How Long Does Alcohol Stay In Your Body, According To Science?

Most adults have experienced a hangover before, some worse than others, after imbibing in a few too many drinks the night before. Headaches, nausea, exhaustion, and thirst are all symptoms of overindulging in cocktails, brews, and the like that can last hours or even an entire day. There are many factors behind alcohol causing a hangover, but none of those reasons affect how long the alcohol itself stays in your system. While you might assume that its presence in your body would be gone by the morning, alcohol actually remains (and is detectable) for much longer than most people might think. 

The exact length of time that alcohol stays in your system is dependent on a lot of factors, like age, sex, genetics, your overall physical health, and the kind of alcoholic beverage consumed. You're likely aware that alcohol can affect you more quickly when you drink on an empty stomach, but imbibing on a full stomach doesn't negate its effects, nor the eventual rise in blood alcohol concentration (BAC). While the amount will vary per individual, generally, alcohol can be detected in your body up to anywhere from 6 to 72 hours later, according to American Addiction Centers. Saliva and blood tests can detect alcohol up to 12 hours after drinking, with breath and urine tests detecting amounts anywhere between 12 to 24 hours, or even up to 72 hours later with extremely heavy drinking. Shockingly, alcohol use can even be detected in hair for almost 90 days after imbibing. 

Even though alcohol passes through the stomach like any food or liquid does, it doesn't get digested in the same way that most other things that humans consume do. When alcohol reaches your upper digestive tract, much of it actually goes into your bloodstream. From there, it travels throughout your body via your blood and then makes its way to your brain, where you begin to feel the alcohol's effects.

The body metabolizes, or breaks down, some alcohol through enzymes in the stomach; although not every person has these alcohol-digesting enzymes in their gut. However, the liver plays the largest role in filtering alcohol through the body, converting it into a byproduct that can be eliminated through additional enzymatic processes. 

While common lore advises that drinking coffee or water, or even eating food, will aid in quickly sobering up a person, those things don't actually have much of an effect on the alcohol in your bloodstream or how it affects you. Similar beliefs that drinking liquor before beer will have fewer consequences than drinking beer before liquor are also invalid, as the types of alcohol you drink will all eventually enter your bloodstream and remain there for about the same amount of time.