ST. PAUL, MINN. — The Food and Drug Administration ruled in 2026 that Philip Morris International could market its Zyn nicotine pouches with claims that switching from cigarettes to Zyn reduces the risk of certain smoking-related diseases. Christy Leppanen, a former FDA toxicologist, alleged the agency authorized the product without conducting a proper assessment of the health and environmental risks posed by the pouch material, including potential microplastic exposure.

Leppanen, who joined the FDA’s Center for Tobacco Products in 2021, led a project examining the potential for microplastics exposure from tobacco products. In 2024, she was assigned to an environmental science team handling the Zyn authorization, which had been pending for four years by that time. According to Leppanen, the FDA lacked critical facts about the material composing Zyn pouches and decided not to seek additional information from Philip Morris International regarding their composition. “Fundamentally, we did not do a proper assessment,” Leppanen said.

Leppanen and several scientists stated that Zyn pouches could shed tiny particles during use that might be absorbed by users. Her concerns stemmed from both professional analysis and personal experimentation. She purchased a can of menthol-flavored Zyn at the Mall of America and conducted informal tests—placing pouches in her mouth, soaking them in saliva, heating them in a microwave, crushing them, and sucking on them. She observed that the pouches did not dissolve during these tests. This aligned with a conversation she had at a public health conference in late 2024, where an academic told her Zyn pouches do not dissolve in the mouth.

As early as April 2023, Leppanen raised concerns internally about the fate of the pouch material when tucked between a user’s gum and lip. “There’s heat, there’s enzymes … and those factors influence breakdown of these polymers into microplastics that are then consumed,” she said during a meeting, according to a recording she shared. Leppanen stated she began recording work calls after believing she faced retaliation for questioning data used in a separate cigarette authorization. She and her colleague Dilip Venugopal were tasked with updating the environmental assessment for Zyn, though Venugopal had led the initial environmental review. Recordings shared by Leppanen indicated Venugopal stated in three meetings that Zyn pouches dissolved in the mouth—a claim contradicted by her own observations.

Federal law required the FDA to issue a “finding of no significant impact” on environmental issues to authorize Zyn without further scrutiny. The agency published a document stating Leppanen had signed off on the environmental review, but later acknowledged this was a mistake. The FDA did not publicly correct the error for months. Meanwhile, the agency has not disclosed the composition of Zyn pouches: The Examination asked the FDA three times what the pouches are made of, and the agency did not respond. Philip Morris International also did not respond to requests for that information, though its website states Zyn pouches are made of cellulose, or plant fiber.

Danish researchers have concluded that nicotine pouches are made of a material similar to cigarette filters, which take years to decompose. A major United Kingdom retailer states that nicotine pouches are “not fully biodegradable.” After use, consumers discard the pouches, contributing to litter problems in some areas. Leppanen emphasized the need for clarity on the materials given emerging science on microplastics. “With the increasing body of information about microplastics exposure and how they cross into the bloodstream from the gut, we just needed to know what those materials are,” she said. Research indicates microplastics accumulate in human organs, and evidence is emerging that this accumulation could be harmful.

Two former senior FDA officials stated the review of Zyn should have addressed the pouch material, and together with another former official, they questioned whether the FDA met its legal and regulatory obligations before authorizing the product. Eric Lindblom, a former FDA policy director and lawyer, stated that federal law requires every component of a product to be evaluated. “It would be ‘careless at best and negligent at worst’ if the FDA did not scrutinize whether the pouch material itself could be harmful,” Lindblom said.

An FDA spokesperson defended the agency’s decision, stating the review “did not identify new or additional concerns about the ingredients/materials of these products specifically.” Philip Morris International praised the FDA for “its detailed scientific review.” Nonetheless, Leppanen warned of a gap between public perception and regulatory reality. “People believe the FDA is doing more than it is,” she said.

Why It Matters

New nicotine products like Zyn must be authorized by the FDA under a standard that requires them to be “appropriate for the protection of public health.” The U.S. market for nicotine pouches is projected to grow by 37% in 2026 to $6.8 billion, meaning millions of consumers could be exposed to materials that have not been fully evaluated for safety. The FDA’s 2026 marketing order allows Philip Morris International to promote Zyn as less harmful than cigarettes, a claim that carries significant public health weight if the underlying product risks—particularly from non-dissolving pouch materials—are not thoroughly understood.