January 24, 20257 min readWhats in ZYN, the FDA-Authorized Nicotine Pouch? Is It Harmful?ZYN, the popular brand of flavored nicotine pouches, recently earned FDA authorization for reducing smoking, but some questions linger. Experts explain the efficacy and potential health risks of nicotine pouchesBy Lauren J. Young edited by Dean VisserZYN smokeless nicotine pouch containers for sale at a convenience store on January 27, 2024. Bing Guan/Bloomberg via Getty ImagesNicotine pouchessmall, flavored packets placed between the gums and lipshave recently become an increasingly appealing option for people trying to avoid cigarettes and traditional smokeless oral tobacco products. Since the pouches were introduced to the U.S. market in 2014, theyve found a steady following, particularly among people between the ages of 25 and 44. This month 20 products from the popular ZYN brand became the first such pouches to be authorized by the U.S. Food and Drug Administration. While this falls short of the FDAs designation of being approved as generally safe, it allows ZYN to continue selling its three- and six-milligram nicotine pouches in 10 different flavors, including spearmint, citrus, coffee, cinnamon and menthol.The FDAs decision on ZYN, whose manufacturer, Swedish Match, had applied for authorization in 2020, was long overdue, says Jasjit Singh Ahluwalia, a physician and public health scientist at Brown University, who has studied nicotine addiction for more than 30 years. The agencys ruling drew from a study facilitated by Swedish Match that suggests the pouches got people to switch from other tobacco products such as cigaretteswhich can contain dozens of compounds linked to cancer or other diseases. Pouches such as ZYN contain substantially fewer harmful chemicals than cigarettes.The FDA apparently concluded that the public health benefits have outweighed the risks, says Mary Hrywna, an associate professor at the Rutgers School of Public Health and a founding member of the universitys Institute for Nicotine and Tobacco Studies. It doesnt mean that the products are safe.On supporting science journalismIf you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.ZYN pouches were the top-selling oral nicotine brand in the U.S. by the end of 2023; that same year Philip Morris International (PMI), the tobacco conglomerate that owns Swedish Match, reported shipping almost 385 million cans of the pouches to the U.S. More broadly, total U.S. nicotine pouch sales rose from 126 million units in the last five months of 2019 to 808 million in the first three months of 2022, according to a JAMA report. Hrywna says that the FDAs authorization of ZYN is a good first step in cracking down on bad actors.The market has exploded, and some of those manufacturers are just opportunists exploiting the lack of enforcement, Hrywna says. Now theres at least one authorized [pouch] product, and so at the very least, I would think that the FDA could now take more forcible action on products that have not submitted any type of application.Nicotine pouches rise in popularityand their potentially enticing flavors and marketinghave driven up concern about underage use. In the U.S. people must be age 21 or older to legally purchase any nicotine product, but last April the FDA issued more than 100 warning letters to brick-and-mortar and online retailers that sold ZYN to people under age 21. The 2024 National Youth Tobacco Survey found that pouch use among middle and high school students was 1.8 percent, meaning approximately 480,000 students. The FDA notes this rate among youth to be relatively lowe-cigarette use was 5.9 percent (1.63 million students) in comparisonbut groups are concerned about any level of use by kids. So-called ZYNfluencers on TikTok and other social media platforms have been criticized for promoting the pouches to young adults.In response to a request for comment, a spokesperson for PMI told Scientific American in an e-mail that U.S. affiliates are committed to responsible marketing practices focused on limiting access to adults 21 years of age and older. PMIs U.S. affiliates do not use social media influencers in the U.S. or people under the age of 35 in marketing materials. The company further stated that it uses third-party age-verification technology for marketing campaigns.Scientific American spoke further with Ahluwalia and Hrywna about how nicotine pouches work, what scientists know about their effectiveness as a tobacco alternative and what their potential health concerns are.What are nicotine pouches, and how do they work?Traditional smokeless tobacco products, often called snuff, dip or snus, consist of ground tobacco leaves sealed in tiny permeable bags or placed directly into the cheek. ZYN and other pouches instead contain a manufactured powder of nicotine salts (derived from natural tobacco or made synthetically), flavorings and fillers.Most users spit out a nicotine pouch after 15 minutes to an hour. While its tucked between the gum and lip, the nicotine salts dissolve and diffuse through the porous, tea-bag-like pouch, absorbing into the mouths mucosal lining. When it does that, it enters the blood system, Ahluwalia says. Nicotine molecules bind