Swedish Study Finds Oral Lesions in 79 Percent of Examined Nicotine Pouch Users

A Swedish clinical study found oral mucosal lesions in 79 percent of examined nicotine pouch users, adding evidence that tobacco-free pouches can cause local tissue changes where they sit against the gum.

The study reported Monday by 2Firsts does not show that 79 percent of all Swedish pouch users have lesions. The participants came from selected dental clinics with relatively high rates of daily snus use. The cross-sectional design also cannot prove that the products caused every observed change.

Most examined pouch users had lesions at the placement site

The paper was published July 1 in Oral Diseases. Researchers from Stockholm County’s Public Dental Services and Karolinska Institutet examined 272 people aged 18 to 30. The group included 126 nicotine pouch users, 63 tobacco-derived snus users, and 83 non-users.

Dentists found lesions at the usual pouch placement site in 79 percent of nicotine pouch users and 89 percent of snus users. No corresponding lesions were reported among non-users.

Oral symptoms were reported by 44 percent of nicotine pouch users and 35 percent of snus users. Burning was the most common complaint. Two pouch users had ulcers, while none were observed in the snus group.

Gingival recession appeared at the habitual placement site in 44 percent of pouch users and 52 percent of snus users. The researchers found none at corresponding sites among non-users. Receded gum tissue generally does not grow back, but this study could not determine when the recession began or what caused each case.

The researchers found no increased prevalence of caries or periodontal disease among nicotine pouch users with up to six years of use. That finding matters. Local irritation is not the same outcome as widespread tooth decay, gum disease, precancer, or cancer.

Nicotine pouches and tobacco snus produced different tissue responses

The headline number hides an important distinction. Both categories were associated with lesions, but the tissue did not always react the same way.

Hyperkeratosis—a thickening of the outer tissue layer—was more common among tobacco snus users. It appeared in 79 percent of that group and 65 percent of nicotine pouch users.

Erythema, or redness, appeared in 44 percent of pouch users and 32 percent of snus users. Oedema was found in 15 percent and 6 percent, respectively. The authors described the nicotine pouch group as showing a broader range of reactions.

Those findings fit earlier clinical observations without settling the mechanism. In 2024, Karolinska researcher Karin Garming Legert described extensive redness, sores, and blisters in some nicotine pouch users. She also stressed that researchers did not yet know how common those reactions were.

A small 2024 case series in Diagnostic Pathology examined biopsies from five long-term pouch users. All five had white lesions at the placement site. Microscopic examination found thickened tissue, swelling, and chronic inflammatory infiltration.

Five cases cannot establish prevalence. They do show that at least some visible pouch-site lesions involve measurable cellular changes rather than cosmetic whitening alone.

Flavor and pouch design remain unresolved variables

The Swedish participants reported using 40 flavor variants. The researchers saw a trend toward more severe reactions among users of five commonly reported mint products, but the association was not statistically significant. The study therefore cannot show that mint flavor caused the lesions. Nor did it find a significant relationship between lesions and declared nicotine content, moisture, wrapping material, or pouch size. Those variables were not independently controlled.

Earlier studies point in different directions, which suggests that individual formulations may produce unique outcomes. A 2022 prospective study followed 60 snus users who substituted a specific non-tobacco nicotine pouch for their usual snus. Most pre-existing snus lesions improved during the six-week study.

A separate 2025 pilot study of Stingfree Strong Blue Mint followed 23 Swedish dentists for five weeks. The pouch used an impermeable barrier on the side facing the gum. Reported lesion prevalence and severity declined, but the study was small, observational, and tested one commercial product.

Those results do not cancel the new findings. They support the new paper’s most useful implication: “nicotine pouch” is a product category, not a single standardized exposure. Product-specific testing will be needed to identify whether flavorings, pH, moisture, nicotine delivery, or pouch construction drive particular reactions.

The study does not compare nicotine pouches with smoking

The study measured oral tissue and dental findings. It did not compare nicotine pouches with cigarettes, evaluate smoking-related disease, or establish an overall risk ranking between pouch products and tobacco snus.

That boundary is essential in a tobacco harm reduction discussion. A local oral lesion can be clinically important without making a noncombustible product as dangerous as inhaling cigarette smoke. The study offers no evidence for that conclusion.

It also did not examine oral cancer or precancerous disease. Participants were young, had used pouches for no more than six years, and were examined once. Researchers could not determine whether lesions would persist, worsen, or disappear after users stopped or changed products.

The responsible reading is neither “harmless” nor “as harmful as smoking.” The study shows common local tissue changes in a selected group and identifies unanswered product-design questions. Longer prospective studies must now determine which changes are temporary, which are permanent, and which formulations are most likely to cause them.