We all know alcohol makes you drunk if you have enough of it, but do you know why? Or how? Let’s get into the science behind intoxication.

Meet Ethanol

Ethanol — also referred to as alcohol, ethyl alcohol, or grain alcohol — is the primary ingredient in alcoholic bevvies. It’s also the one that causes drunkenness. Ethanol is a clear, colorless liquid that’s a byproduct of plant fermentation. This means it’s not produced on its own, but as a result of another process.

Alcohol is mainly a depressant, but it actually has stimulating effects when you first start drinking. It begins to do its thing pretty much the moment it goes into your mouth, and its effects become more noticeable as the alcohol makes its way through your body. Here’s a closer look at that journey. As soon as alcohol passes your lips, some of it gets into your bloodstream through the tiny blood vessels in your mouth and on your tongue.

Then it makes its way down your throat and into your stomach. Up to 20 percent of the alcohol you drink goes into your bloodstream through your stomach. The rest of it gets in your bloodstream via your small intestine. If you have food in your stomach, the alcohol will stick around longer. Without food, though, it moves to your bloodstream a lot faster. The more alcohol in your blood at one time, the drunker you’ll feel.

Alcohol on the Brain

Alcohol can hit you pretty fast. It typically reaches your brain within 5 minutes, and you can begin feeling the effects within 10 minutes. When the concentration of alcohol begins to increase in your bloodstream, you’ll start to feel good. This is because your body is releasing the “feel good” hormone dopamine. You might feel happy, more social and confident, and less inhibited.

As you get drunker, you’ll start to experience more physical symptoms. This happens because alcohol depresses your central nervous system and interferes with your brain’s communication pathways, which affects how your brain processes information. This causes symptoms like:

  • slurred speech
  • loss of coordination
  • blurred vision
  • dizziness

Your brain produces antidiuretic hormone (ADH), which tells your kidneys how much water to conserve. Alcohol limits ADH production, which brings us to our next body part— the kidneys. When alcohol suppresses ADH, it causes your kidneys to release more water, which is why you pee more when you drink. This is where the idea of “breaking the seal” — which, BTW, isn’t actually true — comes from. Peeing a lot and not getting enough nonalcoholic fluids can lead to dehydration and make you even more drunk.

Blood Alcohol Content (BAC)

Your liver can only oxidize one unit of alcohol per hour. So, the more you drink over a shorter period of time, the more alcohol hangs around in your bloodstream. The result is a higher blood alcohol content (BAC) and a higher risk of alcohol poisoning. Your BAC definitely plays a role in drunkenness, but it doesn’t entirely jive with how drunk you feel. A lot of other things can affect that. Some of the other factors to consider are:

  • Your weight. The less body tissue you have to absorb alcohol, the more — and faster — you’ll feel its effects. A bigger body gives the alcohol more space to diffuse.
  • Your biological sex. Differences in body composition are why males and females metabolize alcohol at different rates. Females typically have more body fat, which holds on to alcohol longer. They also have less body water to dilute alcohol and fewer of the enzymes that metabolize it.
  • Your age. As you age, your metabolism slows, your body fat percentage increases, and your body water decreases. This can all impact how your body processes alcohol and how it affects you.
  • The type of alcohol. Alcohol content varies between drinks. Highly concentrated beverages, like vodka and gin, are absorbed faster by your body. It also absorbs fizzy and bubbly drinks, like champagne or soda mixes, quicker than other drinks.
  • How fast you drink. Chugging rather than sipping will increase your BAC faster and cause you to feel drunker.
  • How much food is in your stomach. Food in your stomach slows the absorption of alcohol. If you drink on an empty stomach, the alcohol is absorbed more rapidly, causing you to feel it faster and harder.
  • Any medication you’re taking. Certain medications can affect absorption of alcohol or interact with it and intensify its effects.
  • Your overall health. Certain health conditions, like those that affect liver and kidney function, can impact how your body processes and eliminates alcohol.

The Takeaway

As you drink, alcohol enters your blood through your mouth, gut, and stomach, and even your lungs. Your brain releases feel-good hormones and your kidneys generate a lot of pee. Your liver responds by breaking the alcohol down into water and carbon dioxide.

However, those feel-good vibes can quickly turn to confusion, slurred speech, and risky decisions. And regularly getting on them can lead to long-term and potentially fatal complications in your liver, heart, and stomach. It’s fine to get merry every so often aka mindful drinking, but it’s important you keep an eye on your consumption as moderation can turn into a maladaptive habit quicker than one would think.