Creatine

Findings:

Creatine monohydrate supplementation showed significant positive effects on memory function (SMD = 0.31), attention time (SMD = -0.31), and processing speed time (SMD = -0.51) in adults. No significant improvements were found for overall cognitive function or executive function. Subgroup analyses suggested greater benefits for attention time in individuals with diseases and those aged 18–60 years, and for processing speed time in females.

Participants:

The systematic review included 16 studies with a total of 492 adult participants aged 20.8–76.4 years. Participants included healthy individuals and patients with specific diseases (fibromyalgia, mild cognitive impairment associated with Parkinson’s disease, chronic schizophrenia). Studies included participants aged 18-59 years and ≥60 years, with some studies including only males, only females, or both.

Dosage:

All included studies used creatine monohydrate. Dosages varied across studies, including 3 g/day, 5 g/day, 10 g/day, 20 g/day, and 0.3 g/kg/day. Intervention durations ranged from 7 days to 18 months, categorized as short-term (<4 weeks) and long-term (≥4 weeks).

Study Quality Assessment:

Systematic review and meta-analysis following PRISMA 2020 guidelines, protocol registered with PROSPERO (CRD42024533557). Included studies were Randomized Controlled Trials (RCTs), including double-blind crossover RCTs and one pilot RCT, published between 1993 and 2024, retrieved from PubMed, Scopus, and Web of Science. Quality assessment used the Cochrane RoB 2.0 tool, finding low-to-moderate risk of bias overall. Publication bias was assessed using funnel plots and Egger's test (no significant bias detected). Sensitivity analyses were conducted. GRADE assessment rated certainty of evidence as moderate for memory, low for processing speed, and low to very low for overall cognitive function, executive function, and attention. Limitations acknowledged include heterogeneity in study design, sample size, and testing methods; relatively small sample sizes; limited evidence for specific populations.

All Effects:

Authors:

Darren G. Candow, Konstantinos Prokopidis, Kylie K. Harmon, Matt S. Stock, Scott C. Forbes, Sergej M. Ostojic

Findings:

Creatine supplementation can increase brain creatine stores, potentially benefiting cognition and memory, especially in aging adults or during metabolic stress like sleep deprivation. It also shows promise for improving outcomes in muscular dystrophy, traumatic brain injury (including concussions in children), depression, and anxiety. The review aims to summarize current research and discuss potential sex- and age-related differences.

Participants:

The review discusses research involving various populations, including 'aging adults', individuals during 'metabolic stress (i.e., sleep deprivation)', those with 'muscular dystrophy', 'traumatic brain injury (including concussions in children)', 'depression', and 'anxiety'. It also explores potential 'sex- or age-related differences'.

Study Quality Assessment:

The study is identified as a 'narrative review'. Multiple authors disclosed conflicts of interest, including industry-sponsored research, creatine donations, travel support, serving on scientific advisory boards for a creatine manufacturer (Alzchem), expert witness/consultant roles, and patents related to creatine.

All Effects:

Authors:

Bruno Gualano, Hamilton Roschel

Findings:

Creatine supplementation shows potential to improve cognitive processing, especially in conditions characterized by brain creatine deficits (induced by stressors or chronic conditions). However, the optimal protocol to increase brain creatine is yet to be determined, and further research assessing brain creatine and cognitive function concomitantly is warranted.

Participants:

Review focuses on effects in humans, particularly in conditions potentially characterized by brain creatine deficits (e.g., acute stressors like exercise/sleep deprivation, or chronic conditions like creatine synthesis enzyme deficiencies, mild traumatic brain injury, aging, Alzheimer's disease, depression).

Study Quality Assessment:

Identified as a Review article. Acknowledges that the optimal creatine protocol for brain effects is undetermined and more research combining brain creatine and cognitive function assessment is needed. Conflict of interest statement details potential funding/industry bias for multiple authors (connections to AlzChem, patents, industry funding).

All Effects:

Authors:

Konstantinos I Avgerinos

Findings:

Creatine monohydrate supplementation showed significant positive effects on memory, attention time, and information processing speed in adults. No significant improvements were found for overall cognitive function or executive function. Subgroup analyses suggested greater benefits in individuals with diseases, those aged 18–60 years, and females, with no significant difference between short- (<4 weeks) and long-term (≥4 weeks) interventions.

Participants:

The systematic review included 16 RCTs involving 492 participants aged 20.8–76.4 years. Participants included healthy individuals and patients with specific diseases (fibromyalgia, mild cognitive impairment associated with Parkinson’s disease, chronic schizophrenia). Three studies targeted older adults (≥60 years), thirteen focused on adults (18–59 years). Three studies included only females, three only males, and ten included both.

Dosage:

Creatine monohydrate was the form used in all 16 included studies. Intervention durations varied: nine studies lasted less than 4 weeks, and seven studies lasted 4 weeks or more. Specific dosages used across the included studies were not detailed in the provided text.

Study Quality Assessment:

Systematic review and meta-analysis following PRISMA 2020 guidelines, protocol registered on PROSPERO (CRD42024533557). Included 16 Randomized Controlled Trials (RCTs) published 1993-2024 (11 RCTs, 3 double-blind crossover RCTs, 1 pilot RCT). Quality assessed using Cochrane RoB 2.0 tool, finding low-to-moderate risk of bias overall. Publication bias assessed using funnel plots and Egger's test (no significant bias detected). GRADE assessment rated certainty of evidence as moderate for memory, low for processing speed, and low to very low for overall cognitive function, executive function, and attention. Acknowledged limitations include heterogeneity in study design/methods, small sample sizes, and focus primarily on healthy adults.

All Effects: