Alcohol and muscle growth: how much it really affects your muscles, sleep and recovery
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A binge after training cuts muscle protein synthesis by up to 37%, but one or two beers come nowhere near what has been studied. What the studies say, how much it takes before you notice it, how it affects sleep and how many calories each drink has.
After a leg and cycling workout, eight active men drank the equivalent of about twelve drinks over the following hours. Even though they also took 25 grams of whey protein, their muscle protein synthesis was 24% lower than when they took the same protein without alcohol. When the alcohol was paired with carbohydrates only, the drop reached 37%.
That study, published in 2014 by Parr and colleagues, is the reason people say alcohol "kills your gains". But the dose matters a lot, and the full story is more nuanced. Here's what alcohol does to muscle, how much it takes before you notice it, what happens to recovery and sleep, and how to drink, if you drink, so it interferes as little as possible with your training.
Alcohol and muscle growth: how alcohol affects your muscles
Muscle grows when, over the sum of the days, protein synthesis outpaces breakdown. Strength training activates the mTOR pathway, the master switch for that synthesis. The review by Levitt, Luk and Vingren (2022) sums up what is known: alcohol at high doses puts the brakes on that pathway while training switches it on, and the outcome depends on the amount, on diet and on sex, among other factors. Eating protein can partly offset the brake, but not completely.
On top of that come three indirect effects: alcohol worsens sleep, it provides calories without nutrients that displace other foods and, often, nights out drinking end with poorer-quality food and less desire to train the next day.
What studies in people who train show
Human studies are few and almost all use high doses, so it's worth reading them with close attention to the amounts.
| Study | Participants and dose | Result |
|---|---|---|
| Parr and colleagues, 2014 | 8 active men; 1.5 g of alcohol per kilo (about 12 drinks) | Muscle protein synthesis 24% lower with protein and 37% lower with carbohydrates |
| Barnes and colleagues, 2010 | 10 men; 1 g/kg after a very damaging eccentric exercise | Strength loss at 36 h of 41-45% versus 26-32% without alcohol |
| Levitt and colleagues, 2017 | 13 trained women; 1.09 g per kilo of fat-free mass | No effect on strength recovery or inflammation |
| Levitt and colleagues, 2020 | 10 trained men; same dose, after eccentric squats | No effect on power or muscle soreness at 24-48 h |
| Vingren and colleagues, 2013 | 8 trained men; same dose, after squats | Higher testosterone between 2 and 5 hours afterwards, without that meaning more muscle |
The conclusion from the table is less alarmist than what you usually hear: binge drinking clearly does interfere with protein synthesis and with recovery from a very damaging effort, whereas moderate doses after regular training, in trained people, have shown barely any short-term effects. Levitt and colleagues also point to a possible difference between the sexes: in their study with women, alcohol did not worsen recovery, unlike what had previously been observed in men.
The testosterone finding deserves a clarification. In the study by Vingren (2013), free testosterone was higher in the following hours with alcohol than without it. It's not good news in disguise: that acute spike has not been linked to more muscle, and chronic heavy drinking has the opposite effect on hormones. We explain it in how to boost testosterone naturally.
How much alcohol it takes to affect your muscles
There's no exact threshold, but the doses in the studies help you get your bearings. In Spain, a standard drink contains about 10 grams of alcohol. For a 75-kilo person:
- 1 g/kg, the dose in the Barnes study, is about 75 grams: seven or eight drinks.
- 1.5 g/kg, the one in the Parr study, is more than 110 grams: eleven drinks or more.
- One or two drinks are well below what has been studied, and there's no evidence that they noticeably affect protein synthesis.
What really holds back your progress isn't a beer, it's the pattern: several nights of heavy drinking a month, each followed by worse sleep, erratic eating and a weak or skipped workout. The cumulative effect is what shows on the scales and in the mirror.
Alcohol, sleep and recovery
This is where alcohol does harm even at low doses. The meta-analysis by Gardiner and colleagues (2025), covering 27 studies, found that alcohol delays the onset of REM sleep and shortens it, and that this effect already appears at low doses (up to 0.5 g/kg, about two drinks) and gets worse the more you drink. At high doses (about five drinks or more), you fall asleep sooner, but at the cost of disrupting REM even further.
In other words, the feeling of "sleeping like a log" after a few drinks is misleading: the architecture of your sleep gets worse. And sleep is one of the central pieces of recovery, as we explain in sleep and sports performance.
