Does Chewing Tobacco Increase Blood Sugar Levels?

Chewing tobacco does increase blood sugar levels. Studies consistently find that people who use smokeless tobacco products have higher fasting blood glucose, greater insulin resistance, and a meaningfully elevated risk of developing type 2 diabetes compared to non-users. The effect is driven primarily by nicotine, which interferes with the body’s ability to regulate glucose, but the story is more layered than just nicotine alone.

What the Research Shows

The connection between smokeless tobacco and blood sugar has been studied across different populations and product types, and the findings point in the same direction. A study of North Indian adult males found that tobacco chewers had significantly higher fasting blood glucose, insulin levels, and a marker of insulin resistance called HOMA-IR compared to men who did not chew tobacco.¹ These are not marginal differences; the statistical significance held across multiple metabolic markers, suggesting a broad disruption rather than a fluke in one measurement.

Looking at longer-term outcomes, pooled data from five large Swedish cohorts found that current users of snus, a form of moist oral tobacco popular in Scandinavia, had roughly a 15 percent higher risk of developing type 2 diabetes than people who never used it.² A case-control study looking at various smokeless tobacco products found that users were about 1.8 times more likely to have type 2 diabetes than non-users, even after accounting for factors like age, physical activity, body weight, and family history of diabetes.³ A comprehensive review published in 2025 concluded that smokeless tobacco use is a significant risk factor for diabetes, with the biological constituents of the products interfering directly with glucose metabolism.⁴

Why Nicotine Disrupts Blood Sugar Control

Nicotine is the primary culprit behind the blood sugar effects of chewing tobacco, and it works through several routes at once. When nicotine enters the bloodstream, it triggers the release of stress hormones like cortisol and catecholamines. These hormones signal the liver to dump more glucose into the blood, a useful response if you are running from a predator but counterproductive when it happens repeatedly throughout the day because you have a wad of tobacco in your cheek.

At the cellular level, nicotine makes muscle and fat cells less responsive to insulin, the hormone that tells cells to absorb glucose from the bloodstream. This insulin resistance means your pancreas has to produce more insulin to get the same job done. Over time, the pancreas can struggle to keep up, and blood sugar stays elevated. Research has established that this relationship is dose-dependent: the more nicotine exposure, the worse the insulin resistance.⁵

There is also a liver-specific effect. In people with type 2 diabetes, nicotine delivered through the skin via a patch reduced the liver’s ability to suppress its own glucose production in response to insulin. Cigarette smoking had an even more pronounced effect, but the nicotine alone still impaired this process compared to placebo.⁶ The takeaway: it is not just the other chemicals in tobacco causing the problem. Nicotine on its own makes the liver overproduce glucose.

Nicotine also promotes the accumulation of visceral fat, the kind stored deep around your organs. This type of fat is metabolically active and produces inflammatory substances that further worsen insulin resistance. So nicotine attacks blood sugar regulation from multiple angles simultaneously: hormonal, hepatic, and through changes in body composition.

More Tobacco, Higher Risk

One of the clearest patterns in this research is the dose-response relationship. The more smokeless tobacco you use, the more your diabetes risk climbs. The Swedish snus studies are particularly helpful here because snus comes in pre-portioned boxes, making it easier to quantify intake. People who used five to six boxes per week had about a 42 percent higher risk of type 2 diabetes than never-users. Those using seven or more boxes per week had a 68 percent higher risk. Each additional box consumed per week pushed the risk up by about 8 percent.²

This gradient matters because it suggests a genuine biological relationship rather than a statistical coincidence. If chewing tobacco and diabetes merely happened to coexist in the same populations for unrelated reasons, you would not expect the risk to scale so neatly with the amount of tobacco consumed. The fact that it does strengthens the case that the tobacco itself is contributing to the problem.

It also means that cutting back, even if you do not quit entirely, could reduce some of the metabolic harm. That is not an endorsement of “moderate” use; any use carries risks beyond blood sugar, including oral cancers. But for someone who is not ready to quit, understanding that quantity matters can be motivating.

