People with type 1 diabetes (T1D) use alcohol and marijuana just as often as the general population, but discussions of the unique risks and mitigation strategies don’t often happen in clinical encounters.

“Substance use can impact diabetes management and long- and short-term complications,” said Alissa Jeanne Curda Roberts, MD, associate professor in the Division of Endocrinology and Diabetes at Seattle Children’s Hospital in Seattle, speaking at the American Diabetes Association (ADA) 2026 Scientific Sessions.

For example, alcohol can increase the risk for hypoglycemia, and cannabis can lead to hyperglycemia due to appetite stimulation, she explained.

But rather than simply advising people with T1D not to use alcohol or cannabis, or to stop using, Jeremy H. Pettus, MD, who also spoke at the session, offered advice and information for counseling both youth and adults with T1D who do use alcohol and/or marijuana about how to minimize their unique risks.

“Most people do drink alcohol” and we need to address it, said Pettus, an adult endocrinologist and associate professor of medicine at UC San Diego. He also noted that millions of people use marijuana.

Prevalence and Risk for Substance Abuse in T1D

Roberts summarized a study showing that while substance use in younger teens with T1D may lag behind their peers, by 11th and 12th grade the rates are roughly equal.

And in another study examining youth aged 9-18 years with different chronic medical conditions, one third with T1D reported past-year alcohol use, with half reporting binge drinking. One quarter reported using marijuana in the past year.

“Adolescents with [T1D] are just as likely to use substances as their peers,” said Roberts. “And unfortunately, having [T1D] and being an adolescent really just complicates these things.”

These rates are much higher in adults, she noted. In one study of 936 adults (mean age, 38 years) with T1D, past-year alcohol use was reported by 79%, past-month use by 63%, and daily or near-daily use by 9%. Binge drinking was present in 19%. Marijuana use was reported by 18%. “This really aligns with what we’ve seen in the general US population,” Roberts said.

Alcohol Use in T1D: Watch Out for Hypoglycemia

Alcohol consumption can lead to increased risk for hypoglycemia because it inhibits gluconeogenesis, reduces hypoglycemia awareness, and impairs counter-regulatory hormones. Hypoglycemia symptoms can include slurred speech, confusion, dizziness, impaired coordination, loss of consciousness, seizure, and death.

“These symptoms have a lot of overlap with alcohol intoxication and can be very easily confused and misunderstood, which can lead to delay of identification and delay of proper treatment,” Roberts cautioned.

Moreover, that increased hypoglycemia risk can last up to 24 hours after alcohol consumption.

While some have suggested that glucagon may be less effective in treating hypoglycemia in the setting of alcohol given the liver effect, “other than the theoretical risk, I couldn’t really find studies to support that,” said Roberts. “It may not be quite as effective as it would be without alcohol on board but still worthwhile using.”

Not All Alcohols Are Alike

Pettus noted that some alcohols can have a “one-two punch” effect on blood sugar. Carbohydrates in certain alcohols raise blood sugar in the short-term, while the alcohol itself lowers blood sugar in the longer term. But, he added, types of alcohol vary widely by carb content and thus will have dramatically different short-term effects on blood sugar.

For example, a 12-oz beer contains about 180 calories and about 15 g of carbs, although this can vary — an ultralight beer might have about 4 g of carbs, whereas a heavier India Pale Ale might have 20-30 g. “So that’s obviously going to raise your blood sugar acutely,” Pettus said.

On the other hand, a 5-oz glass of wine contains about 120 calories but only about 5 g of carb, whether white or red. “It doesn’t really matter so much. Wine in general is pretty diabetes friendly,” he said.

But the “best” drink in terms of maintaining steady blood sugars is a shot, at about 69 calories and 0 g of carbs, said Pettus. “If you’re just drinking straight-up alcohol — whiskey or vodka, or whatever you want — there are no carbs in that.”

On the far opposite side are the fancy drinks with sugar added, such as daiquiris or piña coladas, which can contain over 500 calories and over 60 g of carbs. “Those things are really going to spike your blood sugars,” he noted.

