Sen. Chuck Schumer called last week for a crackdown on ZYN, a nicotine pouch that has become increasingly popular in the United States, alongside the rise of so-called Zynfluencers who tout the product online.

Nationwide sales of nicotine pouches, which users tuck into their upper lips, rose dramatically, with 808 million pouches sold in the first three months of 2022 alone, according to an analysis of four major brands. ZYN, which has quickly established a large footprint in the United States, accounted for the majority of sales in the analysis.

“These nicotine pouches seem to lock their sights on young kids,” Schumer said, warning that products like ZYN could hook a new generation on nicotine. A 2023 study from the Centers for Disease Control and Prevention found that around 1.5 percent of middle and high school students reported using nicotine pouches in the last 30 days.

ZYN says its product is only for consumers 21 and older who already use nicotine. “Our marketing practices — which prohibit the use of social media influencers — are focused on preventing underage access and set the benchmark for the industry,” a representative for Phillip Morris International, the parent of the company that manufactures ZYN, wrote in a statement.

Because ZYN and similar pouches are relatively new, their long-term health effects aren’t clear, said Minal Patel, a senior principal scientist at the American Cancer Society. The risks will largely depend on who’s using them and how often. Nicotine pouches are much less harmful than cigarettes, said Jonathan Foulds, a professor of public health sciences and psychiatry at the Penn State University College of Medicine, and so for someone who currently smokes, switching to a pouch might lower health risks.

But for people who have never used tobacco — especially teens and young adults — experts urge caution.

Newer products like ZYN could “really drive nicotine addiction and nicotine enjoyment,” said Dr. Panagis Galiatsatos, a pulmonary and critical care medicine physician at Johns Hopkins Medicine. “It’s the same problem we face with electronic cigarettes.”

What are nicotine pouches?

Nicotine pouches are small, pillowlike containers of nicotine salt, which absorbs through tissues in the mouth. They often contain flavors and sweeteners and look similar to snus, a type of tobacco pouch popular in Scandinavia. The nicotine in ZYN is derived from tobacco leaf. But unlike other nicotine-containing products, such as snus, chewing tobacco and dip, ZYN and similar pouches don’t contain tobacco leaf itself.

What’s known about nicotine and cancer risk

Nicotine is not considered a carcinogen. While smoking cigarettes can cause lung and other cancers, and snus has been linked to increased risk of gastrointestinal cancers, the cancer risks of tobacco-free nicotine pouches aren’t yet clear. The pouches may contain other carcinogens, Patel said.

“Most of what we know comes from the nicotine pouch industry,” said Brittney Keller-Hamilton, an assistant professor at The Ohio State University College of Medicine who has studied nicotine pouches. A rare independent study looked at 46 pouch products in Germany and found that 26 contained compounds known as tobacco-specific nitrosamines, which can cause cancer. ZYN nicotine pouches do not contain “any quantifiable levels” of these compounds, a representative said in an email.

Other potential health harms

The nicotine in these pouches can be addictive. They are typically sold in the U.S. in around 3 or 6 milligram strengths; smokers absorb around a little more than 1 milligram of nicotine from a cigarette, by comparison.

Teens are particularly vulnerable to addiction, because their brains aren’t fully developed, said Dr. Keller-Hamilton. “We don’t know what the end result of what a young person using nicotine pouches is — we don’t know if they would just stay using nicotine pouches until they quit, or if they start seeking other forms of nicotine that might have faster nicotine delivery, like a cigarette,” she said.

Brian King, director of the Food and Drug Administration’s Center for Tobacco Products, said in a statement that the agency “remains concerned about any tobacco product that may appeal to youth.” (The FDA classifies nicotine pouches as tobacco products.)

Some experts think nicotine deteriorates gum tissue, which could lead to periodontal disease, said Irfan Rahman, a researcher at the University of Rochester Medicine who has studied nicotine pouches.

Nicotine can also increase blood sugar and raise your heart rate and blood pressure. “It probably has a small, but real effect on your cardiovascular risk,” Foulds said. Nicotine may also harden the walls of arteries in the heart, contributing to heart disease and attacks.

Experts are also concerned about the risks nicotine pouches pose to pregnant women and their fetuses. Dr. Bendik Brinchmann, a physician and researcher at the National Institute of Public Health and the National Institute of Occupational Health in Norway, said that several studies show women who use snus during pregnancy may face a higher risk of preterm birth and stillbirth, which he suspects are related to nicotine exposure. Those risks may carry over to tobacco-free nicotine pouches, he said. “My major concern is towards the young women that really can get addicted to this,” he said.

“If you start, it’s much harder to quit.”

Blum writes for The New York Times.