Alcohol and Caffeine: How Do They Interact Together? 

Melissa Bennett-Heinz
LCSW, Gestalt Psychotherapist

Self Help

Combining alcohol and caffeine is not a new occurrence - people have been combining the two substances since the mid-19th century. You will know these older combinations as Irish coffee, rum and coke, and Buckfast Tonic Wine. While combining these two substances is not medically recommended, let’s break down the facts about combining alcohol and caffeine. 

First, let’s look at how caffeine affects the mind and body. Caffeine is a stimulant and when ingested, caffeine can have several effects. Caffeine impacts the central nervous system by suppressing a chemical naturally produced in our bodies called adenosine. Normally, throughout the day, adenosine is slowly released and builds which is what causes us to become sleepy at night. Caffeine works to block this action in the brain. It also stimulates dopamine and serotonin, two other natural chemicals found in our bodies, responsible for our mood, as well as adrenaline, which is responsible for energy levels. Caffeine also acts as a diuretic leading to a more frequent need to urinate. In higher doses, caffeine can lead to side effects such as anxiety, elevated heart rate, restlessness, muscle tremors, and digestive issues.  

Alcohol has the opposite effect as it depresses the central nervous system, meaning, it slows the brain down. It works directly on the same chemical in our body, adenosine, causing it to accumulate faster and has the effect of causing one to feel drowsy. It also causes a release in the chemical, GABA, in our brain, which impacts sleep and relaxation. Other neurotransmitters that are affected include serotonin and dopamine, which affect your mood. Alcohol's depressant action also limits your ability to think clearly and reason, slows motor function and coordination, and leads to a loss of physical sensations. 

When you mix the two substances, the primary effect is the sedative effects of alcohol are reduced. Caffeine can combat the drowsiness that often comes with consuming alcohol, but it will not impact the way alcohol affects things like your judgment or motor skills. Your decision-making and coordination will be just as impaired, and decision-making and judgment will be reduced. The only difference is you may not realize it because the caffeine makes you feel more awake.

People mix caffeine and alcohol for a variety of reasons. Some may simply like the way combining two particular things tastes and aren't intentionally combining caffeine and alcohol for effect. Others intentionally combine the two substances with purpose. The few main reasons why people combine caffeine with alcohol are: 

  • Enjoy the taste
  • Desire to mask the taste of the alcohol
  • To feel like they can consume more alcohol when combining  
  • Believe it will stave off a hangover

Yes, it is possible to mix caffeine and alcohol. It is important to be aware of the side effects and potential risks that consuming the two drugs may have on your body. When combining caffeine and alcohol, you may experience increased alertness, which may mask the effects the alcohol is having on your body. If you don't feel the effects of the alcohol, you may drink more than is safe potentially leading to more risk-taking behaviors, increased heart rate and blood pressure, increased dehydration, and impaired judgment. It is important to understand your tolerance as well as the potential impact of mixing caffeine and alcohol.

While it is possible to mix energy drinks with alcohol together, it is important to be aware of the potential risks associated with combining the two. Energy drinks not only contain high amounts of caffeine, but they may also contain other ingredients that have stimulant effects on the body. Here are a few things you may want to keep in mind when choosing to drink these together:

  • Increased heart rate and blood pressure due to the stimulating effects
  • Dehydration as energy drinks and alcohol act as diuretics
  • Adverse side effects on the central nervous system may lead to severe intoxication and alcohol poisoning. 
  • Heightened alertness may lead you to overdrink

Drinking caffeinated alcoholic drinks can have various effects on both the body and mind. Caffeine is a stimulant that leads to increased alertness making you feel more awake. When combined with alcohol, caffeine can mask the effects of the alcohol making you feel less impaired than you are. Caffeine is widely known to increase blood pressure and heart rate adding stress on your cardiovascular system leading to irregular heartbeat and other health-related issues. Caffeinated alcoholic beverages will dehydrate you at a more rapid rate than either on their own and lead to headaches, dizziness, and fatigue. Sleep may also be altered as consuming caffeine and alcohol may disrupt normal sleep patterns. 

