Alpha-GPC

Findings:

This paper provides a comprehensive guide on how to perform and write systematic reviews and meta-analyses, covering conceptual understanding, the importance of reporting guidelines (like PRISMA), and detailed methodological procedures from formulating a review question (PICO) to data analysis, presentation, and evidence assessment (GRADE). It highlights that systematic reviews and meta-analyses are crucial for verifying intervention effectiveness and informing evidence-based practice, but stresses that their quality and utility depend on rigorous execution to minimize bias, enhance transparency, and ensure reproducibility.

Study Quality Assessment:

The paper details methodologies for conducting high-quality systematic reviews and meta-analyses, emphasizing: adherence to reporting guidelines (e.g., PRISMA, CONSORT, STROBE, MOOSE, MECIR, EQUATOR Network); development and registration of a research protocol (e.g., PROSPERO, Cochrane); comprehensive literature search strategies (using PICO, MeSH, multiple databases like PubMed, EMBASE, Cochrane Central Register of Trials, CINAHL, and gray literature); explicit inclusion and exclusion criteria for literature selection (recommending inclusion of literature in all languages to mitigate selection bias); rigorous risk of bias assessment for individual studies (using tools like Cochrane's RoB, NOS, MINORS, QUADAS, RoB 2, ROBINS-I) and for the meta-analysis (e.g., funnel plots, Begg and Mazumdar test, Egger test); transparent data extraction and presentation (e.g., 'Characteristics of Included Studies' table); appropriate data analysis (qualitative synthesis or quantitative meta-analysis using fixed/random-effect models, addressing heterogeneity, and conducting sensitivity analysis); and assessment of the level of evidence (e.g., GRADE, AHRQ's Strength of Evidence, AMSTAR-2 for evaluating systematic reviews). The paper acknowledges concerns regarding the low quality and reproducibility of many existing systematic reviews and meta-analyses. Funding for this paper is disclosed: 'This study was supported by a National Research Foundation of Korea (NRF) grant funded by the Korean government (No. 2022R1A2C1012697)'.

All Effects:

Findings:

High dose (HD, 630mg) and low dose (LD, 315mg) A-GPC supplementation significantly increased cognitive performance in young, healthy males, as measured by statistically greater changes in Stroop total score compared to placebo. The HD group also showed significantly faster times to complete the Stroop test compared to placebo. No significant differences between groups were found for the Flanker and N-Back assessments, visual analog scales, physical performance, or growth hormone.

Participants:

20 resistance-trained males (31.3 ± 11.0 years, 178.6 ± 7.3 cm, 84.6 ± 11.4 kg, 15.4 ± 5.6% body fat)

Dosage:

Single doses of placebo (PL), 630 mg A-GPC (HD), or 315 mg A-GPC (LD) were consumed. Cognitive assessments were evaluated 60 minutes after ingestion.

Study Quality Assessment:

Randomized, double-blind, placebo-controlled, crossover approach. Sample size N=20. Cognitive assessments (Stroop, N-Back, Flanker), visual analog scales, and hemodynamic evaluations were performed. Venous blood was collected to evaluate changes in growth hormones. The study was retrospectively registered as NCT06690619 on clinicaltrials.gov. Conflict of interest statement: The author (CK) serves as a paid scientific advisor for the sponsor of this study (NNB Nutrition). A conflict-of-interest management plan was developed and followed by Lindenwood University, which required that the author was not involved in consenting of any human participants, data collection, or analysis of the data prior to unblinding. All data collection and statistical analysis was completed at the Center for Applied Health Sciences (Canfield, OH, USA).

Dosage:

low dose and high dose Alpha-GPC

Study Quality Assessment:

Randomized, three-arm, within-subject crossover

Findings:

Alpha-glycerylphosphorylcholine (αGPC) is a precursor of acetylcholine and can increase acetylcholine concentration in the brain. Clinical trials have been performed to evaluate the efficacy of αGPC for treating cognitive decline in patients with Alzheimer's.

Participants:

patients with Alzheimer's

Study Quality Assessment:

Clinical trials have been performed.