No Amount of Alcohol Is Safe for Your Brain, New Landmark Study Finds

There’s a long-standing idea that drinking a little booze might be good for you. However, powerful research published in BMJ Evidence-Based Medicine challenges this notion, especially when it comes to brain function, finding that any level of alcohol exposure actually raises your risk of dementia.

The 2025 study, led by the University of Oxford, Yale University, and the University of Cambridge, analyzed data from more than half a million adults aged 56 to 72 who participated in two long-term research studies through the United States’ Million Veteran Program and the United Kingdom’s Biobank. Throughout the study, participants answered questions about their alcohol consumption until they received a dementia diagnosis, had a follow-up visit without a dementia diagnosis, or died. 

Of the participants, 90% reported they drank some level of alcohol, and more than 14,500 individuals were diagnosed with dementia. Researchers then used genetic analysis to examine how likely people were to drink alcohol in the first place, where they discovered that those who consumed even light amounts of alcohol (roughly one to three drinks a week) had a 15% higher risk of developing dementia. 

The findings strongly concluded that any amount of alcohol increases dementia risk, but the more alcohol someone drinks, the higher their risk becomes, says Randall Turner, DO, a physician double board-certified in psychiatry and addiction medicine and the medical director of Able To Change Recovery. However, one nuance to consider is that non-drinkers tended to have lower socioeconomic status and education levels, both of which are associated with poorer pre-morbid cognitive function and increased vulnerability to dementia, Turner adds. 

More than 6 million Americans are affected by dementia, so to better understand the role alcohol plays in its diagnosis, we asked experts to weigh in. 

How does alcohol raise the risk of dementia?

At a high level, alcohol promotes inflammation, oxidative stress (an imbalance of free radicals and antioxidants that can lead to cell damage), and the accumulation of toxic proteins (namely, beta-amyloid), which are all implicated in dementia and other brain conditions, Turner says. Chronic alcohol use also causes direct neurotoxicity (the harmful effects of substances on the nervous system), damaging brain cells and accelerating neuronal death, he says. 

Furthermore, Turner explains that alcohol disrupts acetylcholine and glutamate neurotransmitter systems in the body, which are critical for memory and learning. Over time, this disruption can then lead to brain atrophy, especially in regions essential for cognition like the hippocampus and frontal lobes, he notes.

There’s also the issue of sleep, says Anoopinder Singh, MD, a board-certified psychiatrist with Mindpath Health. Because alcohol reduces rapid eye movement (REM) sleep, which is essential for memory consolidation and emotional regulation, heavy drinking is known to impair cognitive function and mood, he explains.

In the short term, this is why you may feel foggy and agitated after a night of drinking, but over the long term, this alcohol-induced daze can lead to memory loss, slow processing speed, and poor problem-solving skills.

Last but not least, alcohol contributes to vascular damage, which raises the likelihood of strokes and small vessel disease, resulting in increased dementia risk, according to Turner.

So how does alcohol cause so much damage, you ask? “The primary culprit is ethanol and its metabolite acetaldehyde,” Singh says. “Ethanol alters neuronal signaling and sleep, while acetaldehyde drives oxidative stress and neuroinflammation.” Alcohol also generates free radicals in the body, triggering neuroinflammation and interfering with nutrient absorption, ultimately contributing to brain cell death and increased dementia risk.

Is the risk of alcohol-related dementia different between men and women?

The risk of alcohol-related dementia is real for both men and women. That said, women are typically more vulnerable to the harmful effects of alcohol on the brain than men, even when they consume it in lower amounts and for shorter durations, Turner says. 

“This is due to metabolism and body composition in which women typically have less body water and lower levels of alcohol-metabolizing enzymes than men, so alcohol concentrations in the blood and brain are higher for women after drinking the same amount [as] their male counterparts,” Turner explains.

Estrogen (a female sex hormone) also interacts with alcohol in ways that increase brain vulnerability, and studies have shown that women develop alcohol-related brain shrinkage and cognitive decline more quickly than men, Turner says. On top of that, women with alcohol misuse are more prone to conditions that compound dementia risk, such as depression, nutritional deficiencies, and liver disease.

That being said, men typically drink more and binge more, so harm is substantial in both genders, Singh says. “The risk is real for everyone, and gender differences don’t create a ‘safe’ level of alcohol consumption.”

What are the other known health risks of alcohol?

Alcohol is a psychoactive substance with well-documented risks that affect multiple systems in the body. In addition to dementia, here are some of the most significant health risks to consider before having another drink. 

Increases the risk of liver disease and stomach cancer 

Excessive alcohol consumption overwhelms the liver’s ability to detoxify the body, potentially leading to adverse health outcomes like fatty liver disease, hepatitis, and chronic liver disease, Turner says. Alcohol is also a known carcinogen, so chronic use raises the risk of cancers of the mouth, throat, liver, breast, colon, and esophagus, he adds. 

Decreases brain activity 

On top of raising the risk of dementia, alcohol decreases brain activity by depressing the central nervous system, Singh says. As a result, research proves that booze can lead to changes in mood, awareness, feelings, behavior, and cognitive function when regularly consumed in excess.  

Disrupts the gut microbiome 

Alcohol damages the intestinal lining and increases gut permeability, which allows toxins and harmful pathogens to enter the bloodstream more easily. Some gut permeability is necessary for optimal nutrient absorption, but excessive permeability can trigger inflammation, digestive issues, and even chronic diseases like inflammatory bowel disease and irritable bowel syndrome.

Weakens cardiovascular health 

Chronic alcohol use increases the risk of heart disease, since heavy drinking raises blood pressure, promotes irregular heart rhythms, weakens the heart muscle, and increases stroke risk, Turner says. In fact, research found that women who reported a high alcohol intake had a 45% higher risk of heart disease than those reporting a low intake. Men with a high overall alcohol intake were 33% more likely to develop heart disease compared to those with a moderate intake.

However, it’s important to note that some studies suggest light to moderate alcohol consumption may have a neutral or even slightly protective effect on heart health, particularly for certain populations.

How much alcohol is too much?

The official U.S. guidelines advise up to one drink a day for women and up to two drinks a day for men, but it’s heavily stressed that less is better. To put this into perspective, one standard drink is five ounces of wine, 12 ounces of beer, or an ounce and a half of spirits.

With that in mind, the frequency with which alcohol can or should be consumed is nuanced, since the World Health Organization recently announced that no amount of alcohol is beneficial or safe for your health. The National Academies of Sciences, Engineering, and Medicine, on the other hand, found lower mortality rates for moderate drinkers as compared to those who never drink, though more research is needed. 

“If people choose to drink, keeping intake as low and infrequent as possible likely minimizes risk, but this new study suggests dementia risk may rise even below those limits, reinforcing ‘the less, the better’ messaging,” Singh says. “From a brain-health standpoint, this study indicates no proven safe threshold for alcohol consumption.”