How Chewing Tobacco Compares to Cigarettes

Many people assume that because chewing tobacco does not involve the lungs, it must be far safer than smoking across the board. For blood sugar, that assumption is wrong. A study of over 16,000 adults in the United States found that heavy moist snuff users, those going through three or more boxes per week, had roughly the same elevated risk of type 2 diabetes as people who smoked 25 or more cigarettes a day. The odds ratio for heavy snuff users was about 2.7, while for heavy smokers it was about 2.6.⁷

That equivalence surprises most people. The reason likely comes back to nicotine delivery. Chewing tobacco and moist snuff deliver nicotine through the oral mucosa, and while the absorption pattern differs from inhaled smoke, the total amount of nicotine reaching the bloodstream over a day of heavy use can be comparable. Since nicotine is the main driver of insulin resistance and glucose dysregulation, similar nicotine loads produce similar metabolic consequences, even though the routes of entry and other health risks differ substantially.

This finding does not mean smoking and chewing are equally dangerous overall. Smoking causes far more lung disease and cardiovascular damage through mechanisms unrelated to nicotine, like carbon monoxide exposure and particulate inhalation. But specifically for blood sugar control, heavy smokeless tobacco users should not assume they are in the clear.

Sweeteners Hidden in Tobacco Products

Beyond nicotine, there is another factor that rarely gets discussed: many chewing tobacco and moist snuff products contain added sweeteners. The R.J. Reynolds company began adding saccharin to chewing tobacco as far back as the 1890s, and saccharin remains the most common sweetener additive in traditional smokeless products like moist snuff today.⁸ Some products also include sugar itself, molasses, or other flavorings that contribute sweetness.

The metabolic significance of these additives is debated. Saccharin and other artificial sweeteners were long assumed to be metabolically inert because they are not digested like sugar. More recent research has raised questions about whether regular intake of artificial sweeteners can affect glucose tolerance and alter the gut microbiome in ways that influence metabolic health.⁸ Whether the amounts present in tobacco products are large enough to matter on their own, separate from nicotine’s effects, remains unclear. But if you are using chewing tobacco multiple times a day, the cumulative exposure to these additives adds up in a way that a single stick of sugar-free gum would not.

For people who are already watching their blood sugar closely, this is worth being aware of. Tobacco products are not regulated as food, so they do not carry nutrition labels. You will not find a carbohydrate count or ingredients list on a tin of snuff the way you would on a candy bar. Some of the sweetness in flavored chewing tobacco comes from actual sugars that can contribute directly to blood glucose, though the amount absorbed through the oral mucosa is likely small compared to eating sugar. The bigger metabolic concern remains nicotine.

Different Smokeless Products, Similar Risks

Smokeless tobacco is not one product. It encompasses a wide range of preparations used around the world: moist snuff and chewing tobacco in the United States, snus in Scandinavia, gutka and pan masala in South Asia, mishri powders used particularly by women in parts of India, and numerous other local variants. A study documenting usage patterns among smokeless tobacco users found that gutka was used by about 16 percent of users, gaychap by about 8 percent, and other types by 23 percent, with mishri use common among women.³

These products vary in their nicotine content, pH levels (which affects how much nicotine is absorbed), and added ingredients. Some contain lime, areca nut, or betel leaf, each of which introduces additional compounds. Despite these differences, the general pattern of increased diabetes risk holds across product types. The comprehensive review of smokeless tobacco and diabetes risk found that the association was consistent regardless of the specific product studied, though the strength of the effect varied with usage levels.⁴

This consistency across product types again points to nicotine as the central mechanism, since nicotine is the one ingredient all these products share. Some products may carry additional metabolic risks from their other ingredients, but nicotine appears to be the common thread connecting smokeless tobacco use to elevated blood sugar regardless of geography or formulation.

When You Already Have Diabetes

If you have type 2 diabetes and use chewing tobacco, the combination appears to compound the metabolic damage. A study comparing diabetic patients who chewed tobacco to healthy non-chewers found that the diabetic chewers had significantly elevated blood glucose, cholesterol, and markers of oxidative stress, while their antioxidant defenses, including vitamin C levels, were significantly depleted.⁹

Oxidative stress is a particular concern because it contributes to the complications of diabetes, including damage to blood vessels, nerves, and kidneys. Tobacco chewing appears to accelerate this oxidative damage while simultaneously depleting the body’s ability to counteract it. For someone whose diabetes is already creating a baseline of metabolic stress, adding chewing tobacco makes the body’s job harder on both sides of the equation.

