Study analysis · Journal of the International Society of Sports Nutrition · 2013
Stop drinking your protein shake right after the gym — science says it’s pointless.
It doesn’t matter when you drink your protein shake — what matters is how much you eat all day.
Overview
What the study found
The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.
In simple terms
This study looked at lots of experiments where people lifted weights and drank protein at different times. It found that drinking protein right before or after working out doesn’t make you stronger or bigger than just drinking enough protein during the day — so timing doesn’t matter as much as you thought.
What’s the bottom line?
It doesn't matter if you drink your protein shake right before or after working out — what matters is how much protein you eat all day.
How strong is this study?
This study did a really good job — it checked many high-quality experiments, made sure they were fair, and used math to remove confusing factors like how much protein people ate. That makes the results trustworthy, even though we don’t know if everyone was blinded.
0 / 100
- COI disclosureconflicts of interest not disclosed
- Data availabilitydata not shared
- Code availabilitycode not shared
79 / 100
- Randomization+20/20
- Blindingblinding unclear
- Control group+15/15
- Sample size (n=525)+18.6/20
- Follow-up+10/10
100 / 100
77 / 100
- P-values+15/15
- Effect size+20/20
- Confidence intervals+15/15
- Pre-registrationnot pre-registered
Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.
Where it sits
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 567 / 100
Probability of being correct
The highest quality evidence. Systematic reviews and meta-analyses that pool randomized controlled trials, giving the most reliable summary of experimental evidence.
This design can establish causation. The meta-analysis includes RCTs, but blinding is unknown in all included studies, and the primary conclusion is that protein timing has no significant effect after adjusting for total protein intake — which is a confounder. Causation is inferred for the lack of effect of timing, not for any positive effect.
Key takeaways
- 01
You need at least 1.6 grams of protein per kilogram of body weight daily.
- 02
Every extra 0.5 g/kg/day gives about a 0.2 boost in muscle growth.
- 03
Timing within 1 hour of workout doesn't help if total protein is the same.
- 04
Yes — if you hit your daily protein goal, skipping the post-workout shake won't hurt your gains.
Surprising findings
- Most studies claiming protein timing worked didn’t even match total protein intake between groups.For years, media and supplements sold timing as key — but the evidence was built on studies that gave one group more protein overall, not better timing.
- The effect size boost from extra protein was consistent — 0.2 per 0.5 g/kg/day — regardless of when it was consumed.This suggests muscle growth responds linearly to total protein, not to spikes from peri-workout intake — contradicting biochemical models of acute synthesis.
Practical takeaways
Aim for at least 1.6 g of protein per kg of body weight daily — spread it evenly across meals. No need to rush a shake after lifting.
If you’re under 1.6 g/kg/day, timing won’t fix low intake — fix the total first.
high confidenceIf you like drinking a shake after the gym — keep doing it! It’s not harmful, just unnecessary if your daily protein is on point.
The study didn’t test extreme timing (e.g., fasting before workout), so results may not apply to intermittent fasting protocols.
medium confidenceWhy this study matters
Total Protein Trumps Timing
The meta-analysis of 20–23 studies found that total daily protein intake ≥1.6 g/kg/day was the strongest predictor of muscle growth — not when you ate it. Each extra 0.5 g/kg/day boosted muscle gains by ~0.2 in effect size.
Most people waste time stressing over the ‘anabolic window’ — this shows they could eat protein at breakfast, lunch, or bedtime and get the same results.
The 1-Hour Window is a Myth
Protein timing within 1 hour before or after training showed no significant benefit when total protein was matched. Only 3 of the 23 studies actually controlled for total intake — meaning most past ‘proof’ of timing was flawed.
Gym culture has sold the idea of a 30-minute anabolic window for decades — this study says it’s not real if you’re hitting your daily protein goal.
Trained Athletes? We Don’t Know Yet
Only 4 studies included trained individuals — meaning we can’t say for sure if elite lifters benefit from timing. The study admits this is a major limitation.
If you’re a pro athlete or bodybuilder, this study doesn’t fully apply to you — and that’s a huge gap in the science.
Want the whole report?
