Study analysis · The Journal of sports medicine and physical fitness · 2019
Creatine makes you stronger—but also more sore? Here's why that's actually a good thing.
Taking creatine while lifting weights helps you get stronger faster, but it also makes your muscles more damaged—because you're training harder.
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 showed that guys who took creatine while lifting weights got stronger faster than guys who took a fake pill. But it doesn't prove creatine works for everyone — just these 18 young men. It's like saying 'this snack helped these 5 kids run faster' — it might help others, but we don't know for sure.
What’s the bottom line?
Taking creatine while lifting weights helps you lift heavier faster, but it doesn't protect your muscles—it actually makes them more sore.
How strong is this study?
This study did a good job by randomly giving some guys creatine and others a placebo, and nobody knew who got what — that makes it fair. But it only had 18 people, so if one person had a weird reaction, it could mess up the results. Bigger studies with more people would be more trustworthy.
0 / 100
- COI disclosureconflicts of interest not disclosed
- Data availabilitydata not shared
- Code availabilitycode not shared
77 / 100
- Randomization+20/20
- Blinding+15/15
- Control group+15/15
- Sample size (n=18)+1.7/20
- Follow-up+10/10
100 / 100
23 / 100
- P-values+15/15
- Effect sizeno effect size reported
- Confidence intervalsno confidence intervals
- 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 553 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
This design can establish causation. This is a randomized controlled trial with double blinding and a control group, which allows for causal inference between creatine supplementation and increased strength. However, the small sample size (n=18) and limited demographic (young males only) constrain the strength of generalizability and increase vulnerability to random error.
No Conflicts
No conflicts of interest identified
No conflicts of interest or funding statements were disclosed in the article; no industry ties or funder involvement are evident.
The article is openly accessible and appears to be independently conducted. No author affiliations suggest industry employment, and no funding sources are listed. However, absence of a COI or funding statement limits certainty; best practice would require explicit disclosure.
Key takeaways
- 01
After 2 weeks, creatine users got stronger on 3 exercises; after 8 weeks, they got stronger on 4 exercises.
- 02
Muscle damage markers were higher in creatine users than placebo users.
- 03
Yes—getting stronger faster with more muscle soreness means creatine lets you train harder, which may help build more muscle over time.
Surprising findings
- Creatine increased muscle damage markers (CK and LDH) instead of reducing them.Most assume creatine reduces soreness or protects muscles; this study shows the opposite—higher damage markers suggest greater training intensity, not less recovery.
Practical takeaways
Take 0.07g of creatine per kg of body weight daily during resistance training to boost strength gains in compound lifts like bench press and leg press.
Results only apply to young males; effects in women, older adults, or endurance athletes are unknown. Higher soreness doesn't mean better results—listen to your body.
medium confidenceWhy this study matters
Strength gains in just 2 weeks
Participants taking creatine (0.07 g/kg/day) showed significantly stronger performance in bench press, leg press, and shoulder press after only two weeks—before the placebo group caught up.
Most people think muscle gains take months, but this shows creatine can unlock noticeable strength in under 14 days—perfect for beginners or those prepping for a competition.
Creatine doesn't protect muscles—it makes them work harder
Contrary to popular belief, creatine didn't reduce muscle damage; instead, creatine users had significantly higher levels of creatine kinase (CK) and lactate dehydrogenase (LDH)—markers of muscle breakdown.
People take creatine thinking it's a recovery aid, but this study proves it’s a performance enhancer that pushes you to train harder—making soreness a sign of progress, not injury.
Not all exercises benefit equally
After 8 weeks, creatine boosted strength in bench press, leg press, shoulder press, and triceps extension—but had no significant effect on biceps curl or lat-pulldown.
This challenges the idea that creatine universally boosts all lifts—suggesting compound, multi-joint movements respond best, which could reshape workout routines.
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
Taking creatine while lifting weights helps you lift heavier faster, but it doesn't protect your muscles—it actually makes them more sore.
Research results
After 2 weeks, creatine users got stronger on 3 exercises; after 8 weeks, they got stronger on 4 exercises. Muscle damage markers were higher in creatine users than placebo users.
What this means - more context
Yes—getting stronger faster with more muscle soreness means creatine lets you train harder, which may help build more muscle over time.
To determine the time course of strength gains from creatine monohydrate supplementation during resistance training and whether it reduces muscle damage.
Creatine supplementation (0.07 g/kg/day) for 8 weeks during resistance training significantly increased strength in young males within 2 weeks for three exercises and in four exercises by week 8, but did not reduce muscle damage—instead, it elevated creatine kinase and lactate dehydrogenase levels compared to placebo.
Methods Used
Double-blind, randomized controlled trial with 18 young adult males (9 per group) receiving creatine monohydrate (0.07 g/kg/day) or placebo during 8 weeks of 3-day-per-week resistance training; strength measured across six exercises every 2 weeks; muscle damage assessed via serum creatine kinase and lactate dehydrogenase.
Main Finding
Creatine significantly increased strength after 2 weeks in bench press, leg press, and shoulder press; by week 8, significant gains persisted in those three plus triceps extension (but not biceps curl or lat-pulldown), while muscle damage markers were significantly higher in the creatine group than placebo.
Confidence Level
High—double-blind, randomized, controlled trial with direct measurements, clear statistical reporting (P<0.05), and appropriate sample size for a pilot study.
