The fentanyl on the street is starting to become weaker. Anne Milgram, who heads the Drug Enforcement Administration, announced last week that for the first time since 2021, the agency was seeing a decline in fentanyl potency, a development she attributed to the government's crackdown on Mexican cartels and international supply chains. Last year, 7 out of 10 counterfeit pills tested in DEA labs contained a life-threatening amount of fentanyl, she said, but that number has dropped to 5 out of 10.
Addiction experts say other interventions contributed to the declining fatalities, including wider distribution of overdose reversal medications such as Narcan; an uptick in some states in prescriptions for medication that suppresses opioid cravings; and campaigns warning the public about fentanyl-tainted counterfeit pills.
Harm reduction programs that offer sterile syringe exchanges and fentanyl test strips are also saving lives, experts note. Many treatment and support services that were shuttered during the coronavirus pandemic have become more accessible.
"They are all part of a health response to substance use that is bending the curve," said Dr. Brian Hurley, president of the American Society of Addiction Medicine.
But now policy and medical experts both say that shifts in the illicit drug market are a growing factor, though some of the changes also have disturbing effects.
Dr. Rahul Gupta, the director of the White House Office of National Drug Control Policy, attributed the decrease in overdose deaths in part to law enforcement efforts, including cracking down on the distribution of chemicals used to make fentanyl and other supplies that bring the drug more easily into the street supply. As a result, pure fentanyl is becoming scarcer and more expensive, he said in an interview.
Around the country, local officials and outreach workers are noticing a shift.
"We have been seeing for a while fentanyl changing: how much fentanyl is in the supply, the kinds and the form," said Traci Green, who leads a drug checking program in Massachusetts that collects samples from harm reduction groups and law enforcement agencies.
Some public health researchers theorize that the growing prevalence of other drugs, sold on their own and also mixed in with fentanyl, is altering how people use fentanyl itself.
Fentanyl is now often diluted with xylazine, an animal tranquilizer that can cause horrific skin ulcers, which have even led to limb amputations. But drug policy experts said that xylazine, in some cases, might also be having a lifesaving effect.
People addicted to fentanyl often need the drug numerous times a day. But xylazine can sedate users for hours. If someone consumes fentanyl mixed with xylazine, "you might not shoot another bag of fentanyl, because you're knocked out," said Colin Miller, a researcher at the University of North Carolina Chapel Hill, who has been interviewing drug users in Grand Rapids, Mich., and Pittsburgh about the effects of xylazine in the street supply.
Research has found that patients admitted to emergency departments for fentanyl overdoses had less severe outcomes when xylazine was also detected.
The spread of psychostimulants such as methamphetamine and cocaine may also be playing a role, medical and law enforcement experts say. But teasing apart that impact is difficult. Research suggests that stimulants are not as acutely deadly as fentanyl, though they are still dangerous. They can lead to fatal overdoses and cause chronic cardiac damage.
The ways people ingest fentanyl are also evolving, some researchers have observed, though they are not yet prepared to draw conclusions about how that is affecting fatalities.
Dr. Allison Arwady, the director of the government's National Center for Injury Prevention and Control, an arm of the Centers for Disease Control and Prevention, said fewer users were injecting fentanyl in favor of smoking or snorting it.
Policymakers and treatment experts say it's important to remember that though the improvements have been significant, drug-related deaths are still alarmingly high.
According to the latest provisional data from the CDC, overdose deaths fell to 97,000, in the 12 months that ended in June, a welcome drop below the grim 100,000 threshold that was surpassed during the pandemic but still staggering.
There were 16,000 fewer drug-related fatalities during that time period than in the period a year earlier -- a projected drop of 14.5 percent. Data suggests that in many states, nonfatal overdose rates are falling as well.
But the data also show uneven progress among racial and ethnic groups and geographic regions. Fatal overdoses among Black Americans generally increased between 2022 and 2023, while they largely decreased among white Americans, according to a recent Georgetown University analysis of state data.
Eastern and Midwestern states saw some of the sharpest fatality drops, a possible reflection of their more seasoned responses to fentanyl, which has plagued them for years.
While the overall fatality decline is welcome news, "it comes with the risk that people will say, 'We're doing OK now on drug overdoses, we're making progress,'" Arwady said.