Safety Tips for Drinking With T1D

In the longer term, the effects of alcohol itself can make people with T1D particularly vulnerable to hypoglycemia overnight. In order to avoid that, Pettus offered some tips:

• Always eat before drinking. He advises patients with T1D to eat something with protein and fat to smooth out blood sugars overnight.
• Avoid sugary drinks. “I’m not saying don’t ever have them…. But if you’re drinking them, know that they’re going to put you on that roller coaster and make it a lot harder to control your blood sugars.”
• Bolus for beer but not hard alcohol or wine.
• Crank up the continuous glucose monitor (CGM) alarms. Instead of setting the low alarm at 55 mg/dL, put it up to 80 mg/dL or 90 mg/dL. And if possible, share your CGM data with someone trustworthy (and sober).
• Do your diabetes tasks before you go out. “I like to say protect yourself from drunk you later…. If you know you need to change your infusion set, don’t decide to do it when you get home. You’re not going to want to then,” Pettus cautioned.
• Get a drinking buddy who is aware that you have diabetes and what to do in case of emergency.
• Consider smaller boluses the next day. Having had more than about three drinks the night before can lead to greater insulin sensitivity the next day and higher risk for hypoglycemia.

In addition to this list, Pettus added that it might be a good idea to aim for a target blood sugar of 160-200 mg/dL while drinking. But “this is the ‘Jeremy rule,’” he said (referring to himself) and has “absolutely no scientific proof.”

“The point here,” he explained, “is to tolerate some hyperglycemia to avoid hypoglycemia when you’re drinking.”

Pettus is the director of T1D education for the nonprofit educational group called Taking Control of Your Diabetes (TCOYD). Along with the organization’s founder/director Steven V. Edelman, MD, the two made a lighthearted video explaining the effects of alcohol on diabetes. In it, they both drink alcohol to illustrate what it does to their blood sugars because both have T1D themselves.

It’s the most watched of all TCOYD’s educational videos, Pettus said.

“There’s a thirst for information out there,” he noted. “Nobody’s going to ask their doctor how can I drink. I think there’s just this assumption that you have to be ‘good’ and not drink.”

Cannabis in Diabetes: Hyperglycemia due to the Munchies, Other Risks

Roberts said that with cannabis use, appetite stimulation (aka “the munchies”) can lead to hyperglycemia, whereas impaired judgment can lead to insulin omission or incorrect dosing in either direction. In one study of 164 adolescents with T1D, 23% reported prior cannabis use. All were aware that they should monitor their blood glucose while consuming cannabis, but only 86% said they actually did, while 14% admitted to forgetting to take their insulin while “high.”

Whether cannabis has a direct effect on glycemia is unclear because some studies have suggested it increases insulin sensitivity in some tissues, while promoting insulin resistance in others, Roberts noted.

In the T1D Exchange registry, cannabis use was associated with a twofold increased risk for diabetic ketoacidosis (DKA) among adults with T1D.

And in the recently recognized “hyperglycemic ketosis due to cannabis hyperemesis syndrome,” chronic heavy cannabis use leads to severe nausea and vomiting, followed by hyperglycemia and ketosis. “It can look a lot like DKA, but here the patient is alkalotic rather than acidotic,” she explained.

The syndrome is often unresponsive to antiemetics, but interestingly, hot showers reduce the symptoms in some patients. Actual treatment includes stopping the cannabis, providing hydration, and giving insulin therapy to correct ketosis. “This is something we may be seeing more of, now that cannabis seems to be a more commonly used substance in our population,” Roberts commented.

Pettus noted that only recently, in April 2026, marijuana was reclassified from Schedule I — the most dangerous — to Schedule III, making it much more available for medical research. Prior to the reclassification, and after about 3 years of regulatory red tape, he obtained a grant for a prospective placebo-controlled trial on the effect of marijuana on glucose and other metabolic parameters in people with type 2 diabetes.

“I’m really thankful that this has been reclassified,” he said. “I think it means we’re going to get an appropriate flood of testing on what this drug does.” Despite how many people use marijuana, “we have zero clue what it does metabolically.”

Pettus concluded with his “JEREMY System” for marijuana use with T1D:

J: Just know how much you are smoking/eating, etc.

E: Engage your diabetes “tasks” before you get high, just as with alcohol.

R: Remember to wear your CGM.

E: Emesis (vomiting) means you need to go to the emergency department if you can’t hydrate.

M: Munchies still count as carbs, so bolus!

Y: You need to be more responsible than most, so take care of yourself!

Roberts and Pettus had no disclosures.

Miriam E. Tucker is a freelance journalist based in the Washington, DC, area. She is a regular contributor to Medscape, with other work appearing in The Washington Post, NPR’s Shots blog, and diaTribe. She is on X @MiriamETucker and BlueSky @miriametucker.bsky.social.