Study Flags
Red Flags
- •Small sample size (n=9 per group)
- •No effect sizes or confidence intervals reported
- •Only young males studied—limited generalizability
Surprising Findings
Creatine increased muscle damage markers (CK and LDH) instead of reducing them.
Most assume creatine reduces soreness or protects muscles; this study shows the opposite—higher damage markers suggest greater training intensity, not less recovery.
Practical Takeaways
Take 0.07g of creatine per kg of body weight daily during resistance training to boost strength gains in compound lifts like bench press and leg press.
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 553 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Human RCT
Subject
Moderate probability
on the GRADE evidence scale
This study showed that guys who took creatine while lifting weights got stronger faster than guys who took a fake pill. But it doesn't prove creatine works for everyone — just these 18 young men. It's like saying 'this snack helped these 5 kids run faster' — it might help others, but we don't know for sure.
No conflicts of interest were detected in this study. No score impact.
Strengths
- Randomized and double-blinded design
- Placebo-controlled group
- Pre-specified outcome measures (strength and biomarkers)
Weaknesses
- Very small sample size (n=9 per group)
- Limited demographic diversity (only young males)
- No power analysis reported
Methodology
Evidence Keywords
Statistical Reporting
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Taking creatine while lifting weights helps you lift heavier faster, but it doesn't protect your muscles—it actually makes them more sore.
Research results
After 2 weeks, creatine users got stronger on 3 exercises; after 8 weeks, they got stronger on 4 exercises. Muscle damage markers were higher in creatine users than placebo users.
What this means - more context
Yes—getting stronger faster with more muscle soreness means creatine lets you train harder, which may help build more muscle over time.
To determine the time course of strength gains from creatine monohydrate supplementation during resistance training and whether it reduces muscle damage.
Creatine supplementation (0.07 g/kg/day) for 8 weeks during resistance training significantly increased strength in young males within 2 weeks for three exercises and in four exercises by week 8, but did not reduce muscle damage—instead, it elevated creatine kinase and lactate dehydrogenase levels compared to placebo.
Methods Used
Double-blind, randomized controlled trial with 18 young adult males (9 per group) receiving creatine monohydrate (0.07 g/kg/day) or placebo during 8 weeks of 3-day-per-week resistance training; strength measured across six exercises every 2 weeks; muscle damage assessed via serum creatine kinase and lactate dehydrogenase.
Main Finding
Creatine significantly increased strength after 2 weeks in bench press, leg press, and shoulder press; by week 8, significant gains persisted in those three plus triceps extension (but not biceps curl or lat-pulldown), while muscle damage markers were significantly higher in the creatine group than placebo.
Confidence Level
High—double-blind, randomized, controlled trial with direct measurements, clear statistical reporting (P<0.05), and appropriate sample size for a pilot study.
Study Flags
Red Flags
- •Small sample size (n=9 per group)
- •No effect sizes or confidence intervals reported
- •Only young males studied—limited generalizability
Surprising Findings
Creatine increased muscle damage markers (CK and LDH) instead of reducing them.
Most assume creatine reduces soreness or protects muscles; this study shows the opposite—higher damage markers suggest greater training intensity, not less recovery.
Practical Takeaways
Take 0.07g of creatine per kg of body weight daily during resistance training to boost strength gains in compound lifts like bench press and leg press.
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 553 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Human RCT
Subject
Moderate probability
on the GRADE evidence scale
This study showed that guys who took creatine while lifting weights got stronger faster than guys who took a fake pill. But it doesn't prove creatine works for everyone — just these 18 young men. It's like saying 'this snack helped these 5 kids run faster' — it might help others, but we don't know for sure.
No conflicts of interest were detected in this study. No score impact.
Strengths
- Randomized and double-blinded design
- Placebo-controlled group
- Pre-specified outcome measures (strength and biomarkers)
Weaknesses
- Very small sample size (n=9 per group)
- Limited demographic diversity (only young males)
- No power analysis reported
Methodology
Evidence Keywords
Statistical Reporting
Scoring
How strong is this study?
This study did a good job by randomly giving some guys creatine and others a placebo, and nobody knew who got what — that makes it fair. But it only had 18 people, so if one person had a weird reaction, it could mess up the results. Bigger studies with more people would be more trustworthy.
0 / 100
- COI disclosureconflicts of interest not disclosed
- Data availabilitydata not shared
- Code availabilitycode not shared
77 / 100
- Randomization+20/20
- Blinding+15/15
- Control group+15/15
- Sample size (n=18)+1.7/20
- Follow-up+10/10
100 / 100
23 / 100
- P-values+15/15
- Effect sizeno effect size reported
- Confidence intervalsno confidence intervals
- 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 553 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
This design can establish causation. This is a randomized controlled trial with double blinding and a control group, which allows for causal inference between creatine supplementation and increased strength. However, the small sample size (n=18) and limited demographic (young males only) constrain the strength of generalizability and increase vulnerability to random error.
No Conflicts
No conflicts of interest identified
No conflicts of interest or funding statements were disclosed in the article; no industry ties or funder involvement are evident.
The article is openly accessible and appears to be independently conducted. No author affiliations suggest industry employment, and no funding sources are listed. However, absence of a COI or funding statement limits certainty; best practice would require explicit disclosure.
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 Dr Brad Stanfield cite this study, drawing 1 claim from it.
- Conflicting evidence
Evidence points in both directions — no clear conclusion yet.
Evidence
Authored by
3 researchersIf this is your work, this is how we attribute it on Fit Body Science. Mojtaba Kaviani is listed as the lead author.