Alcohol, Honestly: Dose, Risk, Sleep and Who Should Not Drink

A couple of drinks in the evening feel ordinary and seem to help you fall asleep. The honest answer: the World Health Organization says no level of drinking is safe for health, risk rises with the amount, and alcohol disrupts the second half of the night. For most adults this is about drinking less; for some — in pregnancy, with dependence, on certain medicines — about not drinking at all.

When to see a doctor

Right away — call 999 in the UK, 911 in the US, 112 in the EU: signs of alcohol poisoning — confusion, being impossible to wake, vomiting while drowsy, slow or irregular breathing, a seizure, pale or blue-tinged skin. Do not leave the person alone; what to do while you wait is in how alcohol leaves the body. Also right away: seizures, hallucinations, confusion or severe shaking in someone who has stopped drinking after heavy regular use (NHS, UK), and unusual drowsiness or slow breathing after alcohol taken with sleeping pills, sedatives or opioids (NIAAA, US).

Soon — the same day or next: you are pregnant, drank before you knew and are worried — talk to your midwife or doctor; the UK Chief Medical Officers say the risk from a small amount is probably low. You drink while taking warfarin, diabetes medicines, painkillers or antihistamines — check with a pharmacist or doctor.

Routinely, with your GP or doctor: you want a drink in the morning, find it hard to stop once you start, or only a drink relieves the shakes and anxiety of the morning after; you regularly drink above your country's guideline; loud snoring with pauses in breathing and daytime sleepiness; sleep problems lasting months.

What is happening

Sleep. Alcohol is a sedative. A 2025 meta-analysis of 27 studies found it delays and shortens REM (dreaming) sleep already at low doses, more so as the dose rises, while faster sleep onset appeared only after high doses (Gardiner et al., 2025). As the liver clears the alcohol, the second half of the night becomes more broken (Ebrahim et al., 2013). The sedative effect fades within a few nights of regular use (Roehrs and Roth, 2001), and heavier drinking is linked to a higher risk of sleep apnoea (Simou et al., 2018).

Cancer and dose. Alcohol causes at least seven types of cancer, including bowel cancer and breast cancer in women; in the WHO European Region about half of alcohol-related cancers occur in people drinking light or moderate amounts (WHO, 2023). The US National Cancer Institute, citing the Surgeon General's 2025 advisory, puts the risk of developing one of these cancers by age 80 at about 17 in 100 women drinking less than one drink a week, 19 with one a day and 22 with two; for men, 10, 11 and 13 in 100.

The glass of red for the heart. The UK Chief Medical Officers found any protective effect smaller and less certain than once thought; a 2023 meta-analysis of 107 cohort studies, after correcting for biases, found low drinking not linked to longer life than never drinking (Zhao et al., 2023). No source here recommends drinking for health.

Guidelines differ by country, and so does a drink.

UK (Chief Medical Officers, 2016): to keep risk low, do not regularly drink more than 14 units a week, spread over three or more days. A unit is 8 g of pure alcohol: a 25 ml shot of 40% spirit is 1 unit, a 125 ml glass of 12% wine is 1.5, a pint of 5.2% lager is 3 (NHS).
US (Dietary Guidelines for Americans 2025–2030): drink less for better health, with no numeric limit; the earlier two-and-one daily figures are no longer in them. A US standard drink is 14 g, so two American drinks hold more alcohol than two British units.

What to do

Count in your country's measure, not in glasses, and keep several drink-free days a week; drink slowly, with food and water (UK CMO).
Do not use alcohol to fall asleep. For lasting insomnia the first-line treatment is cognitive behavioural therapy (American Academy of Sleep Medicine, 2021); see can't fall asleep in twenty minutes.
Try a dry week or month and notice your sleep and mornings — unless you might be dependent. If you drink heavily every day, get shakes or sweats when you stop, or need a morning drink, stopping suddenly can be dangerous: withdrawal can start within 6–12 hours (NHS, UK). Talk to a doctor first. See use, habit and addiction and a substance to relax every evening.
Get help early: in the UK, your GP or Drinkline on 0300 123 1110.
Related pages: what a hangover actually is, caffeine half-life, paracetamol vs ibuprofen, know your blood pressure.

When this is not the case

Do not drink at all if you are pregnant or trying to conceive — UK, US and Russian guidance all advise avoiding alcohol; if you are breastfeeding it is safest not to drink, and never share a bed or sofa with your baby after any alcohol (NHS). Also: with alcohol dependence or when you cannot control the amount; with medicines or conditions that interact with alcohol (US Dietary Guidelines); before driving — any amount affects driving (UK Highway Code); and in the US under 21. Older adults clear alcohol more slowly and are more exposed to interactions with medicines (NIAAA).

Sources

Checked: 24 September 2026

Alcohol, Honestly: Dose, Risk, Sleep and Who Should Not Drink at All