Dry January Benefits Before 2027: What 94 Drinkers Gained in a Month Off, and Who Should Skip the Cold Turkey
Ninety-four people stopped drinking for a month, and their insulin resistance fell by about a quarter. That’s the number behind most Dry January benefits claims, and it comes from a real hospital study. It also comes from people who’d been drinking roughly 32 units a week beforehand, which is more than double the NHS limit of 14.
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So the useful question isn’t whether a month off helps. It’s whether it helps you, and that depends almost entirely on what you were pouring before 1 January.
Dry January benefits: what 94 drinkers actually gained
The study most people quote is Mehta and colleagues, published in BMJ Open in 2018, run at a single tertiary centre. They recruited healthy adults who drank above a set threshold (more than 64g of alcohol a week for men, 48g for women) and had no known liver disease or alcohol dependence. Ninety-four planned to go without for a month. Another 47 planned to carry on drinking and acted as the comparison group.
After the month, the abstainers had lower insulin resistance (down 25.9%), lower systolic blood pressure (down 6.6%), lower diastolic pressure (down 6.3%) and had lost 1.5% of their body weight. Two cancer-related growth factors, VEGF and EGF, dropped by 41.8% and 73.9%. Every one of those changes had a p-value under 0.001. The drinkers who carried on showed no significant change in any of them. The authors also adjusted for diet, exercise and smoking and say those didn’t explain the results (abstract on BMJ Open).
Those are strong numbers. But the study wasn’t randomised. People chose their own group, which means the sort of person who signs up to stop for a month may differ from the sort who doesn’t, in ways no statistical adjustment fully catches. It’s a good observational study. It isn’t proof.
The spread matters too. The abstract gives the middle half of results alongside each headline figure, and for insulin resistance that range ran from a 48.6% fall to a 0.3% rise. In other words, roughly a quarter of the abstainers saw no improvement at all on the study’s main measure. The 25.9% is the typical result, not a guarantee, and anyone selling Dry January as a sure thing has skipped that line of the abstract.
And one thing I couldn’t see in the abstract: the liver test results. Plenty of articles promise a “liver reset” from Dry January. The figures the abstract leads with are metabolic and blood pressure numbers, and I’d be guessing if I told you what happened to liver function from that page alone.
The 32-unit problem
The abstainers’ baseline drinking averaged 258.2g of alcohol a week. The NHS counts one unit as 8g of pure alcohol, so that’s about 32 units. For scale, the NHS says 14 units is roughly six pints of average-strength beer or ten small glasses of lower-strength wine, and a 750ml bottle of 13.5% wine is ten units on its own (NHS guidance on units).
Three bottles of wine a week, then. Or a pint-and-a-half a night plus a heavy weekend.
That’s the group that saw the big drops. If you’re having two glasses of wine on a Friday and a pint at Sunday lunch, you’re nowhere near that starting line, and the same improvements aren’t a safe bet. You may well sleep better and save a few quid. But a 26% fall in insulin resistance? The study can’t promise that to a light drinker, because it didn’t test one.
This is the bit the Dry January marketing skips. The people with most to gain are the ones drinking well past the guideline, and they’re also the people least likely to say so on a sign-up form.
What the surveys say, and what they can’t
The best-known behaviour research comes from the University of Sussex, which followed more than 6,000 people between January and August 2019. Dry January participants, who’d registered with Alcohol Change UK, were still drinking less in August than they had at the start of the year. A general-population comparison group showed no fall in drinking over the same period. Those who took part reported higher confidence in saying no to a drink, and that confidence was still there six months later (University of Sussex).
The self-reported extras are what get quoted in January. In that 2019 cohort, 84% said they’d saved money, 80% felt more in control of their drinking and 72% said they slept better. Alcohol Change’s own evidence page lists slightly different figures for the same research (86%, 81% and 70%), which tells you how loosely these numbers get passed around.
Now the awkward arithmetic. The Dry January group had 3,171 people in January, 1,342 in February and 1,168 in August. By my sums, only about 37% of the January sign-ups were still answering by the summer. The people who stayed are probably the ones for whom it went well. That doesn’t make the findings wrong, but it does mean “participants drank less six months later” describes the participants who stuck around, not everyone who tried.
So treat the survey benefits as encouraging, self-reported and self-selected. Useful. Not gospel.
A month off is not a detox
Here’s my position, and you can disagree with it. Dry January is overrated as a body reset and underrated as an experiment.
And it’s worth saying plainly that four weeks is a short window. The study followed people for the month they’d planned and no longer, so what happened to their insulin resistance or blood pressure by spring is simply unknown. I’d rather say that than imply a lasting change the paper doesn’t measure.
