The enzymes alcohol dehydrogenase (ADH), cytochrome P450 2E1 (CYP2E1), and catalase all contribute to oxidative metabolism of alcohol. ADH, present in the fluid of the cell (i.e., cytosol), converts alcohol (i.e., ethanol) to acetaldehyde. This reaction involves an intermediate carrier of electrons, +nicotinamide adenine dinucleotide (NAD), which is reduced by two electrons to form NADH. Catalase, located in cell bodies called peroxisomes, requires hydrogen peroxide (H2O2) to oxidize alcohol. CYP2E1, present predominantly in the cell’s microsomes, assumes an important role in metabolizing ethanol to acetaldehyde at elevated ethanol concentrations. Acetaldehyde is metabolized mainly by aldehyde dehydrogenase 2 (ALDH2) in the mitochondria to form acetate and NADH.

While those who have developed tolerance may not feel the effects of alcohol as readily, they are still doing damage to their liver and may begin a pattern of dependency. Abstaining from drinking will gradually lower the body’s ethanol resistance. As a result of the resistance decrease, the person will be able to feel the effects of booze after drinking less than before. This is an effective way of reducing alcohol tolerance and the prevention of the development of alcohol abuse habits and alcohol dependence. Variations in the genes encoding ADH and ALDH produce alcohol-and acetaldehyde-metabolizing enzymes that vary in activity.

Products of Oxidative Metabolism of Alcohol

Alcohol withdrawal symptoms develop if someone who is dependent on alcohol (i.e. has alcohol dependence) stops drinking very suddenly, or goes too long without alcohol. Some research studies have suggested that ethnicity can affect alcohol tolerance. For example, people of certain racial and ethnic backgrounds, particularly people who are East Asian, have a higher prevalence of alcohol sensitivity, due to genetic factors. Certain health-related factors, such as your physical activity level and other co-occurring health problems, can affect your tolerance to alcohol.

Alcohol dose-dependently produced hypothermia in mice, an effect that decreased, regardless of dose, when the mice were tested with the same doses on day 2. John C. Umhau, MD, MPH, CPE is board-certified in addiction medicine and preventative medicine. For over 20 years Dr. Umhau was a senior clinical investigator at the National Institute on Alcohol Abuse and Alcoholism of the National Institutes of Health (NIH). We are here to provide assistance in locating an Ark Behavioral Health treatment center that may meet your treatment needs. We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. All Addiction Resource content is medically reviewed or fact checked to ensure as much factual accuracy as possible.

How to Improve Your Alcohol Tolerance

Reverse alcohol tolerance is a critical state for the liver and can lead to other health complications. For people of various ethnicities, how to build alcohol tolerance genetic differences mean differences in AT levels. The majority of Asians don’t have ADH and thus cannot metabolize alcohol.

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This happens because the ADH levels, which is the enzyme that initially metabolizes the alcohol dehydrogenase into acetaldehyde, are different for every individual. The acetaldehyde is a toxic intermediate product that is later transformed into water and carbon dioxide. ADH is our best defense against the extremely toxic effects non-metabolized ethanol produces on our cardiac and nervous systems. People who use slower variants of this enzyme are more likely to develop a resilience to booze and a dependence.


Have you ever known someone who could consume large amounts of alcohol and not display any obvious signs of intoxication? That is because that person has developed a functional tolerance to alcohol. You are more likely to develop a high tolerance to alcohol if you drink very often and in heavy amounts. Children of alcoholics have a high risk of developing tolerance because of exposure to alcohol from a young age. Several studies have shown that sons of alcoholics were less impaired during drinking bouts compared to sons of non-alcoholics. It develops over time, meaning that a dedicated drinker may need consistently higher volumes of alcohol to achieve the same physical effects over the weeks and months of drinking.

Alcohol is the most frequently consumed type of drink other than the carbonated soft beverages. Unfortunately, alcohol is an intoxicating beverage which produces effects that vary from excitement to narcosis, depending on the individual tolerance and the amount consumed. This type of alcohol is included in different fermented and distilled beverages in varying percentages. What’s the best way to increase my tolerance between now and the end of September?

The first month is the hardest, but gradually decreasing the number of drinks per week can help bring down the tolerance level without suffering from withdrawals. Genetic differences do account for some differences in alcohol tolerance, which in some cases fall along ethnic lines. As described above, most Asians don’t have the alcohol metabolic enzyme alcohol dehydrogenase (ADH), which means they tend to get drunk faster than Americans or Europeans.

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