Detailed mode opens the full scientific breakdown — every score component, the methodology, conflicts of interest, the evidence analysis behind each claim, and the raw study data.
Overview
What the study found
The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
It doesn't matter if you drink your protein shake right before or after working out — what matters is how much protein you eat all day.
Research results
You need at least 1.6 grams of protein per kilogram of body weight daily. Every extra 0.5 g/kg/day gives about a 0.2 boost in muscle growth. Timing within 1 hour of workout doesn't help if total protein is the same.
What this means - more context
Yes — if you hit your daily protein goal, skipping the post-workout shake won't hurt your gains.
To determine whether timing protein intake around resistance training enhances muscle strength or hypertrophy beyond adequate total daily protein intake.
This meta-analysis of 20–23 RCTs found no significant benefit of protein timing (peri-workout intake) on strength or hypertrophy when total daily protein was controlled. Total daily protein intake (≥1.6 g/kg/day) was the strongest predictor of hypertrophy gains, with each 0.5 g/kg/day increase linked to ~0.2 increase in effect size. Timing effects were confounded in most studies due to unmatched protein intake.
Methods Used
Meta-analysis of 478 (strength) and 525 (hypertrophy) subjects across 20–23 randomized controlled trials; used multi-level meta-regression to control for covariates including total protein intake, training status, and study design.
Main Finding
Total daily protein intake ≥1.6 g/kg/day is the strongest predictor of muscle hypertrophy, with each 0.5 g/kg/day increase associated with a ~0.2 increase in effect size; protein timing within 1 hour before/after training showed no significant benefit when total protein was matched.
Confidence Level
Moderate. High statistical power and meta-regression control for confounders strengthen findings, but limited studies matched protein intake (n=3) and few involved trained individuals (n=4), reducing certainty on subgroup effects.
Study Flags
Red Flags
- •Most studies did not match total protein intake between groups, confounding timing effects
- •Only 3 studies directly compared peri-workout vs. other timing with matched protein
- •Limited data on trained individuals (n=4 studies)
No biological mechanisms were identified in this study. This may be an epidemiological, observational, or survey-based study that reports associations rather than proposing causal biological pathways.
Surprising Findings
Most studies claiming protein timing worked didn’t even match total protein intake between groups.
For years, media and supplements sold timing as key — but the evidence was built on studies that gave one group more protein overall, not better timing.
Practical Takeaways
Aim for at least 1.6 g of protein per kg of body weight daily — spread it evenly across meals. No need to rush a shake after lifting.
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 567 / 100
Probability of being correct
The highest quality evidence. Systematic reviews and meta-analyses that pool randomized controlled trials, giving the most reliable summary of experimental evidence.
Human Meta-Analysis
Subject
Moderate probability
on the GRADE evidence scale
This study looked at lots of experiments where people lifted weights and drank protein at different times. It found that drinking protein right before or after working out doesn’t make you stronger or bigger than just drinking enough protein during the day — so timing doesn’t matter as much as you thought.
Strengths
- High-quality RCTs included (mean PEDro score 8.7/10)
- Large sample size (525 subjects for hypertrophy)
- Use of meta-regression to control for confounders (protein intake, training status, blinding, etc.)
Weaknesses
- Blinding status unknown in all included studies — violates GRADE rule to not assume blinding
- Only 3 studies matched total protein intake, limiting ability to isolate timing effect
- Heterogeneity in control group timing (some gave protein ≤2h post-exercise, others later)
Methodology
Evidence Keywords
Statistical Reporting
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
It doesn't matter if you drink your protein shake right before or after working out — what matters is how much protein you eat all day.
Research results
You need at least 1.6 grams of protein per kilogram of body weight daily. Every extra 0.5 g/kg/day gives about a 0.2 boost in muscle growth. Timing within 1 hour of workout doesn't help if total protein is the same.
What this means - more context
Yes — if you hit your daily protein goal, skipping the post-workout shake won't hurt your gains.
To determine whether timing protein intake around resistance training enhances muscle strength or hypertrophy beyond adequate total daily protein intake.
