this disguise in early October, which we covered in Utah's cat's claw alert. What is new here is the city, the fatality, and a brand that has not appeared in the earlier Utah or Washington cases.

MGM-15 — dihydro-7-hydroxymitragynine — is not a plant extract. It is a semi-synthetic kratom-derived opioid, meaning it is manufactured from a kratom alkaloid rather than simply harvested. The DEA placed it, along with MGM-16 and mitragynine pseudoindoxyl, in Schedule I by temporary order in August 2026, which makes it illegal to sell — the same federal action that set concentration thresholds for 7-OH, covered in our federal kratom-scheduling alert. Being scheduled has not removed it from shelves.

Why a "supplement" can stop someone's breathing

The clinical reason this matters is potency, and the DEA's own scheduling documents plus SFDPH's alert describe it plainly.

MGM-15 is a full agonist at the mu-opioid receptor — the same receptor that morphine, heroin and fentanyl act on. In animal models it is estimated to be 15 times stronger than morphine when injected subcutaneously and up to 50 times stronger when swallowed. Swallowing is how a tablet or capsule gets used, which puts the higher end of that range in the practical path.

That is the problem with the retail-supplement framing: a person buying a "botanical blend" has no way to calibrate a dose in the range of 50 times morphine, and the label gives no hint that calibration is needed. Opioid overdose is not a gradual experience: somnolence, pinpoint pupils (miosis), slowed or stopped breathing, and death can follow within minutes to an hour of ingesting too much.

There is one important piece of good news in the alert. MGM-15 is a mu-receptor agonist, and SFDPH says it has no reason to believe an MGM-15 overdose cannot be reversed by timely naloxone. Naloxone is not a perfect antidote to every synthetic opioid, but for this class of drug it remains the intervention that restores breathing.

Second: MGM-15 is not kratom, and kratom is not MGM-15. Plain kratom leaf carries its own dependence and liver risks, which we cover in the 7-OH dependence guide, but the acute overdose risk in these cases comes from concentrated synthetic derivatives. The label "kratom" on a package tells you almost nothing about what the tablet contains, and in San Francisco's case the package did not even say kratom.

What to do — for a person who uses, and for a family member

SFDPH asked clinicians to do four things; each translates into something a household can do.

Give naloxone for any suspected overdose, even when you are not sure what was taken. The alert's wording is direct: naloxone should be given for any suspected overdose even if there is uncertainty about which drugs were used. Naloxone may not fully restore consciousness — the person can wake up confused, agitated or in withdrawal — but its job is to restore breathing. Call 911 and stay with the person; naloxone's effect can wear off before the opioid does, so a second dose is sometimes needed while help is on the way. Our naloxone guide walks through the nasal spray steps.

Ask about supplements bought outside pharmacies. This is the half most people skip. A gas-station or smoke-shop "supplement" is not held to pharmacy standards, and the trap here is a label naming uncaria tomentosa or cat's claw. If someone in your household bought a botanical product marketed for energy, mood, pain or relaxation outside a pharmacy, the safe move is to stop using it.

Treat a mismatch as a red flag. Packaging that claims the product is legal and kratom-free while simultaneously warning that it is "for adults only" or "strongly psychoactive" is describing a controlled substance and denying it in the same breath.

Know that help does not require a diagnosis. SFDPH's fourth recommendation was to support patients in accessing substance use disorder treatment when clinically indicated, and it notes that medications for opioid use disorder are available in primary care, specialty care and by telehealth. If these products have become a daily habit, that is a clinical situation with an evidence-based treatment, not a character problem.

California's Good Samaritan law gives limited protection from certain drug-related charges to people who call 911 for a suspected overdose, which is worth knowing in the moment when fear of consequences is the thing stopping someone from calling.

Where to get naloxone and help in San Francisco

SFDPH lists free, walk-in naloxone access and treatment contacts. These are the details from the alert itself:

• Free naloxone: SFDPH Behavioral Health Services Pharmacy, 1380 Howard Street, weekdays 9 a.m.–6 p.m., walk-in, no prescription required. People who use syringe access services can also get naloxone at those sites. Naloxone is additionally stocked in most retail pharmacies.
• Naloxone for organizations and group trainings: SFDPH Naloxone Clearinghouse Project, DPH-Naloxone_Clearinghouse@sfdph.org
• Treatment linkage and addiction specialists: SFDPH, 888-246-3333
• Behavioral Health Access Center, 1380 Howard Street, (415) 503-4730
• Office-Based Buprenorphine Induction Clinic (OBIC), 1380 Howard Street, (415) 552-6242
• Methadone clinics listed by SFDPH include BAART Market, 1111 Market Street, (415) 863-3833, and BAART Turk, 433 Turk Street, (415) 928-7800

Nationally, the SAMHSA National Helpline (1-800-662-4357) is free, confidential and available 24/7 in English and Spanish, and 988 connects to the Suicide & Crisis Lifeline for anyone in distress who is not sure where else to turn.

What happens next

Enforcement is running in parallel with the health alert. On the same day, the San Francisco Police Department announced that its Narcotics Unit had served search warrants at two smoke shops: a September 10 search on the 1400 block of Haight Street, where officers seized items suspected of containing psilocybin, kratom and 7-OH packets, flavored tobacco and vapes, nitrous oxide and pipes; and an October 9 search on the 4600 block of Geary Boulevard at a shop without a tobacco license, where officers seized more than 200 flavored vapes and over 400 kratom products. SFPD said it is working with the City Attorney's Office on the investigations.

One legal detail explains why the shelves are not empty: kratom and 7-OH are not currently scheduled drugs federally, while MGM-15 is. A shop can therefore be selling kratom products that are legal under federal scheduling law and still be selling a product that contains a Schedule I opioid — which is exactly the gap the San Francisco case fell into.

The OCME continues to test for novel and emerging substances. SFDPH issued a comparable alert in April 2026 when cychlorphine, a non-fentanyl synthetic opioid, caused the overdose death of a San Francisco teenager who took it in a counterfeit pill. Both cases share a mechanism: the person did not choose an exotic synthetic opioid — they chose a product they believed was something else.

The takeaway does not depend on living in San Francisco. A package that names a harmless plant, sells for pocket money at a gas station, and contains an opioid 15 to 50 times the strength of morphine is the same risk in any state. Carry naloxone, question the label, and call 911 before you are certain.