How Much Alcohol Is Actually Safe?

What to remember

• UK Chief Medical Officers advise no more than 14 units a week for both men and women.
• Spread it over three or more days; saving it up is specifically advised against.
• The old J-shaped curve suggesting light drinking protects the heart is now largely attributed to study design.
• For cancer risk, no threshold below which alcohol is known to be safe has been identified.

The guideline, and what changed

UK guidance was revised in 2016 to a single limit of 14 units a week for men and women, down from the previous higher male figure. The accompanying change mattered more than the number: the guidance dropped the claim that moderate drinking protects health, and stated that the risk of a range of cancers increases with any amount of regular drinking.

Why the red wine finding faded

Early cohort studies repeatedly found light drinkers had lower mortality than abstainers, producing the familiar J-shaped curve. The dominant explanation now is a study design problem: the abstainer group included people who had stopped drinking because they were already ill, so non-drinkers looked unhealthy for reasons unrelated to alcohol. Studies that separate lifelong abstainers from former drinkers, and genetic analyses using Mendelian randomisation, largely flatten the protective portion of the curve.

Counting units properly

A unit is 10ml of pure alcohol. The strength of typical drinks has risen over the decades, so the old shorthand of one drink equals one unit is well out of date. A large 175ml glass of 13 per cent wine is about 2.3 units. A pint of 5 per cent lager is about 2.8. A single 25ml measure of 40 per cent spirit is one unit. Fourteen units is roughly six pints of average-strength beer or six medium glasses of wine across a week.

Spreading and the drink-free days

The guidance is explicit that 14 units should be spread across three or more days, and that saving them for one or two sessions carries its own risks — injury, alcohol poisoning, and the cardiovascular effects of binge patterns, including atrial fibrillation. Drink-free days help by breaking the habit loop, and by giving a realistic measure of how much a drink has become automatic rather than chosen.

The numbers, in one place

Do

• Count units using strength and volume, not number of glasses
• Spread drinking across the week and keep drink-free days
• Use smaller glasses and lower-strength options where you can
• Tell your GP honestly how much you drink; the advice depends on it

Do not

• Do not save units for the weekend
• Do not assume red wine is protective; that finding has not held up
• Do not drink at all if you are pregnant or trying to conceive

When to speak to a doctor

See a GP if you regularly exceed 14 units, find it hard to stop once you start, need a drink in the morning, or feel anxious or shaky without one. Do not stop suddenly without medical advice if you are physically dependent — alcohol withdrawal can cause seizures and can be dangerous. Seek urgent help for vomiting blood, black tarry stools, yellowing of the skin or eyes, or confusion. Drinkline is 0300 123 1110.

Where to go next

• Blood Pressure Numbers, Explained Plainly
• Cutting Salt Without Losing Flavour
• Cholesterol: What the Numbers Mean

Where this comes from

• UK Chief Medical Officers - Low Risk Drinking Guidelines
• NHS - Alcohol units
• World Health Organization - alcohol and cancer risk statement

Medical disclaimer

This article is general information, not medical advice. It cannot account for your own history, medication or circumstances. Always speak to a GP, pharmacist or another qualified health professional before making changes that affect your treatment, and never delay seeking medical advice because of something you have read here. In an emergency, call 999.