Since returning to the White House in 2025, U.S. President Donald Trump has put the fentanyl crisis at the center of U.S. policy toward Latin America. He imposed crushing 25 percent tariffs on Mexico and Canada for what he called their failure to stop the powerful opioid from crossing the border. He classified fentanyl as a “weapon of mass destruction,” saying that it was “flooding into our country.” The moves are part of Trump’s “all-out war” on drugs, which has included the capture of Venezuelan President Nicolás Maduro on narco-terrorism charges, and the bombing of boats believed to be carrying drugs.
Yet there are growing indications that, even before Trump took office, the United States had turned the corner on the fentanyl crisis. The data are striking. A recent study published in Science magazine noted that the annual rate of fentanyl overdose deaths had plunged by one-third between its peak in mid-2023 and the end of 2024. Seizures of the opioid had dropped 37 percent by that point, suggesting less was being smuggled over the border. The numbers have ticked down further since then.
Researchers and officials are still debating what caused such a sharp turnaround in the most lethal drug epidemic in U.S. history, one that’s caused more than 300,000 deaths. Teasing out the causes is complicated by the opacity of the criminal world. It appears, though, that the main factors may be more subtle than the drug busts or spectacular kingpin arrests that typically grab headlines.
The epidemic is still not over. Fentanyl remains the number one source of fatal U.S. overdoses, and traffickers continue to introduce deadly new synthetic drugs. But the turnaround in the fentanyl crisis offers some hope in the decades-long battle against drug trafficking and addiction.
Here are some theories on what happened.
A massive supply shock – maybe caused by China
U.S. anti-drug policy has traditionally focused heavily on reducing supply—eradicating coca and opium crops, arresting traffickers, and snagging ships and trucks transporting contraband. Many drug experts had their doubts about the long-term effectiveness of the approach. Seizing a big drug shipment “doesn’t inflict very much pain on the bad guys,” who consider it a cost of business, said Jonathan Caulkins, a veteran drug-policy researcher at Carnegie Mellon University. “They can usually just replace it.”
The illegal drug trade tends to be highly adaptable, noted Caulkins. When security forces strike at their networks, traffickers switch to new routes, identify alternative ways of making drugs or replace jailed leaders. The business is simply too lucrative to abandon. Yet, in the past year, Caulkins has been struck by what appeared to be an important disruption of supply. In the study published in Science, he and five other U.S. researchers looked not just at data on fentanyl seizures and fatalities, but what the actual users were saying. Examining the Reddit platform, the researchers found the number of posts complaining of fentanyl shortages rose in July 2023, spiked later that year and remained high in 2024, roughly tracking the drop in overdose deaths.
There were other signs of a supply shock. The DEA reported a decline in fentanyl purity throughout 2024. It appeared that fentanyl cooks in Mexico were finding it harder to get key ingredients for the opioid from China, the main producer of such precursor chemicals, the agency said. Mexican cartels are the main supplier of U.S. fentanyl. The U.S. researchers hypothesized that a Chinese government crackdown on precursors led to a huge fentanyl shortage. To test that conclusion, they examined fentanyl overdose deaths in Canada. That country’s fentanyl is largely produced not by Mexican traffickers, but by domestic criminals. Therefore, “whatever we do on the southwest border will have no effect on Canada,” said a second researcher involved in the Science paper, who spoke on the condition of anonymity. But Canada also had a notable decline in overdose deaths. What their fentanyl producers had in common with the Mexican cartels was the use of Chinese precursors.
Both the first Trump administration and the administration of former U.S. president Biden, had pressured the Beijing government to attack the illegal precursor trade, leading to a formal agreement in November 2023. Many experts initially doubted China’s ability to corral thousands of precursor producers. Now, some theorize its government may have decided that disciplining such manufacturers— a tiny part of its economy—could have outsized benefits in its relations with the United States. Still, the argument about the China connection leaves unanswered questions about precursors. “Why the heck haven’t they [traffickers] been able to figure out another source?” Caulkins said. “That’s a puzzle.”
The market for fentanyl has shrunk
If a supply shock is one reason for the easing of the crisis, a drop in demand may be another. That could explain why the street price of fentanyl in the United States hasn’t risen, despite the shortage. Some researchers say there’s probably a new equilibrium— with less of the opioid available, but less sought by buyers. There are many reasons for why the market may have contracted. Fentanyl killed off many of its customers. Meanwhile, young people in their 20s don’t appear to be taking up fentanyl the way older Americans did. They may be more aware of its dangers, highlighted in news reports and public-health campaigns.
Sometimes an enforcement action yields benefits years after it occurs. Starting in the 1990s, pharmaceutical companies introduced painkillers like OxyContin that addicted millions of Americans. When authorities tightened access to those pills a few years later, they inadvertently triggered a new round of the crisis, as desperate users turned to other opioids—first heroin, then fentanyl. But the stricter controls on prescription drugs ultimately had another effect. Many people didn’t even start using them, and so never got to fentanyl. “Fewer people have been exposed to prescription opioids in recent years, potentially curbing the development of opioid use disorder,” said a recent analysis in The Lancet Regional Health – Americas, a medical journal, by drug specialists at the U.S. Centers for Disease Control and Prevention.
Researchers point to other possible factors in declining demand. Fentanyl vendors have increasingly adulterated the opioid with less lethal substances, such as the animal tranquilizer Xylazine. That reduces overdoses but also demand: Xylazine puts users to sleep, keeping them from injecting as often. Public-health initiatives also ramped up in recent years, with the Biden administration increasing federal funding for addiction treatment by tens of billions of dollars. Federal and local governments, as well as local harm-reduction groups, have widely distributed the medication naloxone, which quickly reverses overdoses.
A host of other possibilities
Scientists and law-enforcement officials acknowledge there’s still a lot they don’t know. One senior U.S. drug enforcement official said fentanyl seizures may have fallen, in part, because the Trump administration has reassigned thousands of FBI, DEA and Homeland Security Investigations agents from narcotics work to arresting immigrants in the country illegally. “Yeah, seizures are down,” said the official, speaking on the condition of anonymity. “But we’re not looking anymore.”
Cartel conflicts in Mexico could also be contributing to the fentanyl shortfall. The U.S. government had regarded the Sinaloa cartel as the number one producer of the highly addictive opioid. For the past 19 months, though, the group has been locked in a bloody civil war, weakening its operations and at times cutting off transit routes to the U.S. border. Both Trump and Mexican President Claudia Sheinbaum have boasted of the results of their aggressive drug policies. Sheinbaum has broken with the more hands-off approach of her predecessor and mentor, Andrés Manuel López Obrador, and reported surging arrests and seizures. In his State of the Union address in January, Trump said his military campaign had “stopped record amounts of drugs coming into our country.”
Caulkins said actions by the two current U.S. and Mexico presidents didn’t cause the turnaround in the fentanyl crisis, which began before they took office. But their enforcement actions – and others in Canada – may have contributed to the supply disruption, and helped explain “why it has persisted longer than I thought it would have.” He and other experts emphasize, however, that there’s no guarantee that disruption will continue. “The incentive to restore the illicit fentanyl trade will persist as long as there is demand for the drug,” concluded the study published in Science. “It may be wise to use the current drought as an opportunity to ramp up the prevention and treatment programs that have evidence of decreasing demand.”
