As we have reported here, U.S. overdose deaths due to opioids, which increased steadily for 15 years to peak at 76,000 in 2022, began to decline sharply in mid-2023. The CDC showed a 24% decline in opioid overdose deaths in 2024.

Many researchers credited the decline to the widespread distribution of naloxone, a treatment that reverses an opioid overdose in its tracks. If administered in time, it is a lifesaver. However, a majority of opioid overdose deaths happen when the victim is alone and no one is there to administer naloxone.

Now, one of America’s most famous criminologists, Dr. Peter Reuter of the University of Maryland, has released a paper in the journal Science making a case that it was the Chinese government’s restrictions on precursor chemicals that resulted in a sharp decline in fentanyl supplies, leading to the decline in fentanyl-related overdoses.

Dr. Reuter authored the book, Disorganized Crime: Illegal Markets and the Mafia, in 1985, in which he proved that most criminal activity was not the result of organized crime syndicates but small, entrepreneurial, and mercurial enterprises. Dr. Reuter received the 2019 Stockholm Prize in Criminology “for his outstanding research on drug markets and public policies.”

His latest publication in Science comes as the lead author with a distinguished group of co-authors from Stanford, Carnegie Mellon, and the University of Chicago. Together, they “Synthesiz[ed] data from the US and Canadian governments and from discussions on the social media platform Reddit” to determine that there had been a major disruption in the fentanyl trade.

The full Science article is behind a paywall. A summary of the article is available from the Hong Kong-based publication, Friday Everyday. They say the researchers credit the Chinese government with cracking down on the export of precursor chemicals:

As the US problem worsened from 2020 to 2023, China eventually took further action — at no small cost to itself. It put restrictions across a much wider range of entirely legal chemicals it produced, to make it significantly harder to produce anything close to an opioid drug anywhere.

The timing suggests that this action by the Chinese government triggered a supply shock to the traffickers in the Americas by the middle of 2023. That period saw the start of a sharp drop in the number of deaths in the US and Canada.

In a news release on the University of Maryland’s School of Public Policy website, Dr. Reuter and co-author, Professor Jonathan Caulkins, lay out the “three lines of evidence” that point to a fentanyl supply disruption:

1. First, multiple indicators of fentanyl supply turned downward at the same time deaths did. Notably, the purity of fentanyl powder fell in the second half of 2023 after rising steadily for several years.

2. Consumers were getting less fentanyl — and thus running a lower risk of death — from any given purchase.

3. The amount of pure fentanyl in counterfeit pills also fell at that time, as did the number and weight of drug seizures, despite intense federal enforcement.

This last line is particularly interesting. Despite increased law enforcement, the quantity of fentanyl seizures declined. The supply was already constrained before enforcement was ramped up.

It was only last year that Dr. Reuter and his colleagues published a theoretical analysis of drug markets showing that increased overdose deaths were almost directly tied to the declining cost of opioids. The decline in cost was due to heroin being replaced by fentanyl. The cost to produce a dose of fentanyl is 2% of the cost of producing an equivalent dose of heroin, the authors state.

In the debate between whether it is a diminished supply of fentanyl or an increased supply of naloxone that is responsible for the sharp decline in overdose deaths, it should be fairly simple to determine which is more likely. If there are just as many overdoses, but fewer overdose deaths, you could make a case for the naloxone.

If there are fewer overdoses, you could make a case for fentanyl supply problems. Dr. Reuter does not appear to credit wider distribution of naloxone for contributing to lower overdose death rates. The lack of that discussion is a puzzling omission.

Written by Steve O’Keefe. First published January 20, 2026.

Sources:

“Did the illicit fentanyl trade experience a supply shock?” Science, January 8, 2026.

“What’s behind the stunning decline in American opioid deaths?” University of Maryland School of Public Policy, January 8, 2026.

“China actions likely caused steep fall in US, Canada opioid deaths: scientists,” Friday Everyday, January 10, 2026.

“Possible effects of cheap fentanyl on drug markets, use and harm: a theoretical analysis,” Global Crime, September 23, 2025.

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