There is also a practical concern around blood sugar monitoring and medication management. If nicotine is chronically increasing your insulin resistance and pushing your liver to overproduce glucose, your medication doses may need to be higher than they would otherwise be, and your blood sugar readings may be harder to predict. If your doctor does not know you use smokeless tobacco, they may attribute poorly controlled blood sugar to diet, medication non-compliance, or disease progression when the tobacco itself is a contributing factor. Being candid with your healthcare provider about smokeless tobacco use is important for accurate diabetes management.

What Happens to Blood Sugar After Quitting

You might expect that quitting tobacco would immediately improve blood sugar, and in the long run it does. But the short-term picture is more complicated than most people realize. Research on tobacco cessation, primarily studied in smokers but relevant to smokeless tobacco users because nicotine is the key driver, shows that quitting can temporarily worsen glycemic control. People who quit within the past five years had about a 54 percent higher risk of developing type 2 diabetes compared to people who never used tobacco. For those who had been abstinent five to nine years, the excess risk dropped to about 18 percent. After ten or more years, it narrowed to roughly 11 percent.¹⁰

The reason for this paradox is largely weight gain. Nicotine suppresses appetite and increases resting metabolic rate. When you stop using it, appetite increases and metabolism slows, leading many people to gain weight in the first months after quitting. That weight gain, particularly if it lands around the midsection, can temporarily increase insulin resistance and raise blood sugar. The same review identified the interplay between post-cessation weight gain, inflammatory markers, and cortisol levels as contributors to this temporary metabolic disruption.¹⁰

This temporary worsening should not be interpreted as a reason to keep using tobacco. The long-term trajectory is clear: the excess risk fades substantially over time, and the many other health benefits of quitting, including reduced cancer risk and improved cardiovascular function, far outweigh the short-term metabolic bump. But the pattern is worth knowing about, particularly for people with existing diabetes or prediabetes. If you quit smokeless tobacco and notice your blood sugar creeping up in the months afterward, the effect is likely temporary and manageable with attention to diet and physical activity. Working with a healthcare provider to anticipate and plan for this transition, including possibly adjusting medication, can smooth the process considerably.

For people considering nicotine replacement therapy as a bridge off smokeless tobacco, the situation adds another layer. Nicotine patches and gum deliver nicotine without the thousands of other chemicals in tobacco, which removes the carcinogenic and oral health risks. But since nicotine itself is a driver of insulin resistance, nicotine replacement still exerts some metabolic effect during the period it is used. That trade-off is generally considered worthwhile because the replacement therapy is temporary and far less harmful than continued tobacco use, but it is worth being aware of for anyone closely managing their blood sugar during the quitting process.

1
medRxiv. EFFECT OF TOBACCO CHEWING ON METABOLIC RISK FACTORS IN NORTH INDIAN ADULT MALES
2
PubMed. Smokeless tobacco (snus) is associated with an increased risk of type 2 diabetes: results from five pooled cohorts
3
PubMed Central. Smokeless Tobacco Use and Its Association with Type 2 Diabetes: A Case Control Study
4
Acta Diabetologica. A comprehensive review: role of smokeless tobacco consumption as a risk factor for diabetes mellitus
5
American Journal of Lifestyle Medicine. Cigarette Smoking: An Accessory to the Development of Insulin Resistance
6
PubMed. Effect of cigarette smoking and of a transdermal nicotine delivery system on glucoregulation in type 2 diabetes mellitus
7
PubMed. Cigarette smoking, oral moist snuff use and glucose intolerance
8
Nicotine & Tobacco Research. Sugars and Sweeteners in Tobacco and Nicotine Products: Food and Drug Administration’s Regulatory Implications
9
Bangladesh Journal of Medical Science. Assessment of oxidative damage and lipid profile levels in tobacco chewers with Type 2 diabetes mellitus
10
PubMed Central. The effect of tobacco cessation on weight gain, obesity and diabetes risk