to the bodys nicotinic acetylcholine receptors, which are involved in regulating the dopamine reward system, and the resulting feel-good sensation is what makes nicotine addictive.Individual nicotine pouches.Andrii Atanov/Getty ImagesHow effective are nicotine pouches at curbing cigarette use compared with other alternatives?Various nicotine products such as gum, patches, lozenges and pouches can be used as an alternative to cigarettes and other tobacco products, presumably reducing some health riskssuch as those associated with the combustion of smokingor making it easier to quit entirely by tapering off nicotine in a measured way.An effective nicotine addiction treatment typically involves mimicking the peaks and troughs of the smoking experience, Ahluwalia says. After a puff on a cigarette, in five minutes, you have peak levels of nicotine, and then it goes down after about 30 minutes. So its a perfectly addictive drug, he explains. Your nicotine receptors are naked and hungry for more, so you take another cigarette, and its just a beautiful vicious cycle.One cigarette can contain 10 to 15 mg of nicotine. A piece of nicotine gum often has much lessbetween 2 and 4 mg. Pouches, especially if a higher dose like six milligrams and eight milligrams, can emulate a cigarette more in getting higher levels of nicotine, Ahluwalia says. It wont give you that same peak, but it can get to some good levels that are respectable enough to sort of saturate the nicotinic receptors in your brain. (Ahluwalia is currently developing a prescription pharmaceutical product that delivers nicotine in the lungs, and he has served on scientific advisory boards of various manufacturers of nicotine products.)One of the company-led assessments submitted to the FDA found that 24 percent of people who had used cigarettes, traditional smokeless tobacco products or both in addition to ZYN switched completely to the new pouch products after 10 weeks. Another assessment found that in a separate survey group, the proportion of people who used cigarettes in addition to ZYN decreased from 42 percent to 15 percent over a median time of five to six months.There is evidence that the [pouch] products deliver substantial levels of nicotine that are able to curb tobacco-related withdrawal symptoms, Hrywna says, but she adds that additional independent studies in humans are needed. I think we need more evidence on whether nicotine pouches promote long-term, sustained product switching and that they actually reduce the harm from tobacco, she says.What do we know about nicotine pouches health risks?In a review of nicotine pouch studies, human trialsall funded by pouch manufacturersshowed minimal damage to tooth enamel and reductions in preexisting oral lesions from other tobacco products. Urine and blood samples from people using the VELO brand nicotine pouch contained lower levels of several harmful biomarkers compared with samples from cigarette smokers. But a biomarker of oxidative cell damage, along with two biomarkers related to cardiovascular disease risk, were not significantly different from those found in smokers.Like any nicotine product, the pouches can have short-term side effects such as elevated heart rate, irritation and nausea. The small packets shouldnt be chewed or swallowed. Some nicotine from pouches will inevitably be ingested into the stomach when people swallow their saliva. The liver will eventually metabolize it, but Ahluwalia says this can cause side effects such as hiccups and bloating.We know that nicotine pouches do contain far, far fewer harmful constituents compared to traditional tobacco products, Hrywna says. A 2023 toxicological screening of 48 nicotine pouches from 22 brands identified 186 chemical components in addition to nicotine; eight of these are considered hazardous by the European Classification, Labeling and Packaging Regulation, and three are classified as possibly carcinogenic to humans by the International Agency for Research on Cancer. But the overall number of chemicals is still much lower than that of those typically found in cigarette smokewhich can contain more than 7,000 chemicals.Assessing the relative harms and risks of nicotine is nuanced, Ahluwalia says. Considerable research has found links between nicotine and cardiovascular disease, cancer and cognitive development in growing brains, but findings in humans are not completely conclusive. Research does show that nicotine causes clear health risks during pregnancy; it can cross the placental barrier and affect the fetus, Ahluwalia notes. Addiction is also a major concern with any product containing nicotineand these pouches do have a very high potential for nicotine dependence, Hrywna says.Because nicotine pouches are so new, the amount of safety and efficacy evidence is still relatively small, Hrywna says. In the FDAs authorization announcement, the agency said it will closely monitor the marketing and use of these products. We dont want to see young people taking up nicotine in any form, Hrywna says. If youth use becomes problematic, I think the FDA now has a stronger legal basis to take action on marketing of authorized products and removing unauthorized products in the market.