There are many misconceptions about consuming alcohol and caffeine. First, consuming alcohol and caffeine makes you less drunk. This couldn’t be more wrong. Combining alcohol and caffeine does not make you immune to the effects of alcohol on your system, it only makes you feel more awake. It can mask the sedative effects of alcohol and lead to underestimating your level of intoxication which can lead to engaging in more risky behaviors and increased risk of alcohol-related harm. Next, mixing caffeine with alcohol will prevent a hangover. Caffeine may make you feel more alert and awake, but it does not counteract the blood alcohol concentration or level of impairment. The third biggest misconception is caffeine can counteract the negative effects of alcohol. While it does counteract the sedative effects, it does not eliminate or mitigate the consequences of excessive alcohol consumption. It does provide people with a sense of false confidence which can lead to increased risk-taking behaviors. Another big misconception is that caffeine will sober you up after overconsumption of alcohol. There is no remedy other than time. 

Combining caffeine and alcohol can lead to increased harm. Since combining the two may cause you to feel more alert and mask the effects of the alcohol, it is easier to consume larger quantities of alcohol than what you can safely tolerate and process. This may lead to thinking you are more invincible and/or less impaired than you are, poor decision-making, impaired cognitive function, and an inability to exercise good judgment. There is a much greater chance of engaging in risk-taking behaviors such as unprotected sex, drunk driving, or other alcohol-related accidents. There are negative effects on your body including increased stress on your heart, and excessive dehydration leading to headaches, and dizziness. 

Coffee will not sober you up after drinking alcohol. This is purely a myth. The caffeine in coffee may cause you to feel more awake and alert, leading you to believe you are more “sober,” but this is all it will do. The only thing that sobers you up is time. Your body needs time to metabolize and process the alcohol you have consumed.

When choosing to mix caffeine and alcohol, there are several symptoms that one should watch out for. First, increased heart rate and heart palpitations sometimes can be felt and accompanied by feelings of anxiety or discomfort. Two, dehydration as both caffeine and alcohol are diuretics, meaning they can both increase urine production, which may contribute to dehydration. Symptoms of dehydration are dizziness, fatigue, dry mouth, and thirst. Next, restlessness or insomnia. Caffeine is a stimulant and can make it difficult to relax or go to sleep. When combined with alcohol, it can exacerbate even further disrupted sleep which can lead to restlessness and insomnia. Four, intoxication misperception. Combining the caffeine with the alcohol may cause you to feel more awake and alert, and mask the symptoms of sedative effects of alcohol which may lead to overconsumption of alcohol. Five, gastrointestinal issues may arise such as upset stomach and acid reflux. And lastly, mixing caffeine and alcohol may lead to behavioral changes such as restlessness, aggression, impulsivity, or difficulty controlling emotions. 

Consuming alcohol with caffeine may cause you to feel more drunk than you are. This occurs because the stimulant effects of the caffeine negate the sedative effects of the alcohol. You may not be able to feel the actual effect of the alcohol entering your body and the drug taking effect. This happens because the chemical in your brain, called adenosine, which increases with alcohol and causes sedation, is blocked with the ingestion of caffeine. 

Most people can tell when they’ve reached their limit with alcohol. This is commonly referred to as tolerance. The average person can safely process one alcoholic drink per hour. Most people know when to stop drinking because they feel the effects the alcohol has on their system and this is a cue that they've had enough. When you also mix caffeine with alcohol, you will not feel the effects in the same way or at all this leading to overconsumption.

The risk of alcohol poisoning increases when combining alcohol with caffeine. Since caffeine masks the effects of the sedative effect of alcohol, many people don’t realize how much they have consumed. Being more alert could also lead you to feel like you are fine to drink more. However, caffeine does not speed up the metabolism of alcohol. Therefore, if you continue to drink, your blood alcohol level will continue to rise even though you may not feel the effects.  

Mixing caffeine and alcohol can increase the likelihood of misusing alcohol in several ways. First, increased alertness as a result of the effects of the stimulant that is in caffeine reduces the perception of impairments caused by alcohol and makes you think you’re less intoxicated than you are. This can result in consuming more alcohol than intended. Second, the caffeine also reduces feeling the depressant/sedative effects of the alcohol that cause fatigue. With delayed fatigue and feeling more awake, you may also feel capable of consuming more. Third, the masked effects of alcohol by the caffeine leads one to believe they are less impaired than they are. This misperception can lead to excessive alcohol consumption and engaging in more risk-taking behaviors. Lastly, combining alcohol and caffeine can increase the amount of time you spend drinking. Since the effects are not felt in the same way, you may think you can stay and drink for longer periods consuming more alcohol which potentially leads to the same outcome as excessively drinking. 

