Nicotine can significantly impact your blood sugar levels. It can cause your blood sugar to either increase or decrease. This happens because nicotine changes the way your body uses glucose, the sugar in your blood that fuels your cells. For people with diabetes, nicotine can make the condition worse by causing severe low blood glucose (hypoglycemia) if they are taking insulin. Nicotine leads to insulin resistance, a condition where your cells don't respond well to insulin and can't take glucose out of your blood for energy. This results in higher blood sugar levels. Additionally, nicotine can increase the production of triglycerides, a type of fat linked to insulin resistance, and raise levels of hormones that counteract insulin. Smoking, the most common way to consume nicotine, can quickly affect your cells' ability to use insulin, leading to insulin resistance within an hour. Studies show that people with diabetes who smoke need larger doses of insulin to control their blood glucose. High blood glucose over several years can lead to heart disease, kidney damage, nerve damage, and eye problems. Smoking increases the risk of developing type 2 diabetes by 30% to 40%, and smoking more than 20 cigarettes a day almost doubles this risk. Other forms of nicotine consumption can also raise blood glucose levels. If you quit smoking, you might experience a temporary increase in insulin resistance due to weight gain, but this usually improves after a couple of months. If you don't have diabetes, quitting smoking can initially increase your risk of developing type 2 diabetes, especially in the first two years, often due to weight gain. However, after two years, the risk starts to decrease, and after 12 years, it equals that of someone who never smoked.