San Francisco Reports First Fatal Overdose Tied to MGM-15 Opioid

San Francisco has recorded its first fatal overdose involving MGM-15, a semi-synthetic opioid derived from kratom that animal testing suggests may be 15 to 50 times more potent than morphine, city health officials said Wednesday. The death happened in late September, and the medical examiner found the drug both in the person's system and inside the packaging of a supplement the person appeared to have taken.

The product, sold under the brand Script Botanicals x Maui Labs, was marketed as "cat's claw," the common name for the plant Uncaria tomentosa. Its packaging made no mention of kratom or of 7-hydroxymitragynine, the kratom derivative that chemists modify to make compounds like MGM-15, according to the San Francisco Department of Public Health.

A supplement label that never mentioned kratom

The case is the first in the city in which a death has been formally attributed to MGM-15, also known as dihydro-7-hydroxymitragynine. The compound belongs to a family of lab-made opioids that fall outside both the licit pharmaceutical supply and the traditional illicit drug trade: they are manufactured as bulk powders, folded into capsules and gummies, and sold in convenience stores, gas stations and smoke shops as botanical supplements.

That retail channel is what makes the compounds difficult to track. California's Department of Public Health moved to ban the products late last year, but they remain widely available in smoke shops and gas stations in San Francisco and Oakland, city officials said.

The federal government has already acted on the chemical itself. The Drug Enforcement Administration placed MGM-15 and a companion compound, MGM-16, in Schedule I in late August, and a follow-up notice published Oct. 14 kept both in place while the agency reopened a separate scheduling question about 7-hydroxymitragynine, as earlier coverage of the scheduling order described. Scheduling a substance does not remove it from store shelves, and San Francisco police said this week that officers had recently executed search warrants at several smoke shops and seized hundreds of kratom and 7-OH products. The department did not say whether those seizures were connected to the fatal overdose.

What the health alert asks of clinicians

In the alert issued Wednesday, the health department asked doctors and other clinicians to routinely ask patients about over-the-counter supplement use and to counsel them about the risks, and to hand out naloxone to anyone at risk of opioid overdose. The alert was explicit about the drug's limits: naloxone may not fully restore consciousness in overdoses involving complex synthetic opioids, but it remains essential for restoring breathing.

That distinction matters for people who use drugs and for the bystanders who respond to them. Naloxone is designed to reverse opioid overdoses, and the city's advice is not to withhold it because the overdose looks unusual — but also not to assume that breathing restored means the emergency is over.

The second novel opioid death this year

It is the second time in 2026 that San Francisco has warned the public about a synthetic opioid that surfaced first in the counterfeit pill and smoke-shop trade. In April, a 16-year-old died after taking what he believed was a Xanax tablet that turned out to contain cychlorphine, an ultra-potent opioid that has since been detected in several states. That death led local health officials, Mayor Daniel Lurie and law enforcement leaders to issue a joint warning about counterfeit pills, and in September police arrested four suspects and seized more than 20,000 counterfeit pills after a months-long investigation connected to the case.

"The big concern with these products is the high potency and the problematic product labeling," Alex Krotulski, director of the Center for Forensic Science Research and Education, told the San Francisco Standard. "People have no idea if they're consuming it or how much of it they're consuming."

Krotulski said he is aware of more than two dozen deaths linked to MGM-15 nationwide, in California, Nevada, Michigan and Florida. A May report from his lab, which is federally funded, described how compounds sold under names like MGM-15 often hide synthetic additives behind vague "proprietary blend" labels — a presentation that makes them easy to market and hard for toxicology labs to detect.

Public health agencies have not approved kratom or any of its derivatives for medical use. The Food and Drug Administration warns that the plant and its concentrated extracts can cause dependence, withdrawal, seizures and overdose, and Krotulski said researchers like him are especially concerned about the newer, concentrated derivatives such as 7-OH and MGM-15.

For people who use drugs in the city, the practical guidance from clinicians is unchanged: carry naloxone, avoid using alone, and treat any product bought from a smoke shop or gas station as having unknown contents. People seeking treatment for substance use disorder can be assessed at outpatient and medication-based programs across the Bay Area.