Alcohol does not always raise blood sugar. Its effect depends on how much you drink, what type of drink it is, whether you drink with food, and whether you have diabetes or take glucose-lowering medicines.
Some alcoholic drinks contain carbohydrates or added sugar, which can cause blood sugar to rise soon after drinking. Heavy or long-term alcohol use can also worsen insulin resistance and raise average blood sugar over time, increasing the risk of type 2 diabetes or making diabetes harder to control.
Alcohol can also lower blood sugar, especially when taken on an empty stomach or after fasting. This happens because the liver has to process alcohol and may release less glucose into the blood. In people using insulin or certain diabetes medicines, this can increase the risk of delayed low blood sugar, including overnight.
If you have diabetes, prediabetes, liver disease, or take medication for blood sugar, ask your doctor or endocrinologist what amount, if any, is safe for you. Avoid self-adjusting diabetes medication around alcohol, and do not drink on an empty stomach.