A peer-reviewed study published July 1, 2026 in the journal Oral Diseases, conducted by Karolinska Institutet's Department of Dental Medicine in collaboration with Public Dental Services, Stockholm County, examined 272 people aged 18 to 30 across nine dental clinics. The study compared 126 nicotine pouch users, 63 users of traditional tobacco-derived snus, and 83 non-users. It is described as the first clinical comparative study of its kind directly comparing tobacco-free nicotine pouches against traditional tobacco-based snus for oral tissue effects. The headline finding is not that one product is safer than the other. It is that they produce genuinely different reaction patterns in the oral mucosa, and the differences are more specific and more interesting than a simple "milder vs. worse" comparison.
What the Study Actually Found
The researchers looked at three specific types of oral reactions at the placement site, commonly known as a snus lesion: hyperkeratosis, which is a thickening of the oral tissue; erythema, which is redness; and oedema, which is swelling.
The results showed clear differences between the two user groups:
- Hyperkeratosis was more common among traditional snus users at 79 percent, compared to 65 percent among nicotine pouch users
- Erythema was more common among nicotine pouch users at 44 percent, compared to 32 percent among traditional snus users
- Oedema was found in 15 percent of nicotine pouch users and 6 percent of traditional snus users
Both nicotine pouch users and traditional snus users showed reactions in the oral mucosa at the placement site. The reaction patterns differed between the two groups, but neither group was reaction-free.
Why the Reaction Patterns Matter More Than a Simple Ranking
The common assumption in discussions about nicotine pouches is that removing tobacco automatically means gentler effects on oral tissue. This study complicates that narrative. Traditional snus caused more thickening of the tissue, which might sound worse at first glance. But nicotine pouches caused more redness and more swelling, which are signs of inflammation. These are different biological responses, not simply scaled versions of the same problem.
Hyperkeratosis is the body's way of protecting tissue against chronic irritation. It is a structural adaptation. Erythema and oedema, by contrast, are acute inflammatory responses. One pattern suggests long-term adaptive thickening. The other suggests ongoing inflammatory irritation. Which is more concerning depends on the clinical context, and the study does not resolve that question. What it does establish is that the two products do not produce the same oral environment.
What Karin Garming Legert Said About Unpredictability
Karin Garming Legert, Associate Professor and senior consultant at Karolinska Institutet's Department of Dental Medicine, said in the university's own published statement that nicotine pouches cause reactions in the oral mucosa that are harder to predict than traditional snus, and that severity varies more from person to person.
This is arguably the more important finding than any single percentage. Traditional snus reactions followed a clearer pattern: higher consumption correlated with more noticeable reactions. With nicotine pouches, no clear correlation of this kind was observed. This means that a light user of nicotine pouches might experience more oral irritation than a heavy user, or vice versa, and the study's data does not provide a reliable way to predict who will be affected more severely.
For individual users, this unpredictability has practical implications. You cannot assume that using fewer pouches will automatically reduce your oral reaction risk. You need to pay attention to your own mouth, look for redness or swelling at the placement site, and not rely on general population averages to predict your individual response.
The Important Limitations
The study has several limitations that are worth understanding before drawing conclusions.
First, the design is cross-sectional. This means it captures a snapshot in time rather than following participants over months or years. It can show associations between product use and oral reactions, but it cannot establish that either product caused the observed changes. The reactions might be influenced by other factors that the study did not measure.
Second, the study found no higher prevalence of cavities or gum disease specifically among either user group compared to non-users. The observed differences were limited to reactions at the placement site in the oral mucosa.
Third, the study did not compare either product category to cigarette smoking. Any inference about how nicotine pouches or snus compare to cigarettes would require a different study design.
These limitations do not invalidate the findings. They simply define what the study can and cannot tell us. It tells us that nicotine pouches and snus produce different oral tissue reactions. It does not tell us which is safer overall, which causes long-term harm, or how either compares to smoking.
What This Means Practically
This is not a reason to panic. It is a reason to pay attention to your own individual reaction rather than assume pouches are automatically the safer choice for oral tissue specifically.
If you use nicotine pouches, check the area where you place them. Look for redness, swelling, or any change in tissue texture. Rotate placement sites if possible. If you notice persistent irritation, that is a signal worth acting on, regardless of what population averages say.
For anyone considering switching from snus to nicotine pouches specifically to reduce oral irritation, this study suggests the trade-off is more complex than commonly assumed. You might reduce hyperkeratosis but increase erythema or oedema. Whether that is an improvement depends on your individual response and your priorities.
The broader context of oral health from nicotine pouch use is covered in our guide to the ZYN oral microbiome and bacteria, which examines how pouch use affects the bacterial environment in the mouth. For concerns about gum recession specifically, our article on ZYN gum recession and dental health covers what is known and what remains uncertain.
Frequently Asked Questions
What is hyperkeratosis in the context of nicotine pouch use?
Hyperkeratosis is a thickening of the oral tissue at the placement site. It is the body's protective response to chronic irritation. The Karolinska study found it was more common among traditional snus users at 79 percent compared to 65 percent among nicotine pouch users.
What is erythema and why was it more common in nicotine pouch users?
Erythema means redness of the tissue, indicating inflammation. The study found it in 44 percent of nicotine pouch users compared to 32 percent of traditional snus users. This suggests nicotine pouches may produce more inflammatory irritation at the placement site than snus, even though they are tobacco-free.
What is oedema and how common was it?
Oedema means swelling caused by fluid accumulation. It was found in 15 percent of nicotine pouch users and 6 percent of traditional snus users, making it the least common reaction but still notably more prevalent among pouch users.
Does this study prove nicotine pouches are worse for your mouth than snus?
No. The study found different reaction patterns, not a simple ranking of worse vs. better. It also cannot establish causation due to its cross-sectional design. The reactions might be influenced by factors the study did not measure.
Did the study find more cavities or gum disease in nicotine pouch users?
No. The study specifically found no higher prevalence of cavities or gum disease among either nicotine pouch users or snus users compared to non-users. The observed differences were limited to reactions at the placement site in the oral mucosa.
How does this compare to cigarette smoking?
The study did not compare either product to cigarette smoking. Any comparison to cigarettes would require a separate study.
What should I do if I notice redness or swelling where I place nicotine pouches?
Pay attention to persistent irritation. Rotate placement sites if possible. If redness or swelling persists, consider it a signal to evaluate your use. Individual reactions vary, and the study found that pouch-related reactions are harder to predict than snus-related ones.
What does it mean that severity varies more from person to person with nicotine pouches?
It means that consumption level is not a reliable predictor of oral reaction severity for nicotine pouches, unlike traditional snus where higher use correlated with more noticeable reactions. Light users might experience more irritation than heavy users, so individual monitoring matters more than relying on general averages.
This article is based on a peer-reviewed study published July 1, 2026 in the journal Oral Diseases, conducted by Karolinska Institutet's Department of Dental Medicine in collaboration with Public Dental Services, Stockholm County.
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