Can you smoke with type 2 diabetes? Whilst it is physically possible to smoke with type 2 diabetes, doing so substantially worsens blood sugar control and dramatically increases the risk of serious complications. Smoking interferes with insulin action, making glucose levels harder to manage, and accelerates damage to blood vessels throughout the body. For people living with diabetes, smoking significantly raises the risk of heart attack, stroke, kidney disease, vision loss, and lower limb amputation. Quitting smoking is one of the most important steps you can take to improve your health and diabetes outcomes, alongside medication and lifestyle measures.
Summary: You can physically smoke with type 2 diabetes, but doing so significantly worsens blood sugar control and greatly increases the risk of heart disease, stroke, kidney damage, vision loss, and amputation.
- Smoking increases insulin resistance, making blood glucose levels harder to control with medication or lifestyle changes alone.
- People with diabetes who smoke face markedly higher risks of cardiovascular disease, diabetic retinopathy, nephropathy, neuropathy, and foot complications including amputation.
- Quitting smoking improves circulation within weeks, may enhance glycaemic control over time, and substantially reduces long-term complication risks.
- NHS stop smoking services offer free, evidence-based support including nicotine replacement therapy, prescription medications, and specialist advice tailored to diabetes management.
- Blood glucose monitoring should be intensified after quitting, as improved insulin sensitivity may require medication dose adjustments to prevent hypoglycaemia.
- Smoking cessation is identified by NICE and NHS guidance as a critical intervention for improving outcomes in type 2 diabetes, alongside glucose, blood pressure, and lipid control.
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How Smoking Affects Type 2 Diabetes
Smoking has a profound and detrimental impact on type 2 diabetes, primarily through its effects on insulin resistance and glucose metabolism. Nicotine and other toxic compounds in cigarette smoke trigger the release of stress hormones such as cortisol and adrenaline, which interfere with insulin action. This makes it significantly harder for cells to absorb glucose from the bloodstream, leading to persistently elevated blood sugar levels that are more difficult to control with medication or lifestyle measures alone.
The interaction between smoking and diabetes extends beyond immediate glucose dysregulation. Chronic smoking induces a state of systemic inflammation and oxidative stress, damaging the delicate endothelial lining of blood vessels throughout the body. For individuals with type 2 diabetes, who already face increased cardiovascular risk, this additional vascular injury accelerates the progression of microvascular and macrovascular complications. Evidence suggests that people who smoke with diabetes may need higher doses of insulin and oral hypoglycaemic agents to achieve similar glycaemic control compared to non-smokers, though individual responses vary.
Furthermore, smoking is associated with increased central (visceral) adiposity—fat accumulation around the abdomen—which is independently linked to insulin resistance and poorer metabolic outcomes. The carbon monoxide in cigarette smoke reduces oxygen-carrying capacity in the blood, compounding the tissue hypoxia that can already occur in diabetes due to impaired circulation. This creates a particularly harmful environment for wound healing and increases susceptibility to infections—both significant concerns for people living with diabetes.
Whilst you can physically smoke with type 2 diabetes, the clinical evidence overwhelmingly demonstrates that doing so substantially worsens disease control and accelerates complications. NICE and NHS guidance consistently identify smoking cessation as a critical intervention for improving outcomes in diabetes management, alongside glycaemic control, blood pressure management, and lipid control.
Risks of Smoking with Type 2 Diabetes
The combination of smoking and type 2 diabetes creates a synergistic risk profile that substantially increases the likelihood of serious health complications. Cardiovascular disease represents the most significant threat: individuals with diabetes who smoke face a markedly higher risk of dying from cardiovascular causes compared to non-smoking people with diabetes. This elevated risk encompasses myocardial infarction, stroke, and peripheral arterial disease, all of which tend to occur at younger ages and with greater severity in this population.
