Interaction Between Caffeine and Creatine When Used as Concurrent Ergogenic Supplements: A Systematic Review.
Level 1 - systematic review of randomized trials
Systematic review of intervention trials
PubMed 35016154 · doi:10.1123/ijsnem.2021-0262
What was done
A systematic review following PRISMA guidelines searched PubMed, Web of Science, MEDLINE, CINAHL, and SPORTDiscus through November 2021 to examine performance interactions between creatine and caffeine supplementation. Ten studies evaluating acute and chronic concurrent supplementation protocols were included.
What was found
The abstract reports no numerical values, effect estimates, or confidence intervals. Across the 10 included studies: for creatine loading followed by an acute pre-exercise caffeine dose, three studies found no interference with caffeine's benefits, while one found acute caffeine alone was beneficial but acute combined supplementation was not. For chronic concurrent supplementation, two studies found caffeine interfered with creatine benefits, three found no interaction, and one found synergy.
Why it matters
This review synthesizes the conflicting literature on combining two common ergogenic aids, suggesting that acute caffeine use following creatine loading is generally viable, whereas chronic daily co-ingestion may compromise creatine's effectiveness.
Limits
The abstract provides no total participant count, effect sizes, or meta-analytic pooling. The underlying evidence base is small (10 studies) and presents conflicting results for chronic co-ingestion. Details on specific dosages, timing protocols, participant training status, and measured exercise modalities are absent from the abstract.
Cited by
- partial Caffeine doses exceeding 250 mg cause an interference effect with creatine at the cellular level by opposing calcium release and uptake kinetics in the sarcoplasmic reticulum, increasing muscle relaxation time.