How much illegal fentanyl in the US originates from China versus Mexico?
Executive summary
Law enforcement and analysts say the U.S. illicit-fentanyl supply chain is a two-country system: Chinese chemical manufacturers and brokers supply most precursor chemicals, while Mexican cartels have become the principal producers, traffickers and distributors into the U.S. (reports: China as main source of precursors; Mexico as main production/trafficking base) [1] [2] [3]. Estimates of exact percentages vary by period and method; prior to 2020 much finished fentanyl reportedly arrived directly from China, but since China moved to class‑wide controls in 2019 the flow shifted toward China→Mexico precursor shipments and Mexico→U.S. finished‑product trafficking [2] [4].
1. China supplies the chemicals; Mexico supplies the labs and routes
Multiple U.S. government and policy analyses describe a clear division of labor: industrial chemical manufacturers and brokers in China produce and export precursor chemicals and certain finished substances, while Mexican transnational criminal organizations (TCOs) operate clandestine labs, press counterfeit pills, and move finished fentanyl across the southwest border [5] [4] [2]. The DEA and other agencies say “most” precursor chemicals flow from industrial suppliers in China to Mexican cartels, which then synthesize fentanyl for U.S. distribution [1] [4].
2. The quantitative picture changed after China’s 2019 controls
Before China imposed class‑wide controls on fentanyl‑related substances (around 2019), analysts say a very large share of finished fentanyl consumed in the U.S. was shipped directly from China—Brookings cites a figure that “prior to the scheduling, prior to 2020, we had 90% of fentanyl consumed in the U.S. being shipped directly from China” [2]. After those controls, trafficking patterns shifted: direct China→U.S. shipments fell and China→Mexico precursor flows rose, with production in Mexico increasing [2] [4].
3. Government sources avoid single‑number breakdowns; reporting gives process more than a fixed percentage
Recent official and investigative sources emphasize process and dominant roles rather than a single, definitive split of tons or doses by origin. The DEA, DOJ and congressional reports repeatedly identify China and Mexico as the primary sources without producing a stable percentage breakdown that survives changing enforcement and market adaptation [4] [5] [1]. Available sources do not provide a current, universally agreed percentage split of illegal fentanyl by weight or dose originating in China versus Mexico.
4. Indicators used by analysts differ and drive divergent impressions
Studies and reporting rely on different indicators—seizure origin, chemical forensic tracing, indictment targets, ports of entry, or production location. For example, seizures of finished fentanyl sourced to China tended to be small but high‑purity shipments, while larger bulk seizures and the majority of border interdictions are linked to Mexico [6] [7]. Brookings and other policy pieces stress the change from finished‑product exports from China to precursor exports from China used in Mexican production [2] [8].
5. Enforcement and indictments show active China→Mexico links
U.S. prosecutions and public‑facing DOJ press releases in 2025 charged China‑based chemical firms for exporting precursor chemicals and additives to purchasers in Mexico and the United States, illustrating the supply‑chain role of Chinese firms and the operational role of Mexican cartels in manufacturing and distribution [5] [9]. U.S. agencies and independent analysts therefore treat China’s role as primarily upstream (inputs) and Mexico’s role as downstream (production and trafficking) [4] [1].
6. Politics, tariffs and rhetoric complicate the debate
Political actors have used the supply‑chain facts to support tariffs or diplomatic pressure. Reporting notes the Trump administration’s tariffs and public claims, while outlets such as NPR and Brookings caution that some political statements overstated or simplified the picture—particularly about direct‑origin shares and Canada’s role—underscoring that policy responses can be motivated by geopolitics as much as forensic evidence [3] [1] [10].
7. Bottom line for readers
If your question asks “how much originates in China versus Mexico,” the best answer in current reporting is: China is the principal source of precursor chemicals and—before 2019—of much finished fentanyl shipped directly to the U.S.; since China’s scheduling the dominant practical pathway has become China→Mexico (chemicals) and Mexico→U.S. (finished fentanyl and trafficking). Sources document the roles clearly but do not converge on a single, up‑to‑date percentage split by weight or doses that holds across years and enforcement changes [2] [4] [1]. Available sources do not provide a definitive numeric share that answers “X% from China, Y% from Mexico” for the present moment.