Microvascular complications are similarly accelerated by smoking. Diabetic retinopathy, which can lead to vision loss and blindness, may progress more rapidly in smokers due to the combined effects of hyperglycaemia and smoking-induced vascular damage. Diabetic nephropathy (kidney disease) may also advance more quickly, with smokers facing a higher risk of progressing to end-stage renal disease requiring dialysis. The risk of diabetic neuropathy—nerve damage causing pain, numbness, and loss of sensation—is increased, particularly affecting the feet and lower limbs.
Peripheral vascular disease and foot complications pose especially serious risks. Smoking severely impairs blood flow to the extremities, and when combined with diabetes-related neuropathy and impaired immune function, this creates ideal conditions for foot ulcers, infections, and tissue necrosis. People with diabetes who smoke face a significantly elevated risk of lower limb amputation compared to non-smokers with diabetes.
Additional risks include:
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Increased susceptibility to infections, particularly respiratory infections
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Poorer wound healing following surgery or injury
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Higher rates of erectile dysfunction in men
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Greater risk of developing diabetes-related complications at a younger age
Urgent foot problems: If you develop a new foot ulcer, spreading infection, severe pain, colour change, or a cold foot, seek same-day assessment through your diabetes foot protection team or urgent care service, as recommended by NICE guidance.
The NHS and NICE emphasise that smoking cessation is a key modifiable risk factor in reducing these complications, alongside good blood glucose, blood pressure, and cholesterol control.
Benefits of Quitting Smoking for Diabetes Management
Stopping smoking delivers substantial and measurable benefits for people with type 2 diabetes, with improvements beginning within hours of the last cigarette and continuing to accrue over months and years. Immediate cardiovascular benefits include normalisation of heart rate and blood pressure within 20 minutes, and improved circulation within 2–12 weeks. Carbon monoxide levels in the blood return to normal within 24–48 hours, enhancing oxygen delivery to tissues—particularly important for wound healing and reducing infection risk in diabetes.
Glycaemic control may improve over the longer term after quitting, though individual responses vary. Some people experience temporary fluctuations in blood glucose in the weeks after stopping, partly due to modest weight gain. However, studies demonstrate that former smokers can achieve better HbA1c levels (the key measure of long-term blood sugar control) compared to continuing smokers over time. Insulin sensitivity may gradually improve as the inflammatory effects of smoking subside, potentially allowing for reduction in diabetes medication doses in some individuals. Importantly, the substantial cardiovascular and vascular benefits of quitting far outweigh any short-term effects on weight or glucose.
Long-term risk reduction is profound. Within 1 year of quitting, the excess risk of coronary heart disease is reduced by approximately half in the general population. After 5 years, stroke risk approaches that of non-smokers. The progression of diabetic kidney disease may slow, and the risk of vision-threatening retinopathy may decrease. For those with existing peripheral vascular disease, quitting smoking substantially reduces the risk of amputation and improves outcomes if surgical intervention becomes necessary.
Additional benefits include:
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Potentially enhanced effectiveness of diabetes medications, which may allow dose reductions over time
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Improved immune function and reduced infection rates
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Better response to physical activity, supporting weight management and fitness
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Reduced healthcare costs through fewer complications and hospitalisations
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Improved quality of life, including better energy levels and physical functioning
NICE guidelines emphasise that smoking cessation represents one of the most cost-effective interventions in diabetes care, with benefits that extend well beyond glucose control to encompass overall health and longevity.
NHS Support for Stopping Smoking with Type 2 Diabetes
The NHS provides comprehensive, evidence-based support for smoking cessation specifically tailored to individuals with long-term conditions such as type 2 diabetes. NHS stop smoking services are available free of charge throughout the UK and offer the highest success rates for quitting—people using specialist stop smoking services with pharmacotherapy are around three times more likely to quit successfully compared to unaided attempts. These services can be accessed through GP surgeries, community pharmacies, and dedicated stop smoking clinics. You can find your local service via the NHS website or by contacting your local authority public health team.
