What alcohol really does to your body (from the very first drink)

Ce que l’alcool fait vraiment à votre corps (dès le premier verre) - ONSKYN

Dry January: what alcohol really does to your body (from the very first drink)

The holidays are over, January is coming, and with it Dry January .
After a few weeks of heavy drinking, many people ask themselves the same question: does taking a break from alcohol really change anything?

For years, the messages surrounding alcohol have been vague and contradictory.
A glass of red wine is said to be “good for the heart.” There’s talk of moderate consumption without ever clearly defining it. The refrain is always, “It’s all about the dose.”

What is much less explained are the precise biological mechanisms that are triggered from the very first drink. Why even so-called moderate consumption has measurable effects on the brain, sleep, gut, and hormones .

At ONSKYN, we don't talk about guilt.
We're talking about understanding what's really happening in the body , so that we can make conscious choices.

What really happens when you drink alcohol?

A standard drink contains approximately 10g of pure alcohol :

  • 25 cl of beer

  • 10 cl of wine

  • 3 cl of spirits

The alcohol you are consuming is ethanol .
Unlike carbohydrates, fats, or proteins, the body cannot store or use it . It must eliminate it immediately.

👉 Result:
Alcohol metabolism takes priority over all other functions:

  • digestion

  • cellular repair

  • hormonal regulation

  • energy production

Everything else becomes secondary.

Alcohol metabolism: the channel that explains everything

Ethanol is transformed according to this sequence:

Ethanol → Acetaldehyde → Acetate

Two enzymes are involved:

  • ADH (alcohol dehydrogenase) : ethanol → acetaldehyde

  • ALDH (aldehyde dehydrogenase) : acetaldehyde → acetate

The key point to understand

👉 Ethanol is not the main problem.
👉 It's acetaldehyde.

Acetaldehyde is:

  • highly responsive

  • classified as carcinogenic

  • responsible for oxidative stress, inflammation, and cell damage

In some people (particularly those with genetic variants of ALDH2), this conversion is slower.
The signs are known: facial redness, palpitations, discomfort.
This is not “bad social tolerance” — it is a biological signal of toxic buildup .

Why does alcohol disrupt so many systems at once?

1. Alcohol penetrates everywhere

Alcohol is both:

  • water-soluble (soluble in water)

  • fat-soluble (soluble in fats)

It therefore crosses all cell membranes without difficulty:
brain, intestines, liver, muscles, hormonal tissues.

Within minutes, it spreads throughout the entire body.

2. It disrupts energy metabolism

Each step in alcohol metabolism consumes NAD⁺ , an essential cofactor for cellular reactions.

Result :
The NAD⁺/NADH ratio drops , and the cells lack metabolic fuel.

Direct consequences:

  • Slowed glucose production → nocturnal hypoglycemia

  • fat burning blocked

  • Hepatic fat storage is promoted

👉 Simple translation:
The body puts its normal functions on hold to deal with a toxic molecule in an emergency. In a Regarding longevity, it should be avoided.

The 4 systems most affected by alcohol

1. The brain: neurochemical debt

Alcohol causes a rapid release of dopamine and serotonin .
It's the "relaxation" effect, sociability, mild euphoria.

But this peak is followed by a compensatory collapse .

In the hours and days that follow:

  • hangxiety

  • irritability

  • mental fog

  • decreased motivation

It's not psychological.
It is a measurable neurochemical response .

The data show a dose-response association between alcohol and reduced brain volume, even at so-called moderate levels (7 to 14 drinks per week), particularly in the hippocampus and prefrontal cortex.

👉 Speed ​​matters as much as quantity.
Two drinks in 30 minutes do not have the same impact as two drinks in 2 hours.

2. Sleep: sedation ≠ recovery

Alcohol helps you fall asleep faster.
But it severely degrades sleep quality .

During the night:

  • First half: heavier but not very restorative sleep

  • Second half: frequent micro-awakenings, fragmentation

Alcohol:

  • reduces deep sleep

  • decreases REM sleep

  • increases nighttime awakenings

Result :
8 hours in bed, but incomplete recovery.

Timing is crucial:
A drink at 7pm does not have the same impact as a drink at 10pm.

3. The gut: barrier, inflammation and the brain

Alcohol:

  • alters the microbiota

  • weakens the intestinal barrier

  • increases permeability

Bacterial fragments then pass into the bloodstream, triggering systemic inflammation .

Common consequences:

  • unexplained fatigue

  • mental fog

  • unstable mood

  • sensitive digestion

  • dull or reactive skin

👉 Gut, immunity and brain are closely linked.

4. Hormones: a subtle but real imbalance

Alcohol is disruptive:

The stress axis (HPA)
→ increase in baseline cortisol
→ increased sensitivity to stress
→ Reduced recovery

Hormonal balance
→ increase in aromatase
→ conversion of testosterone to estrogen

These imbalances are observable in both men and women.

In the long term, alcohol is also linked to several cancers, including breast cancer, with no proven “safe” threshold.

Dry January: What can change in 30 days

A month without alcohol often allows us to observe:

  • more stable sleep

  • a more regular energy

  • a decrease in anxiety

  • improved mental clarity

  • a more comfortable digestion

Not by magic.
But because the body can finally focus on its normal functions .

How to succeed at Dry January

  • Identifying automatic behaviors : context matters more than the drink

  • Replacing the ritual : the brain seeks sensory stimulation, not just alcohol.

  • Adjusting the environment : visible and accessible alternatives

  • Clarifying one's "why" : energy, sleep, curiosity, autonomy

  • Observe the changes : sleep, mood, concentration

  • Surrounding oneself with others : shared experience strengthens commitment

In short,

There is no dose of alcohol that has been scientifically proven to be completely without effect.
Even moderate consumption influences the brain, sleep, gut, and hormones.

Dry January is not mandatory.
It's an experience and a preventative approach.

Understanding what alcohol actually does to your body then allows you to make conscious choices.

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