How long alcohol is detectable in the body (in the blood, in the saliva/on the breath, or in urine) depends on several factors.
Generally, a period of drinking lasts for an hour or more, sometimes going on for several hours.
Although alcohol passes through the digestive system, it requires little to no actual digestion. Once consumed, 20 percent of the substance moves directly into the blood vessels and is carried throughout the body and to the brain. The rest enters the bloodstream after being absorbed by the small intestines. This process is slowed when there’s food in the stomach and intestines, causing it to take longer for the individual to become intoxicated.
After alcohol enters the bloodstream, it’s taken to the liver to be metabolized. Despite the fact that people get intoxicated from alcohol at different rates and from different amounts of the substance, a healthy liver metabolizes it at the same rate regardless of sex, race, or weight. However, metabolization in the liver is not the only factor that determines how fast alcohol leaves the body. Other factors include:
On average, the liver can metabolize 1 ounce of alcohol every hour. The average person’s blood alcohol level from a single ounce of alcohol will rise to 0.015, so about every hour, that much alcohol will pass out of a person’s body. The amount of alcohol that will produce a blood alcohol limit of 0.08, the legal limit for driving, will take approximately 5.5. hours to leave the system.
This process is a bit different when someone starts consuming alcohol faster than the liver can metabolize it.
In particular, once the blood alcohol level rises beyond 0.055, blood and body tissues start to absorb the extra alcohol, producing unpleasant effects like depressed mood, irritability, nausea, vomiting, disorientation, and memory loss.
When it comes to urine tests, alcohol generally stays in urine for 12-36 hours, depending on how much was consumed, though some tests can detect the substance for up to 48 hours. The most advanced urine tests can detect a substance produced by the metabolization of alcohol for up to 80 hours after the last drink.
Alcohol can also be detected on the breath for up to 24 hours after the last drink. Like most substances, alcohol can be detected in a person’s hair for around 90 days after the last consumption. It can also be detected via saliva swab, which can find traces of alcohol 10-24 hours later.
Knowing more about how alcohol is metabolized and keeping track of one’s likely blood alcohol levels can help to prevent unintended over-intoxication and accidental death. It can also help to prevent building a tolerance and becoming addicted to alcohol, which puts a person at risk for serious health problems.