Your GP or practice nurse should routinely discuss smoking status at diabetes review appointments and can provide personalised advice, prescribe smoking cessation medications, and refer you to specialist services. Many diabetes specialist nurses have additional training in smoking cessation and understand the specific challenges faced by people with diabetes, including concerns about weight gain and blood sugar fluctuations during the quitting process.
Pharmacological support available through the NHS includes:
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Nicotine replacement therapy (NRT): Available as patches, gum, lozenges, inhalators, nasal spray, or mouth spray. These products are safe for people with diabetes and can be prescribed or purchased over the counter. Combination NRT (using two products simultaneously) increases success rates. Check the patient information leaflet or speak to your pharmacist about correct use.
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Varenicline: A prescription medication that reduces cravings and withdrawal symptoms by partially stimulating nicotine receptors in the brain. It is effective for people with diabetes, though blood glucose should be monitored as smoking cessation itself may affect control. Dose adjustment is needed in severe renal impairment. Availability may vary locally; consult your GP. Refer to the MHRA Summary of Product Characteristics (SmPC) via the electronic Medicines Compendium (EMC) for full prescribing information.
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Bupropion: An alternative prescription medication that reduces cravings. It is contraindicated in people with a history of seizures or eating disorders and requires caution in certain other conditions. Consult the MHRA SmPC for full safety information.
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Nicotine e-cigarettes: NICE supports offering nicotine-containing e-cigarettes as an option to help people stop smoking. E-cigarettes are substantially less harmful than smoking, though not risk-free. Discuss this option with your stop smoking adviser or healthcare professional.
Digital and telephone support includes the NHS Quit Smoking app, which provides daily support, tracks progress, and offers motivational messages. The NHS Smokefree helpline (0300 123 1044) provides free, confidential advice from trained advisers who can discuss concerns specific to diabetes management.
Your diabetes care team should work collaboratively with smoking cessation services to monitor blood glucose levels during the quitting process, as medication adjustments may be needed. This integrated approach ensures that stopping smoking enhances rather than complicates your diabetes management.
Reporting side effects: If you experience a suspected side effect from any smoking cessation medicine, you can report it via the MHRA Yellow Card scheme at yellowcard.mhra.gov.uk or by searching for 'MHRA Yellow Card' in the Google Play or Apple App Store.
Managing Blood Sugar Levels After Quitting Smoking
Blood glucose management requires careful attention during and after smoking cessation, as the metabolic changes that occur can affect diabetes control in both predictable and individual ways. In the initial weeks after quitting, some people experience temporary fluctuations in blood sugar levels as the body adjusts to the absence of nicotine's effects on insulin resistance and stress hormone release. Generally, insulin sensitivity may improve, which can lead to lower blood glucose readings—this is a positive development but may necessitate medication adjustments to prevent hypoglycaemia.
Monitoring should be intensified during the first 4–8 weeks after quitting. If you use insulin or sulfonylureas (such as gliclazide), which carry a risk of hypoglycaemia, check your blood glucose more frequently than usual—ideally before meals and at bedtime. Keep a record of readings and note any patterns of unexpectedly low values. Contact your diabetes nurse or GP if you experience readings below 4 mmol/L or have symptoms of hypoglycaemia (shakiness, sweating, confusion, or palpitations). Your healthcare team may need to reduce medication doses as your insulin sensitivity improves. Arrange a proactive review with your diabetes team around 4–8 weeks after quitting to adjust therapy as needed.
Weight management represents a common concern, as modest weight gain (typically 2–5 kg) often occurs after quitting smoking due to increased appetite and changes in metabolism. For people with type 2 diabetes, this can temporarily affect glycaemic control. However, the cardiovascular and metabolic benefits of quitting far outweigh the risks associated with modest weight gain. Strategies to minimise weight gain include:
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Maintaining regular meal patterns with balanced portions of complex carbohydrates, lean protein, and vegetables
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Choosing healthy snacks such as fruit, raw vegetables, or unsalted nuts when cravings occur
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Increasing physical activity gradually, which also helps manage blood sugar and reduces stress
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Staying well hydrated with water or sugar-free drinks
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Using sugar-free gum or mints to manage oral cravings without affecting blood glucose
Long-term glucose control may improve in the months following successful smoking cessation, with some studies showing that HbA1c levels tend to decrease, reflecting better overall glycaemic control. This improvement may allow for simplification of your diabetes medication regimen over time, though any changes should only be made in consultation with your healthcare team.
