The new science of alcohol

madman · Jan 30, 2026

A moderate drinker takes a sobering look at everyone’s favourite social lubricant, asking the question: is any amount safe? In 2023, the Canadian Centre on Substance Use and Addiction pointed to the risk of consuming more than two standard drinks per week.

In Proof: The New Science of Alcohol, The Nature of Things host Anthony Morgan speaks to researchers around the world to learn more about the risks of moderate drinking.

madman · Jan 30, 2026

In this video, Jonathan from the Institute of Human Anatomy explores the physiological reality of alcohol consumption, breaking down how ethanol interacts with your internal organs from the first sip to the morning after. Using cadaver dissections, we examine the stomach lining, the hepatic portal system of the liver, and the delicate structures of the brain to show exactly why new health guidelines are shifting. Whether you are curious about "Dry January" or want to understand the long-term impact on your DNA and cancer risk, we provide the anatomical proof you need to make informed decisions about your health.

Table of Contents

0:00 - Intro
1:07 - Ethanol Absorption: Stomach vs. Small Intestine
2:36 - The Liver’s Detox Process: Enzymes & Toxic Byproducts
5:50 - Alcohol in the Brain: Frontal Cortex & Cerebellum Disruption
7:03 - Why Alcohol Makes You Pee: Pituitary Gland & ADH Suppression
7:36 - Overdose & The Medulla Oblongata: Vital Life Risks
8:23 - Systemic Damage: Heart, Pancreas & Stomach Ulcers
11:00 - Advanced Metabolism: Free Radicals & Liver Cirrhosis
13:51 - What Happens When You Quit? One Month vs. Forever
15:55 - New 2026 Guidelines: Is There a Safe Amount?

Common Questions

What happens to your body during Dry January?

Research shows that even one month alcohol-free can improve sleep, normalize liver enzymes, and lead to moderate weight loss.

How does alcohol reach the brain so fast?

Alcohol freely crosses the blood-brain barrier, where it suppresses regions like the prefrontal cortex (judgment) and the cerebellum (balance).

Why is acetaldehyde so dangerous?

Acetaldehyde is a byproduct of alcohol metabolism that is significantly more toxic than ethanol itself, causing cellular damage and hangovers.

Are the safety guidelines for alcohol changing?

Yes; 2026 dietary updates emphasize that "less is better," as no level of consumption is considered completely safe for optimal health.

Nelson Vergel · Thursday at 5:46 AM

Thread 'Effect of Alcohol on Testosterone'

Oct 3, 2022

Hypogonadism (low testosterone) is common in chronic alcoholic men . Such hypogonadism has been shown to be due to alcohol toxicity occurring at the level of the testes as well as at the level of the hypothalamus and pituitary. Thus, in addition to reduced levels of plasma testosterone and a high prevalence of oligozoospermia. chronic alcoholic men frequently have concomitant “normal” or only minimally increased plasma levels of gonadotropins [follicle stimulating factor (FSH) and luteinizing hormone (LH)]

Studies Found
Low plasma testosterone values in men during...

Nelson Vergel · Thursday at 5:48 AM

Thread 'Habitual alcohol consumption associated with reduced semen quality and hormones'

Oct 9, 2014

BMJ Open 2014;4:e005462 doi:10.1136/bmjopen-2014-005462
Reproductive medicine Research

Habitual alcohol consumption associated with reduced semen quality and changes in reproductive hormones; a cross-sectional study among 1221 young Danish men

Authors

Abstract

Objective Study associations between three measures of alcohol consumption (recent, typical/habitual, binging), semen quality and serum reproductive hormones.

Design Cross-sectional population based study.

Setting...

Nelson Vergel · Thursday at 5:48 AM

On the other hand…

Thread 'Moderate alcohol intake did not affect sperm quality and increased testosterone in men'

Jun 7, 2014

The testosterone increase was most probably due to a slow down of liver metabolism of testosterone caused by alcohol.

Hum Reprod. 2014 Jun 3. pii: deu118. [Epub ahead of print]

Alcohol and male reproductive health: a cross-sectional study of 8344 healthy men from Europe and the USA.

Jensen TK et al

Abstract

STUDY QUESTION:

Is there an association between alcohol intake and semen quality and serum reproductive hormones among healthy men from the USA and Europe?

SUMMARY ANSWER:

Moderate alcohol intake is not adversely associated with...

Guided_by_Voices · Thursday at 12:48 PM

While I would never suggest that someone start drinking and I've seen the damage that comes from people having a bad relationship with alcohol (or other addictions), the recent anti-alcohol push seems deceptive on several fronts.

First, most of the articles say "as little as 1-2 drinks per day can be harmful" however 1-2 drinks per day (7-14 per week) is far from light drinking. AFAIK the observational studies do not look at truly light drinking such as 2-3 drinks per week.

Second, social engagement is one of the most overwhelmingly positive things for health there is, and if someone bundles light drinking with social engagement (going down the local bar and grill twice a week or so) then the positive effects of social engagement may outweigh any negative effects of a small amount of alcohol.

Next, a drink with a meal seems to blunt the rise in blood sugar which is a huge benefit and could well explain the light drinking that seems to go with longevity in many cases.

And last, for many people a glass of wine for example is part of a wind-down de-stressing routine, and de-stressing in itself is health-promoting.

So, there is much more to the story that just the chemical pathways.