Based on NIH | Does drinking alcohol increase the risk of hypoglycemia in people with diabetes?

Yes drinking alcohol can increase the risk of hypoglycemia (low blood glucose) in people with diabetes, both shortly after drinking and for many hours afterward. This happens because the liver prioritizes breaking down alcohol over releasing glucose into the bloodstream, which can blunt the body’s natural safety net against falling sugars, especially when insulin or certain diabetes pills are on board. ^{[1] [2]}

Why alcohol can cause low blood sugar

• Liver “traffic jam”: The liver normally releases stored sugar (glycogen) and makes new glucose (gluconeogenesis) to keep levels stable. When alcohol is present, the liver shifts to metabolizing alcohol and may not release or produce enough glucose, allowing blood sugar to drop. ^{[1] [3]}
• Medication interactions: Alcohol’s glucose‑lowering effect adds to the effects of insulin and sulfonylureas (like glipizide, glyburide), increasing the chance of hypoglycemia. ^{[2] [4]}
• Delayed lows: The risk isn’t just immediate; lows can occur overnight and into the next day after evening drinking, even with “usual” amounts. ^{[5] [6]}

What the evidence shows

• Guidance from major diabetes organizations notes that hypoglycemia is the primary concern when alcohol is combined with diabetes treatments, particularly insulin and sulfonylureas. ^{[2] [4]}
• Clinical studies show morning blood glucose can be significantly lower after evening alcohol intake in people with type 1 diabetes, with more hypoglycemic episodes the next morning. ^[6]
• Experimental data indicate that moderate alcohol can reduce awareness of hypoglycemia, making it harder to recognize lows even when the body is showing signs this can delay treatment. ^[7]
• Patient education materials emphasize that the risk of low blood sugar can persist for hours after the last drink, and increases with higher alcohol intake or drinking without food. ^{[5] [8]}

Who is at higher risk

• People using insulin or sulfonylureas have a heightened risk due to additive effects on blood glucose lowering. ^{[2] [4]}
• Those who drink on an empty stomach, exercise after drinking, or have depleted glycogen stores (e.g., after fasting or heavy activity) are more susceptible to delayed hypoglycemia. ^{[2] [9]}
• Older adults or individuals with malnutrition may have more pronounced hypoglycemic responses to sulfonylureas, especially when alcohol is involved. ^[10]

Practical safety tips

• Eat when you drink: Having alcohol with a meal or carbohydrate snack helps buffer falling glucose and reduces delayed lows. ^{[5] [2]}
• Don’t drink on an empty stomach: Drinking without food significantly raises hypoglycemia risk. ^{[5] [2]}
• Check glucose more often: Monitor before drinking, during, a few hours after, and up to 24 hours later; confirm safe levels before sleep. ^[8]
• Avoid exercising after alcohol: Activity plus alcohol further lowers glucose and raises hypoglycemia risk. ^[9]
• Carry ID and avoid drinking alone: Symptoms of intoxication and hypoglycemia can look similar; companions who know your diabetes can help. ^[9]
• Discuss with your clinician: Get personalized advice on alcohol limits and potential medication adjustments, especially if you use insulin or sulfonylureas. ^{[1] [2]}

Recognizing and responding to lows

• Common signs include shakiness, sweating, fast heartbeat, hunger, headache, irritability, blurred vision, and confusion; however, alcohol can dull awareness of these symptoms. ^{[11] [7]}
• Treat promptly with fast‑acting carbohydrates (e.g., glucose tablets or juice) and recheck levels; do not delay assuming it is “just the alcohol.” ^[11]
• Before bed after drinking, consider a snack if your glucose is trending lower, and set an alarm or use continuous glucose monitoring alerts if available. ^[8]

Special medication notes

• Insulin and sulfonylureas: Alcohol increases hypoglycemia risk through additive effects; individualized dose guidance may be needed around drinking occasions. ^{[2] [4]}
• Metformin: Alcohol does not typically cause hypoglycemia with metformin alone, but excessive alcohol with metformin raises the risk of lactic acidosis; moderation and caution are advised. ^{[12] [13]}

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Key takeaways

• Alcohol can cause immediate and delayed hypoglycemia by limiting the liver’s ability to release or make glucose. ^{[1] [3]}
• The risk is highest when alcohol is combined with insulin or sulfonylureas, when drinking on an empty stomach, or after exercise. ^{[2] [9]}
• Monitor closely for up to 24 hours after drinking, eat when you drink, avoid exercising after alcohol, and have a plan to treat lows. ^{[8] [9]}

Responsible, informed choices and glucose monitoring can lower your risk while maintaining safety if you choose to drink. ^{[1] [2]}