When to seek advice: Contact your GP or diabetes nurse if you experience persistent hypoglycaemia, unexplained hyperglycaemia (readings consistently above 15 mmol/L), significant weight gain (more than 5 kg in 3 months), or difficulty managing your diabetes during the quitting process. Seek urgent medical advice if you feel unwell with very high glucose levels (for example, above 20 mmol/L), signs of dehydration, confusion, or if you have elevated capillary ketones; follow your sick-day rules if applicable. Your healthcare team can provide tailored advice, adjust medications appropriately, and refer you to a dietitian if needed. Remember that the temporary challenges of adjusting diabetes management while quitting smoking are far outweighed by the substantial long-term health benefits of becoming smoke-free.
Frequently Asked Questions
Does smoking make it harder to control blood sugar with type 2 diabetes?
Yes, smoking significantly impairs blood sugar control in type 2 diabetes by increasing insulin resistance and triggering stress hormones that interfere with glucose metabolism. People who smoke with diabetes often require higher doses of medication to achieve similar glycaemic control compared to non-smokers, and may experience persistently elevated HbA1c levels despite treatment.
What happens to my diabetes if I keep smoking?
Continuing to smoke with type 2 diabetes substantially increases your risk of serious complications including heart attack, stroke, kidney failure, vision loss, nerve damage, and lower limb amputation. Smoking accelerates damage to blood vessels throughout the body, worsens circulation, impairs wound healing, and causes complications to develop earlier and progress more rapidly than in non-smokers with diabetes.
Will I gain weight if I stop smoking with diabetes?
Modest weight gain of 2–5 kg commonly occurs after quitting smoking due to increased appetite and metabolic changes, which may temporarily affect blood sugar control. However, the substantial cardiovascular and metabolic benefits of quitting far outweigh the risks of modest weight gain, and strategies such as balanced eating, regular physical activity, and healthy snacking can help minimise weight changes during the quitting process.
How quickly will my health improve after I quit smoking with type 2 diabetes?
Health improvements begin within hours of quitting: heart rate and blood pressure normalise within 20 minutes, carbon monoxide levels return to normal within 24–48 hours, and circulation improves within 2–12 weeks. Long-term benefits include reduced cardiovascular risk by half within 1 year, potential improvements in HbA1c levels, slowed progression of kidney and eye complications, and substantially lower amputation risk.
Can I use nicotine replacement therapy or vaping if I have diabetes?
Yes, nicotine replacement therapy (patches, gum, lozenges, sprays) and nicotine e-cigarettes are safe and effective options for people with type 2 diabetes who want to stop smoking. These products are substantially less harmful than continuing to smoke, and NICE guidance supports their use as part of a comprehensive quit plan, ideally combined with support from NHS stop smoking services.
Where can I get free help to stop smoking with type 2 diabetes?
NHS stop smoking services are available free throughout the UK via GP surgeries, community pharmacies, and dedicated clinics, offering the highest success rates for quitting. Your GP or diabetes nurse can prescribe smoking cessation medications, refer you to specialist services, and monitor your blood glucose during the quitting process to adjust diabetes medications as needed.
The health-related content published on this site is based on credible scientific sources and is periodically reviewed to ensure accuracy and relevance. Although we aim to reflect the most current medical knowledge, the material is meant for general education and awareness only.
The information on this site is not a substitute for professional medical advice. For any health concerns, please speak with a qualified medical professional. By using this information, you acknowledge responsibility for any decisions made and understand we are not liable for any consequences that may result.
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