What determines your alcohol tolerance?



I mean, I know weight and height are a thing, but what variables make metabolizing alcohol more or less effective? Why does a person get drunk with a beer while a similar one in weight and height can drink no problem?

In: Biology

Experience, stomach contents, consumption rate, and body composition.

Experience – The more you drink (and the more frequently) the “higher” tolerance your body will have. Basically it starts to adapt to increasing levels of alcohol.

Stomach contents – If you have food in your stomach that is able to absorb some of the alcohol, it will slow how fast the alcohol is entering your system. Say you eat a chunk of dry bread. It will get wet with saliva from your mouth, but nowhere near saturated. So once it enters your stomach it will absorb some of the liquid there. This means your body has to break down that bread for the alcohol to come out. This won’t keep you from getting as drunk, it just slows down the rate you get there some. It definitely won’t sober you up. It doesn’t remove any of the alcohol in your blood, it just slightly slows the rate new alcohol enters.

Consumption rate – literally how much alcohol you are consuming in a given time frame. Beer is usually 4-8% ABV. Lots of liquors are 40% ABV. So if you take 3 ounce and a half shots, you may have consumed less liquid volume than a single beer, but you consumed a hell of a lot more alcohol, and you did it very quickly.

Body composition – Alcohol is more soluble in water than fat. Muscle contains more water than fat does. So a person with more muscle (even if similar height and weight) will tolerate alcohol better.

Not a scientific article, but a decent break down:


Doctor here, and back when I was working the ER of a notoriously hard partying college town Thursday through Sunday was prime time for alcohol related overdoses.

The short answer here is that there are far too many variables to list. Body mass, experience, liver function and method of delivery are the big ones but all the rest like hereditary, medications, certain comorbidities, etc can also add up to tip the scale as well. This is generally true for any intoxicant even tightly regulated/titratable pharmaceuticals administered by a healthcare professional.

In addition to the great answers so far, people have different amounts of the enzymes which break down alcohol. In general, women have less than men (of equal size & body composition). I believe there are also some differences based on country of origin, but I don’t remember which groups are high or low.