Endpoint

Upper-body muscular strength (pooled composite)

CAT:outcome/upper-body-strength-compositereported in standardised mean difference (SMD)5 findings from 2 compounds

What moved it

5 findings · 2 compounds · by evidence strength

Compound	Direction	Findings	Strongest evidence
creatine	up	3	Evidence strength: moderate. Human evidence with one recorded weakness, or capped at moderate by its design or by unread numbers.
caffeine	up	2	Evidence strength: moderate. Human evidence with one recorded weakness, or capped at moderate by its design or by unread numbers.

Reported to move it

5 findings

creatine — increases
ModerateEvidence strength: moderate. Human evidence with one recorded weakness, or capped at moderate by its design or by unread numbers.Findingreplicated ×2
“Overall, Cr significantly increased measures of upper-body strength (7 studies, n = 142, p = 0.04), with no effect on lower-body strength or measures of muscle mass.”
Quoted verbatim from Efficacy of Creatine Supplementation Combined with Resistance Training on Muscle Strength and Muscle Mass in Older Females: A Systematic Review and Meta-Analysis..
Study

meta-analysis
Participants

142
Population

Older females performing resistance training
Efficacy of Creatine Supplementation Combined with Resistance Training on Muscle Strength and Muscle Mass in Older Females: A Systematic Review and Meta-Analysis.2021PMID:34836013Permalink
caffeine — increases
ModerateEvidence strength: moderate. Human evidence with one recorded weakness, or capped at moderate by its design or by unread numbers.Findingreplicated ×1
“A subgroup analysis indicated that caffeine significantly improves upper (SMD = 0.21; 95% CI: 0.02, 0.39; p = 0.026; Fig. 3) but not lower body strength (SMD = 0.15; 95% CI: -0.05, 0.34; p = 0.147; Fig. 4).”
Quoted verbatim from Effects of caffeine intake on muscle strength and power: a systematic review and meta-analysis..
Study

meta-analysis
Dose

Acute pre-exercise ingestion (capsule, liquid or gel), mean 4.7 mg/kg, range 0.9-6 mg/kg, 45-60 min before testing
Population

Healthy adolescent and young-adult participants, trained and untrained, of both sexes; UPPER-BODY SUBGROUP of the pooled 1RM maximal-strength analysis, not the overall estimate. Constituent tests: bench press, machine bench press, lat pulldown.
Effect 0.21 standardised mean difference, 95% CI 0.02 to 0.39
Effects of caffeine intake on muscle strength and power: a systematic review and meta-analysis.2018PMID:29527137Permalink
caffeine — increases
ModerateEvidence strength: moderate. Human evidence with one recorded weakness, or capped at moderate by its design or by unread numbers.Findingreplicated ×1
“In a subgroup analysis that considered only upper-body 1RM tests, there was a significant ergogenic effect of caffeine (SMD: 0.17; 95% CI: 0.09, 0.26; p < 0.001; I2 = 0%).”
Quoted verbatim from Ergogenic Effects of Acute Caffeine Intake on Muscular Endurance and Muscular Strength in Women: A Meta-Analysis..
Study

meta-analysis
Population

Healthy adult women; subgroup analysis restricted to upper-body 1RM tests (bench press, bicep curl, lat pull-down, shoulder press, row), not the overall estimate
Effect 0.17 standardised mean difference, 95% CI 0.09 to 0.26
Ergogenic Effects of Acute Caffeine Intake on Muscular Endurance and Muscular Strength in Women: A Meta-Analysis.2021PMID:34072182Permalink
creatine — increases
ModerateEvidence strength: moderate. Human evidence with one recorded weakness, or capped at moderate by its design or by unread numbers.Findingreplicated ×2
“In comparison with a placebo, creatine supplementation combined with resistance training significantly increased upper-body (WMD = 4.43 kg, p < 0.001) and lower-body strength (WMD = 11.35 kg, p < 0.001).”
Quoted verbatim from Effects of Creatine Supplementation and Resistance Training on Muscle Strength Gains in Adults <50 Years of Age: A Systematic Review and Meta-Analysis..
Study

meta-analysis
Population

adults <50 years of age undertaking resistance training
Effects of Creatine Supplementation and Resistance Training on Muscle Strength Gains in Adults <50 Years of Age: A Systematic Review and Meta-Analysis.2024PMID:39519498An author is affiliated with a producerPermalink
creatine — increases
Very limitedEvidence strength: very limited. Human evidence with major recorded weaknesses, or non-human, uncontrolled or unverified evidence.Findingreplicated ×2
“Compared with resistance training alone (RT), resistance training plus creatine (RT + CR) produced significant increases in upper-body strength (g = 0.54, p < 0.001), lower-body strength (g = 0.55, p < 0.001), lean mass (g = 0.30, p < 0.001), and body mass (g = 0.12, p = 0.04), and a significant reduction in body-fat percentage (g = -0.14, p = 0.02).”
Quoted verbatim from Resistance training combined with creatine supplementation: a three-level meta-analysis of multidimensional outcomes from strength enhancement to body composition remodeling..
Study

meta-analysis
Population

Resistance-trained adults; three-level meta-analysis of 63 RCTs (n = 1489); resistance training given to both arms
Effect 0.54 standardised mean difference
Resistance training combined with creatine supplementation: a three-level meta-analysis of multidimensional outcomes from strength enhancement to body composition remodeling.2026PMID:42765482Permalink

How it is measured

Meta-analytic aggregate of upper-body strength across whichever tests the primary trials used — chest press, bench press, elbow flexion, lat pulldown — reported as a standardised mean difference, or in kilograms where the review pooled a common test. The constituent tests are listed with each finding, as is whether handgrip was folded in.

Sources cited

5 papers

Subject: upper-body muscular strength (pooled composite)
Findings: 5
Papers: 5

Compound

Direction

Findings

Strongest evidence

creatine

caffeine

How it is measured