The calories in alcohol
Alcohol provides 7 kcal per gram, almost as much as fat, and it doesn't fill you up. If you're in a calorie deficit to lose fat, the calories from one night out can wipe out a good part of the week's deficit. These are the calories provided by the alcohol alone in each drink; the carbohydrates in beer or in the soft drink of a mixed drink add more:
| Drink | Volume and strength | Alcohol | Kcal from alcohol |
|---|---|---|---|
| Small glass of beer | 200 ml at 5% | 8 g | 55 |
| Bottle of beer | 330 ml at 5% | 13 g | 90 |
| Glass of wine | 150 ml at 13% | 15 g | 108 |
| Mixed drink | 50 ml of spirits at 40% | 16 g | 110 + the mixer |
| Shot | 30 ml at 40% | 9.5 g | 66 |
Five bottles of beer in one night come to about 450 kcal from alcohol alone, and around 700 counting the carbohydrates in the beer, before adding whatever you eat alongside.
How to drink so it affects your training as little as possible
- Less is better, and it doesn't have to be zero. The difference between one or two drinks and a binge is huge for your muscles.
- Eat protein that day. In the Parr study, taking protein with the alcohol reduced the drop in muscle synthesis (24% versus 37%). Spreading your daily protein across several meals is still the foundation.
- Avoid drinking right after the hardest session of the week, especially if it was very eccentric or left you very sore: that's where studies show the greatest strength loss.
- Hydrate and have a good dinner before drinking, and alternate with water.
- Protect your sleep: the earlier you stop drinking relative to bedtime, the less it will disrupt REM.
- Don't train hungover chasing a record: the next day, an easy or technique session is better than a failed one.
If you notice that alcohol takes up a significant place in your week or you find it hard to control, your muscles are not what matters most: talk to your doctor or a healthcare professional.
To make every session really count even when your week isn't perfect, the Progrevia generator tailors your routine to the days you can train and to your goal.
- Parr EB, Camera DM, Areta JL, Burke LM, Phillips SM, Hawley JA, et al. Alcohol ingestion impairs maximal post-exercise rates of myofibrillar protein synthesis following a single bout of concurrent training. PLoS One. 2014;9(2):e88384.
- Barnes MJ, Mündel T, Stannard SR. Post-exercise alcohol ingestion exacerbates eccentric-exercise induced losses in performance. European Journal of Applied Physiology. 2010;108(5):1009-1014.
- Levitt DE, Luk HY, Duplanty AA, McFarlin BK, Hill DW, Vingren JL. Effect of alcohol after muscle-damaging resistance exercise on muscular performance recovery and inflammatory capacity in women. European Journal of Applied Physiology. 2017;117(6):1195-1206.
- Levitt DE, Idemudia NO, Cregar CM, Duplanty AA, Hill DW, Vingren JL. Alcohol after resistance exercise does not affect muscle power recovery. Journal of Strength and Conditioning Research. 2020;34(7):1938-1944.
- Vingren JL, Hill DW, Buddhadev H, Duplanty A. Postresistance exercise ethanol ingestion and acute testosterone bioavailability. Medicine and Science in Sports and Exercise. 2013;45(9):1825-1832.
- Levitt DE, Luk HY, Vingren JL. Alcohol, resistance exercise, and mTOR pathway signaling: an evidence-based narrative review. Biomolecules. 2022;13(1):2.
- Gardiner C, Weakley J, Burke LM, Roach GD, Sargent C, Maniar N, et al. The effect of alcohol on subsequent sleep in healthy adults: a systematic review and meta-analysis. Sleep Medicine Reviews. 2025;80:102030.
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Frequently asked questions
Does alcohol stop you building muscle?
Binge drinking does interfere: in the study by Parr (2014), about 12 drinks after training reduced muscle protein synthesis by 24% even when protein was taken. Moderate doses, such as one or two drinks, have not shown noticeable short-term effects in trained people.
How long after training can I drink alcohol?
There's no established minimum time. What matters most is the amount and eating protein that day. It's best to avoid heavy drinking after the hardest or most damaging session of the week, because that's when studies observe the greatest strength loss.
Is beer fattening if I train?
Alcohol provides 7 kcal per gram: a bottle of beer has about 90 kcal from alcohol alone, and close to 140 counting the carbohydrates. If you're in a deficit, several beers can cancel out a good part of the week's deficit.
Does alcohol affect sleep even in small amounts?
Yes. According to the meta-analysis by Gardiner (2025), covering 27 studies, alcohol reduces REM sleep even at low doses, of about two drinks, and the effect gets worse the more you drink.
Informational content based on the available scientific evidence: it does not replace advice from a healthcare professional. If you have an injury or a medical condition, or are pregnant, check with one before changing your training or diet.