Regularly consuming alcohol and caffeine together increases the risk of alcohol dependence. The more frequently you binge or over-drink, the greater your chances of developing alcohol dependence. This risk goes up even higher if you have a family history of alcohol addiction. Alcohol dependence is the continued use of alcohol despite it causing significant problems in your life. If you become dependent on alcohol, It means your body has gotten so used to the presence of alcohol that it needs it to function. At this point, if your body doesn’t have it, withdrawal begins which can include a wide range of symptoms including a change in all vital signs, seizures, psychosis, and potentially death.

Mixing caffeine and alcohol can impair your ability to think clearly and impair judgment. With this impaired judgment, people do things they wouldn’t normally do such as getting in the car with a drunk driver, taking advantage of someone sexually, engaging in unprotected sex, harming someone else, and getting into fights. 

There is a wide range of short- and long-term consequences associated with alcohol misuse. For a few individuals, any amount of drinking could be potentially harmful. Some common alcohol-related consequences are social, educational, and vocational disruptions, work-related issues, relationship conflicts, health and mental health issues, and legal and financial consequences. 

Common alcohol-related consequences include:

  • Medical emergencies, such as alcohol overdose
  • Alcohol-related medical emergencies such as falls or car accidents
  • Loss of employment
  • Loss of friends
  • Breakup with a boyfriend or girlfriend
  • Financial consequences
  • Legal Consequences such as public intoxication, driving under the influence, assault, and battery
  • Health issues such as liver problems, hypertension, cardiac issues
  • Alcohol Dependence

Mixing caffeine with alcohol poses an increased risk of overconsumption and misuse of alcohol, even alcohol poisoning and overdose, and it is important to take this seriously. 

Alcohol overdose can have permanent and lasting effects and even lead to death. You may need medical attention. It is better to seek medical care and not need it rather than need it and not have to receive medical intervention. If you or someone you know is showing any of the following overdose signs, call 911: 

  • Seizures
  • No gag reflex
  • Difficulty staying awake
  • Change in mental state, including confusion
  • Breathing that’s not regular - when there’s a gap of 10 seconds or more between breaths
  • Slowed breathing - fewer than 8 breaths per minute
  • Hypothermia or low body temperature
  • Unconsciousness or passing out
  • Skin that looks grey, blue, or pale

If you like to drink rum and coke and decide you still want to enjoy this beverage, there are ways to reduce the symptoms and cope. Here are a range of strategies you can try to employ: 

  • Slow your drinking down, sip, don’t gulp
  • Switch to water or a non-alcoholic beverage in between drinks
  • Limit consumption to one drink per hour
  • Decide before you drink, how much you are going to drink and stick to it.
  • Switch bars and don’t just stay in the same bar (make sure to have a sober driver or use UBER)
  • Stay hydrated and order a glass of water (and drink it) with each drink you consume
  • Limit drinking with friends who have a habit of partying hard and getting drunk
  • Order food or appetizers while you drink
  • Go to a bar with a pool table, dart board, or ping pong and keep busy with activity while drinking

If you think you may have a problem related to alcohol, Alcoholics Anonymous is a great resource that you can use to find out if you belong there or not? There are meetings both online and in person that are classified as “open,” meaning anyone can attend, you don’t need to identify as dependent on drugs or alcohol. This resource is free AND anonymous which makes it very appealing for many people. Seeing a doctor, called a psychiatrist, or nurse practitioner who specializes in in treatment of addiction, can make medication recommendations and provide prescription medication management.  

In my experience, it is best to avoid combining alcohol and caffeine. These substances have potential lethal consequences and it is not easy to use controlled drinking especially when you have very few physical reminders of when to stop. If you consume more than one drink in one hour, your thinking and motor function are impaired. This puts you at greater risk of consuming drinks faster than you normally would and more of them in a given period, along with spending longer amounts of time drinking. The more you engage in this type of drinking, the more at risk you are for developing health issues and dependence. 

"First you take a drink, then the drink takes a drink, then the drink takes you."


F. Scott Fitzgerald, The Great Gatsby