How have Mexico and China changed as source countries for fentanyl and its precursors since 2018, according to U.S. agency reports?
Executive summary
U.S. agency reporting describes a clear shift since 2018: China moved from being the main direct supplier of finished fentanyl into U.S. markets to being primarily a supplier of precursor chemicals and manufacturing equipment, while Mexico evolved from a transit country into the dominant source of U.S.-bound finished fentanyl produced in clandestine cartel labs [1] [2] [3]. U.S. agencies nonetheless stress that China remains the principal upstream source of precursor chemicals and that Mexican cartels control synthesis, distribution, and the cross‑border flow into the United States [4] [5] [3].
1. China before and after scheduling: from finished fentanyl to precursors
Before the international scheduling actions of 2017–2019, U.S. reporting characterizes China as the primary direct source of finished fentanyl and analogues entering the United States, often shipped by mail or courier [6] [7]. After China and other jurisdictions moved to schedule key precursors (e.g., ANPP, NPP) in 2017–2019, U.S. law enforcement observed Chinese traffickers and chemical companies pivot toward exporting precursor chemicals and certain unscheduled inputs and equipment instead of finished fentanyl, exploiting legal export channels and online marketplaces [1] [2] [5]. Multiple U.S. agencies note that China’s tighter controls and postal monitoring reduced direct shipments of finished fentanyl, but did not stop the flow of precursors that enable production abroad [8] [1].
2. Mexico's rise: from transit zone to production heartland
Since about 2019, U.S. reports indicate Mexico has increasingly become the principal source of U.S.-bound finished fentanyl, with large clandestine laboratories in Mexico synthesizing fentanyl using precursors and equipment procured largely from China [3] [4] [9]. U.S. Customs and Border Protection and the DEA document a surge in pill and powder production in Mexico and growing seizures at the southwest border, reflecting cartel control of manufacturing and smuggling routes [9] [1]. The U.S. Treasury’s FinCEN and other U.S. analyses tie major cartels—the Sinaloa Cartel and CJNG—to managing the supply chain from PRC-sourced inputs to finished product distribution [4].
3. The enduring upstream role of Chinese chemical suppliers
Despite Mexico’s prominence in producing and trafficking finished fentanyl, multiple U.S. agency reports emphasize that Chinese companies remain the largest source of precursor chemicals and manufacturing equipment used in illicit synthesis, with PRC-based suppliers marketing precursors online and utilizing global payment channels and shipping to reach brokers and front companies [3] [4] [5]. U.S. reporting repeatedly distinguishes “source of finished fentanyl” (Mexico, post‑2019) from “source of precursors and equipment” (China), underlining that control over upstream chemical flows is central to any counternarcotics strategy [3] [5].
4. Diverging estimates, policy framing, and geopolitical incentives
Estimates of shares and flows vary across U.S. analyses and think tanks—some earlier accounts suggested direct shipments from China accounted for a very large share of U.S. fentanyl pre‑scheduling, while later work highlights the shift to Mexico-based synthesis—creating differing emphases in policy recommendations [7] [8]. Scholars warn of a “blame game” in which the U.S., China, and Mexico point fingers rather than coordinate enforcement and intelligence-sharing, an implicit political dynamic that shapes public messaging and resource allocation in U.S. agency reports [10]. U.S. domestic policy moves—public designations, aid packages, and interdiction narratives—can carry bilateral diplomatic weight and may incentivize emphasizing certain source‑country responsibilities [3] [11].
5. What U.S. agency reports do not resolve
U.S. reporting is consistent on the broad reallocation of roles—China as upstream precursor supplier and Mexico as the main source of finished fentanyl entering the United States—but does not provide a single harmonized quantification of percentages that is beyond dispute; estimates differ by year, methodology, and agency [3] [7] [12]. Where precise shares or the full mechanics of procurement networks are asserted, the underlying reports sometimes rely on law‑enforcement casework and intelligence that are partial or time‑bounded, meaning open questions remain about the evolving role of third‑party suppliers (e.g., India, intermediary brokers) and the pace at which countermeasures alter trafficking patterns [1] [2].