Even in the hard-drinking intellectual circles of Paris, French philosopher and feminist icon Simone de Beauvoir discovered that a glass of wine had more of an effect than expected. De Beauvoir once joked that two glasses of water made her feel dizzy, long before any existential debate began.
Decades later, science could explain it: Women’s bodies process alcohol differently than men’s – often faster and more intensely – and women’s brains also respond more strongly to its beneficial effects, even if they drink the same amount of alcohol as men.
How does alcohol move through the body?
Alcohol affects the body almost immediately. Before it reaches the stomach, the taste buds signal the brain, causing small changes in heart rate, blood flow and brain chemistry to prepare the body.
When you swallow alcohol, a small amount is absorbed in the stomach, but most passes into the small intestine, where it rapidly enters the bloodstream.
Some of it is broken down in the stomach and liver by an enzyme called alcohol dehydrogenase (ADH), a process known as first-pass metabolism (FPM).
In 1990, researchers gave equal amounts of alcohol to 20 men and 23 women—adjusted according to each person’s body weight. Women drank the same amount of alcohol as men – but their bodies initially filtered less alcohol, so more of it entered the bloodstream, resulting in higher blood alcohol levels on average.
But intoxication is not just a matter of how fast alcohol enters the bloodstream. What happens next – in the brain – also varies by biological sex.
Debate on gender differences and body weight
Scientists largely agree that women, on average, feel the effects of alcohol sooner. Where they disagree is on why this is so.
Rainer Spannagel, a German neuropharmacologist and addiction researcher, cites body weight as a key factor. “It’s not the enzymes, it’s the body weight,” he told DW.
Ethanol also distributes throughout so-called parts of the body – including the brain and organs, Spangel explained.
Smaller bodies mean smaller compartments. “If a man drinks half a bottle of wine, and a woman drinks the same amount of wine, the same amount of ethanol accumulates in a smaller body.”
But other researchers argue that weight alone doesn’t explain everything about alcohol’s effects on women.
Beyond size: enzymes, body structure, and the brain
Alcohol starts working as soon as it is consumed and even after affecting the brain, it continues to have a good effect on the body.
“Maybe it’s not so much body weight or size, but the big sex-difference difference in structure,” said Edward Scotts of Louisiana State University, who studies the neurobiological mechanisms of alcohol use disorder.
Women generally have more body fat and less water than men, so alcohol becomes more concentrated in their blood.
“This is in addition to the ADH difference,” Scotts said. ADH, he said, was an important early filter.
“As soon as you drink alcohol, it goes to your stomach first, and you have some ADH in your stomach — but men have more than women,” he said. “Therefore, men are able to metabolize it much faster in the early stages.”
This intrinsic difference helps explain why health guidelines define binge drinking or hazardous drinking differently for men and women.
Jill Baker, a researcher at the University of Michigan who specializes in gender-based differences in the brain and behavior, said metabolism and absorption shape addiction but that the process rarely occurs with daily drinking.
“A glass of wine is the same size whether it’s a man or a woman [drinking it]”I don’t ask him how much he weighs and I underweight him,” Baker said.
As a result, women often receive higher doses than their bodies can handle before the enzymes begin to function.
Alcohol addiction in women or how alcoholism affects the brain’s reward systems
Once alcohol reaches the brain, women see a phenomenon called telescoping: the progression from alcohol abuse to dependence is much faster. “They become addicted more quickly and consume larger amounts in less time,” Baker said.
Baker’s observation is supported by research showing that women progress more quickly than men toward serious alcohol-related problems and entry into treatment for the first time, often after fewer years of drinking and less lifetime consumption.
Clinical studies conducted in the 1980s, 1990s, and 2000s consistently found that women experienced shorter intervals between major drinking episodes, despite they generally beginning regular use later in life than men.
Hormones also play a role. Estradiol, the primary hormone produced by the ovaries, increases dopamine release in the brain.
Alcohol indirectly increases dopamine and estradiol enhances its effects.
“During ovulation, women crave substances more, making them more likely to drink more alcohol,” Baker said.
And stress also matters. Women are more likely than men to use alcohol to self-treat anxiety or depression.
“Sure, some men will self-medicate,” Baker said, “but a larger percentage of women are turning to alcohol and drugs to self-medicate.”
Rethinking equality at the bar
For Baker, science has social implications. “I’m a woman of the second wave of feminism of the 1970s,” she said. “There was a strong belief [then] That we have the right to drink alcohol like men.”
That belief was rooted in equality – but biology can complicate equality.
“Women need to be aware that if they drink with the man standing next to them, not only will they get drunk more quickly, but the long-term consequences may also be more devastating,” Baker said.
The conclusion is not about restrictions, but about understanding. Alcohol does not cause much harm because women are weak drinkers. It is more intense because women’s bodies, enzymes, hormones and brains react differently, long before tolerance comes into play.
Edited by: Zulfikar Abbani