This meta-analysis of 20–23 RCTs found no significant benefit of protein timing (peri-workout intake) on strength or hypertrophy when total daily protein was controlled. Total daily protein intake (≥1.6 g/kg/day) was the strongest predictor of hypertrophy gains, with each 0.5 g/kg/day increase linked to ~0.2 increase in effect size. Timing effects were confounded in most studies due to unmatched protein intake.
Methods Used
Meta-analysis of 478 (strength) and 525 (hypertrophy) subjects across 20–23 randomized controlled trials; used multi-level meta-regression to control for covariates including total protein intake, training status, and study design.
Main Finding
Total daily protein intake ≥1.6 g/kg/day is the strongest predictor of muscle hypertrophy, with each 0.5 g/kg/day increase associated with a ~0.2 increase in effect size; protein timing within 1 hour before/after training showed no significant benefit when total protein was matched.
Confidence Level
Moderate. High statistical power and meta-regression control for confounders strengthen findings, but limited studies matched protein intake (n=3) and few involved trained individuals (n=4), reducing certainty on subgroup effects.
Study Flags
Red Flags
- •Most studies did not match total protein intake between groups, confounding timing effects
- •Only 3 studies directly compared peri-workout vs. other timing with matched protein
- •Limited data on trained individuals (n=4 studies)
No biological mechanisms were identified in this study. This may be an epidemiological, observational, or survey-based study that reports associations rather than proposing causal biological pathways.
Surprising Findings
Most studies claiming protein timing worked didn’t even match total protein intake between groups.
For years, media and supplements sold timing as key — but the evidence was built on studies that gave one group more protein overall, not better timing.
Practical Takeaways
Aim for at least 1.6 g of protein per kg of body weight daily — spread it evenly across meals. No need to rush a shake after lifting.
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 567 / 100
Probability of being correct
The highest quality evidence. Systematic reviews and meta-analyses that pool randomized controlled trials, giving the most reliable summary of experimental evidence.
Human Meta-Analysis
Subject
Moderate probability
on the GRADE evidence scale
This study looked at lots of experiments where people lifted weights and drank protein at different times. It found that drinking protein right before or after working out doesn’t make you stronger or bigger than just drinking enough protein during the day — so timing doesn’t matter as much as you thought.
Strengths
- High-quality RCTs included (mean PEDro score 8.7/10)
- Large sample size (525 subjects for hypertrophy)
- Use of meta-regression to control for confounders (protein intake, training status, blinding, etc.)
Weaknesses
- Blinding status unknown in all included studies — violates GRADE rule to not assume blinding
- Only 3 studies matched total protein intake, limiting ability to isolate timing effect
- Heterogeneity in control group timing (some gave protein ≤2h post-exercise, others later)
Methodology
Evidence Keywords
Statistical Reporting
Scoring
How strong is this study?
This study did a really good job — it checked many high-quality experiments, made sure they were fair, and used math to remove confusing factors like how much protein people ate. That makes the results trustworthy, even though we don’t know if everyone was blinded.
0 / 100
- COI disclosureconflicts of interest not disclosed
- Data availabilitydata not shared
- Code availabilitycode not shared
79 / 100
- Randomization+20/20
- Blindingblinding unclear
- Control group+15/15
- Sample size (n=525)+18.6/20
- Follow-up+10/10
100 / 100
77 / 100
- P-values+15/15
- Effect size+20/20
- Confidence intervals+15/15
- Pre-registrationnot pre-registered
Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.
Where it sits
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 567 / 100
Probability of being correct
The highest quality evidence. Systematic reviews and meta-analyses that pool randomized controlled trials, giving the most reliable summary of experimental evidence.
This design can establish causation. The meta-analysis includes RCTs, but blinding is unknown in all included studies, and the primary conclusion is that protein timing has no significant effect after adjusting for total protein intake — which is a confounder. Causation is inferred for the lack of effect of timing, not for any positive effect.
Standing
Who’s using this study?
The videos and claims on this site that lean on this study, and the researchers who wrote it.
1 video from House of Hypertrophy cite this study, drawing 1 claim from it.
- Very strong evidence
Randomized or controlled trials support this claim, alongside consistent supporting evidence.
Evidence
Authored by
3 researchersIf this is your work, this is how we attribute it on Fit Body Science. Brad Jon Schoenfeld is listed as the lead author.