Does alcohol kill gains?
A big night after training can. In a 2014 study, 8 active men lifted and cycled, then drank about 8.5 US drinks over the next few hours. Their muscle building fell 24% when the alcohol came with protein, and 37% when it came with carbs instead.
Gym talk goes two ways on this. Some people say a few beers after a game is harmless, and others say one glass of wine wipes out the workout. The main study on it sits at the far end. It tested a team-sport binge, and it found a real cost. Nobody has run the same test with one or two drinks.
What we’d do
Keep big nights away from your hardest training days, and eat protein after training either way. If you have a drink after a session, keep it to one or two, and make it a day you’re resting tomorrow. A heavy night costs your muscles, your sleep and the next day’s workout.
What the study did
Researchers at RMIT University in Melbourne had 8 active men, average age 21 and about 175 lb, do a hard mixed session three times: 8 sets of 5 heavy leg extensions, 30 minutes of steady cycling and ten 30-second sprints on the bike. Each time they drank something different afterward.
| After training | Change in muscle building, against protein alone |
|---|---|
| Protein shake, no alcohol | the baseline |
| Alcohol with the same protein | 24% lower |
| Alcohol with carbs instead of protein | 37% lower |
The alcohol was 1.5 g per kg of body weight, vodka with orange juice in six drinks over three hours, starting an hour after training. The paper calls it 12 standard drinks, counted in Australian drinks of 10 g. In US drinks it’s about 8.5. The researchers chose it because it matched what team athletes report drinking on a binge.
Muscle building still went up after training in every version, by about 29 to 109% over rest. The alcohol cut how much.
Why it happens
After a hard session, your muscles are a construction site and protein is the delivery of bricks. Alcohol keeps part of the crew off the job. In the study, a key switch for muscle building (a protein called mTOR) was less active two hours after training when alcohol was in the mix, even with the protein there.
What else a big night costs
Sleep is when you recover, and a drinking night is a worse one. In 20,968 WHOOP members, more drinks came with shorter sleep and less activity the next day. NIAAA counts 5 or more drinks on any day as heavy drinking for a man and 4 or more for a woman, and the study’s dose was well past both.
What isn’t known
The study had 8 men and one very large dose. It didn’t test women, smaller amounts, or whether weeks of training add up to less muscle. What it shows is that a big night right after hard training cuts that day’s muscle building, even when you get your protein.
3 sources
- Parr EB and others, Alcohol ingestion impairs maximal post-exercise rates of myofibrillar protein synthesis following a single bout of concurrent training, PLoS One, 2014pubmed.ncbi.nlm.nih.gov
- Grosicki GJ and others, Real-world effects of alcohol on heart rate, sleep, and physical activity by age and sex, PLOS Digital Health, 2026 (funded by WHOOP)pubmed.ncbi.nlm.nih.gov
- National Institute on Alcohol Abuse and Alcoholism, Drinking Levels and Patterns, updated January 2026niaaa.nih.gov
