Absorption Rate Factors

Does alcohol affect people differently?

Your level of intoxication varies according to an individual's physiological and biological factors. Drinking the same amount as your friends and/or family will affect you in different ways. The following are some factors that may affect the absorption of alcohol.


Males have a higher concentration of an enzyme that allows them to break down alcohol more effectively than a woman. Also, alcohol is water-soluble and women tend to have a higher percentage of body fat, which does not absorb alcohol and thus results in a higher blood alcohol concentration. An additional factor is hormone differences. Research suggests that the menstrual cycle and the use of any medication containing estrogen may influence the liver's ability to metabolize alcohol.

Body Weight A larger person has more blood and water in their body and will have a lower blood alcohol concentration (BAC) than the smaller individual.
Full vs. Empty Stomach When food is ingested, the pyloric valve at the bottom of the stomach will close in order to hold food in the stomach for digestion and thus keep the alcohol from reaching the small intestine. The larger the meal and closer in time to drinking, the lower the peak of alcohol concentration.
High Stress vs. Relaxed

Because alcohol is a depressant, alcohol will have a greater effect on you when you’re depressed or under a lot of stress. High Stress vs. Relaxed Alcohol is absorbed more quickly from the small intestine than it is from the stomach. Stress causes the stomach to empty directly into the small intestine, where alcohol is absorbed even faster. Decreased stress has been shown to slow the rate of gastric emptying which in turn delays the absorption of alcohol, and peak blood alcohol concentrations are reduced. (Holt, 1981)

Carbonation Liquor mixed with soda or other bubbly drinks speeds up the passage of alcohol from the stomach to the small intestine, which increases the speed of absorption.

Other drugs and medications often have adverse effects and unpredictable interactions with alcohol. Know the potential interactions with medications/drugs you may be taking and whether or not alcohol use has possible side effects. Because alcohol is a depressant, any depressant drug will increase the effects of alcohol by as much as 10 times. In addition, many other drugs can interact with alcohol in unpredictable ways.

For example, aspirin, when mixed with alcohol, may cause damage to the stomach lining, decreasing blood clotting and resulting in internal bleeding. In addition, acetominophen (i.e., Tylenol) can cause liver damage when mixed with alcohol. Antihistamines can make you drowsy and the depressant effects of alcohol will amplify that feeling. You can ask a doctor or pharmacist if it is safe to drink alcohol while taking a medication or over-the-counter drug. Find out more about harmful interactions from the National Institute on Alcohol Abuse and Alcoholism.

Health Concerns

Health Concerns Your body may be predisposed to handling alcohol poorly. Genetic enzyme deficiencies (alcohol dehydrogenase and aldehyde dehydrogenase), diabetes, hypertension, depression, seizure disorder, and other health conditions may decrease your body's ability to process alcohol and therefore present increased health risks. Alcohol use may exacerbate these conditions and/or increase your risk of developing chronic diseases.

Illness causes dehydration. Dehydration has a number of effects that cause greater intoxication. First, you have less water in your body, so the alcohol has less area to be absorbed in the body, resulting in greater intoxication. Dehydration also negatively impacts the liver’s efficiency at eliminating alcohol.

Chugging vs. Sipping Going overboard when drinking is like overdosing. Your body may respond by shutting down. First, your cognitive system shuts down and you lose your inhibitions. Pour in more alcohol, and your body might force you to vomit (first sign of alcohol overdose), or pass out (other brain functions shut down). Finally, your sympathetic and parasympathetic systems will shut down due to a systemic alcohol overdose. Enjoy your drink more slowly and spread out your drinking over time. You can more effectively monitor your level of intoxication.

Fatigue causes many of the same symptoms that are caused by alcohol intoxication. These and other symptoms will be amplified if alcohol intoxication is concurrent with fatigue.

When you’re tired, your liver is less efficient at eliminating alcohol due to the low energy level. Therefore, drinking the same amount of alcohol when you’re tired will result in a higher BAC than when you’re rested.

Elimination Factors

The liver is responsible for the elimination of alcohol. The liver eliminates of 95% of ingested alcohol from the body through metabolism. A person will eliminate one standard drink of 80-Proof alcohol (1.5 oz) of alcohol per hour. Several factors influence this rate.  Because the body metabolizes alcohol at a fairly constant rate, consumption at a rate of one drink per hour will, for most people, maintain current BAC.


Tolerance is different from BAC in that tolerance is the physical and mental acclimation to alcohol, developed after habitual use. Tolerance does not give you immunity to poor judgment, improve your motor skills, or quicken your reaction time. Acclimating to being drunk gives a false sense of safety since your body still processes alcohol and BAC can still rise, leading to many of the same negative effects of over drinking such as alcohol overdose.

There are several types of tolerance produced by different mechanisms:

  • Genetic Tolerance. Some aspects of tolerance are genetically determined and affect drinking behavior (less than 5% of tolerance effects).
  • Metabolic Tolerance. An increase in enzyme activation in the liver increases the elimination rate of alcohol from the body (10% - 15% of tolerance effects).
  • Functional Tolerance. Brain functions adapt to compensate for the disruption caused by alcohol in both their behavior and bodily functions. The concentration of different neurotransmitters change in the brain. These effects also intensify handovers and produce cravings for alcohol related to addiction  (30% - 35% of tolerance effects).
  • Environmental Tolerance. Over different drinking sessions, the cues associated with intoxication (people, places, smells, tastes) become associated with intoxication and reduces feelings of intoxication in similar situations where the same cues are present. Thus, in situations with different cues, we feel more intoxicated (50% – 55% of tolerance effects ).
Gender Differences

Another gender-based difference is in the elimination of alcohol. Although not explained, studies indicate that women eliminate alcohol from their bodies at a rate 10% greater than that of men.

It is important to remember that this difference in the eliminate rate is by far outweighed by gender differences related to distribution factors. Thus, women will, in most cases, reach higher BACs than male counterparts that consume the same amount of alcohol.