Endpoint
Muscle strength (pooled across mixed instruments)
The amount of force generated by muscle contraction. Muscle strength can be measured during isometric, isotonic, or isokinetic contraction, either manually or using a device such as a muscle strength dynamometer.
CAT:outcome/muscle-strength-pooledreported in standardised mean difference4 findings from 3 compounds
What moved it
How to read these marks4 findings · 3 compounds · 2 null · by evidence strength
| Compound | Direction | Findings | Strongest evidence |
|---|---|---|---|
| creatine | up 1 · no effect 1 | 2 | Evidence strength: very limited. Human evidence with major recorded weaknesses, or non-human, uncontrolled or unverified evidence. |
| caffeine | up | 1 | Evidence strength: very limited. Human evidence with major recorded weaknesses, or non-human, uncontrolled or unverified evidence. |
| melatonin | no effect | 1 | Evidence strength: very limited. Human evidence with major recorded weaknesses, or non-human, uncontrolled or unverified evidence. |
Reported to move it
2 findings
caffeine — increases
Very limitedEvidence strength: very limited. Human evidence with major recorded weaknesses, or non-human, uncontrolled or unverified evidence.Finding“An ergogenic effect of caffeinated chewing gum was found for muscular strength (SMD = 0.21; 95% confidence interval [CI]: 0.14-0.27).”
Quoted verbatim from Fast-Acting Caffeine: Does Caffeinated Chewing Gum Enhance Muscular Strength, Endurance, and Jumping Performance? A Systematic Review and Meta-Analysis.. - Study
- meta-analysis
- Population
- Caffeinated chewing gum versus placebo, gum consumed shortly before exercise; overall pooled estimate across the 21 included studies, pooling dynamic and isometric strength tests together rather than either test-type subgroup.
Fast-Acting Caffeine: Does Caffeinated Chewing Gum Enhance Muscular Strength, Endurance, and Jumping Performance? A Systematic Review and Meta-Analysis.2026PMID:42228847Permalink
creatine — increases
Very limitedEvidence strength: very limited. Human evidence with major recorded weaknesses, or non-human, uncontrolled or unverified evidence.Finding“Meta-analysis of six trials in muscular dystrophies including 192 participants revealed a significant increase in muscle strength in the creatine group compared to placebo, with a mean difference of 8.47%; (95% confidence intervals (CI) 3.55 to 13.38).”
Quoted verbatim from Creatine for treating muscle disorders.. - Study
- meta-analysis
- Participants
- 192
- Population
- Muscular dystrophy patients; meta-analysis of 6 trials
Effect 8.47 mean difference, 95% CI 3.55 to 13.38
Creatine for treating muscle disorders.2013PMID:23740606Permalink
Measured, no effect detected
2 findings
creatine — no detected effect on
Very limitedEvidence strength: very limited. Human evidence with major recorded weaknesses, or non-human, uncontrolled or unverified evidence.FindingNull result“Creatine supplementation did not alter muscle strength, muscle soreness, range of motion, or inflammation at each of the five follow-up times after exercise (<30 min, 24, 48, 72, and 96 hr; p > .05).”
Quoted verbatim from The Effect of Creatine Supplementation on Markers of Exercise-Induced Muscle Damage: A Systematic Review and Meta-Analysis of Human Intervention Trials.. - Study
- meta-analysis
- Population
- adults after exercise-induced muscle damage
The Effect of Creatine Supplementation on Markers of Exercise-Induced Muscle Damage: A Systematic Review and Meta-Analysis of Human Intervention Trials.2021PMID:33631721Permalink
melatonin — no detected effect on
Very limitedEvidence strength: very limited. Human evidence with major recorded weaknesses, or non-human, uncontrolled or unverified evidence.FindingNull result“Also, melatonin supplementation did not affect strength performance (0.19; 95% CI: -0.28 to 0.65).”
Quoted verbatim from Is melatonin as an ergogenic hormone a myth? a systematic review and meta-analysis.. - Study
- meta-analysis
- Population
- healthy subjects (athletes and exercise practitioners)
Is melatonin as an ergogenic hormone a myth? a systematic review and meta-analysis.2024PMID:37658244Permalink
How it is measured
Standardised mean difference or Hedges g for muscular strength, pooled across whatever strength tests the constituent trials happened to use, with no single test held constant across the pooled estimate.
Sources cited
4 papers
- Subject
- muscle strength (pooled across mixed instruments)
- Findings
- 4
- Papers
- 4
Fast-Acting Caffeine: Does Caffeinated Chewing Gum Enhance Muscular Strength, Endurance, and Jumping Performance? A Systematic Review and Meta-Analysis.record2026PMID:422288471 finding
Is melatonin as an ergogenic hormone a myth? a systematic review and meta-analysis.record2024PMID:376582441 finding
The Effect of Creatine Supplementation on Markers of Exercise-Induced Muscle Damage: A Systematic Review and Meta-Analysis of Human Intervention Trials.record2021PMID:336317211 finding
Creatine for treating muscle disorders.record2013PMID:237406061 finding