The word “detox” implies your body is carrying something that a month clears out, after which you’re free to start again. Nothing in the study above says that. What it shows is that for heavy-ish drinkers, a few weeks without alcohol moved some risk markers in the right direction. Fine. But markers that moved down in four weeks tend to drift back up if the drinking comes back at the same level in February.
The more interesting payoff is behavioural. A month without alcohol shows you what you actually use it for. Is it winding down after work? Is it the only way you know to be at a party? Is it just what happens at 6pm in your house? People who find that out in January have something to work with. People who white-knuckle through to 31 January and go straight back to the usual have, as far as the evidence goes, mostly bought themselves a month.
That’s why the Sussex finding matters more than the blood-pressure one. Drinking less in August is a result you can build on. A lower blood pressure reading in February that’s gone by April isn’t.
Who shouldn’t just stop
This one’s short, because it matters. If you drink heavily every day, or you get shaky or anxious when you go without, don’t stop overnight on the strength of a January challenge. Stopping suddenly after heavy, regular drinking can cause withdrawal that’s dangerous. Speak to your GP first. The Mehta study itself excluded anyone with alcohol dependence, so it tells you nothing about that group.
The same goes if you’re on medication that interacts with alcohol or you have a liver condition. Ask the person who prescribed it. A generic Dry January app can’t.
For everyone else, the risk of trying is low, and the downside of failing is a Tuesday-night pint.
The sign-up page matters more than your willpower
Here’s a finding that should change how you approach it. The Sussex team found that people who signed up and used the Dry January website, the Try Dry app or the email support were twice as likely to complete the month without a drink as people who tried to stop without registering. Alcohol Change UK says the free tools double your chances compared to going it alone.
Be a little careful with that. Again, people who register might be more motivated to begin with, so the “twice as likely” may not all be down to the app. Still, the tools cost nothing, and the cost of a bad month is small. I’d sign up.
The scale of it is worth a look too. A January 2026 survey by drinks brand TRIP and CensusWide put the number of Britons planning a month off at 17.5 million, and called it the biggest Dry January on record. Treat that with some salt, since the people running the survey sell an alcohol-free drink. Alcohol Change UK, for its part, says more than 200,000 people took part using its free tools in 2025. Those aren’t the same year or the same measure, but the gap tells its own story: millions say they’ll do it, and a far smaller number sign up for the thing that doubles their odds.
Sleep, energy and the other claims
The Sussex surveys found large shares of participants saying they slept better (72% in the 2019 cohort), had more energy. Those are self-reports, but they’re also the benefits most people notice first, and they’re plausible. Alcohol is known to fragment sleep even when it helps you drop off, which is why the first week without it can feel odd and the third week can feel noticeably better.
If sleep is your main reason for trying this, track it sensibly. Our look at sleep tracker accuracy explains how much to trust a ring or watch when it tells you your sleep score has jumped. And if you’re swapping the evening drink for a coffee, check our piece on the caffeine cut-off time first, because a 4pm flat white can undo the sleep you’ve just gained.
Weight is the claim I’d be most sceptical of. In the study, the abstainers lost 1.5% of body weight. For an 80kg person that’s 1.2kg. Worth having, but it’s not a transformation, and plenty of people make up the calories with biscuits and alcohol-free beer. If weight loss is the goal, a month off alcohol is a small tool and not a plan.
A better plan than January alone
The research suggests a month off is a good start for people who drink above the guideline. It doesn’t suggest it’s a good finish. If I were doing this, I’d treat the 31 days as a baseline and decide in advance what February looks like.
The simplest version is the NHS one: keep to no more than 14 units a week, spread over three or more days, with several drink-free days. It’s boring advice. It also happens to be the part the January campaign rarely mentions. A cap you actually keep beats a clean month followed by a binge in February, and the Sussex numbers hint at the same thing, since drinking was lower in August for those who stayed with it.
A few practical bits that cost nothing:
- Pick your replacement drink before the first Friday, not on it. Standing at a bar with no plan is how most Januarys end.
- Tell one person, and make it someone who’ll ask. Not someone who’ll say “go on, one won’t hurt”.
- Count units for the first week of February, honestly. People who’ve been dry for a month tend to underestimate how fast it adds up again.
- Check in on the rest of your health too. Our Movember men’s health checks piece covers the blood pressure and other checks worth booking, and a January with a clean baseline is a decent moment to get them done.
If you’d rather have the shorter version of the who-shouldn’t-quit-cold warning, our Sober September piece covers it.
So, should you do it?
If you drink more than 14 units a week, yes, and sign up to the free tools. The evidence that you’ll feel and measure better is decent, even if it’s observational. If you drink well under the guideline, you’re doing it for the experiment and the savings, and that’s a perfectly good reason, but don’t expect the study numbers.
Either way, the month is a means, not the end. What would you do differently on 1 February if you knew January had gone well?
