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Exploring the Cognitive Effects of Guanidinoacetic Acid (GAA) and Creatine

By the CreatineIQ Research Desk
Last reviewed
New Research
Brain Health

Brain energy metabolism is a growing frontier in sports nutrition, with researchers continually exploring ways to increase brain creatine levels more effectively. While standard creatine monohydrate struggles to cross the blood-brain barrier efficiently, guanidinoacetic acid (GAA)1—a direct precursor to creatine—has emerged as a potential alternative. Previous research suggests GAA might elevate brain creatine content more effectively than creatine alone.

This exploratory clinical trial investigated whether supplementing with GAA, either on its own or stacked with creatine monohydrate, could translate these theoretical brain-metabolism advantages into measurable improvements in cognitive function, mood, and overall health.

Key Takeaways

  • GAA with and without creatine: The trial tested guanidinoacetic acid (GAA) alone and combined with standard creatine monohydrate over six weeks.
  • Marginal cognitive benefits: While some improvements were noted in delayed verbal memory and specific reaction times, the vast majority of cognitive tests showed no significant change.
  • Mixed secondary outcomes: The GAA group differed significantly from placebo on one perceived-stress item and in self-reported moderate physical activity, while changes in vitality and other quality-of-life items only approached significance, alongside some potentially undesirable shifts in sleep quality.
  • Trivial clinical impact: The significant cognitive results are confined to a handful of reaction-time measures inside a large test battery, with much of the rest only approaching significance — a pattern that points to minimal real-world impact.

The Study Design

This proof-of-concept, double-blind randomized controlled trial involved 58 healthy, active adults (33 females; average age 35.5 ± 14 years; 76.2 ± 14 kg). Participants were assigned to one of three groups for six weeks:

  • Placebo (PLA): 12g per day of maltodextrin (split into two doses).
  • GAA: 2g per day of GAA plus 10g of a placebo.
  • GAA + CrM: 2g per day of GAA combined with 10g per day of creatine monohydrate.

At baseline and after six weeks, participants provided fasting blood samples and completed an extensive battery of assessments. These included cognitive performance tests (reaction time, Stroop Color-Word Task, Corsi Block Task, among others), as well as questionnaires evaluating mood, perceived stress, and sleep quality.

The Findings

The primary cognitive findings were generally underwhelming, though not uniformly so. GAA supplementation only "tended" to improve overall reaction time against placebo (-241.8 ms, p = 0.10). Two reaction-time results did reach significance, however: the interaction effect on overall reaction time (-330 ms, p = 0.031) and on "YES" reaction time (-290 ms, p = 0.004). Others merely approached it — recalled correct reaction time (p = 0.078) and recalled correct "YES" responses (p = 0.084) both landed in the 0.05-to-0.10 band that the authors report as "approaching significance" rather than as a significant p-value2. In the authors' own conclusion, both the GAA and the GAA + CrM protocols improved delayed verbal episodic recognition memory and retrieval speed.

However, the authors report limited to no effects on the Delayed Picture Recognition Task, Digit Vigilance Task, Corsi Block Task, or Stroop Color-Word Task.

Secondary markers were similarly mixed. On the Perceived Stress Scale, the GAA group reported "a lower frequency of controlling irritations" (p = 0.036), plus a borderline result for "feeling like difficulties are mounting" (p = 0.053). That same group reported feeling worn out less often (p = 0.068) and rating their health as excellent more often (p = 0.092). The combined GAA + CrM group reported feeling "full of life" more often (p = 0.081) and feeling downhearted and depressed less often (p = 0.066), but also reported more frequent limitations when bending, kneeling, or stooping (p = 0.053). Sleep quality assessments revealed a mix of positive and potentially undesirable effects. No clinically meaningful changes were observed in blood markers or in self-reported side effects in any group.

Analyzing the Study: Strengths & Limitations

Strengths and Reputability

The trial utilized a robust double-blind, randomized, and counterbalanced design, and it carries a clinical trial registration (ISRCTN68542582). That registration is weaker than it looks, though: according to the full text it was submitted in November 2025, ten months after ethics approval in January 2025, and the paper does not say when enrolment began, so there is no evidence it preceded data collection. It is not relied on here as a safeguard against outcome-switching.

Limitations

The study's primary limitation is how much of it rests on marginal findings: the abstract reports a whole tier of results that merely "approached significance" alongside the genuinely significant ones, and reading that tier as signal is what makes the overall picture look stronger than it is. The registration does less work here than it might, too — this is explicitly a proof-of-concept exploratory trial, and even the full text defines its primary outcome only as "cognitive function" across the whole battery of tests, so there is no single pre-specified result against which the rest can be judged. When a battery that large is administered and only a handful of measures yield significant results, the likelihood of false positives climbs.

One further confound goes unaddressed. Participants in the GAA group spent significantly more time in moderate physical activity than the placebo group (p < 0.05). Exercise independently affects cognition, mood, and sleep — the very outcomes in question — so the group differences reported here cannot be cleanly attributed to the supplement.

Conflicts of Interest

PubMed does carry a conflict-of-interest statement for this record, and it bears directly on the interventions tested. Senior author R.B. Kreider serves as a paid consultant to, and Chair of the Scientific Advisory Board for, AlzChem Trostberg GmbH — the company that manufactures both creatine monohydrate and GAA. He also sits on the Scientific Advisory Board of Trace Minerals, which sells neither compound, and declares no financial stake (patents, royalties, or stock) in any supplement company; his consulting roles are reviewed and approved by Texas A&M University, and the lab uses an external quality-assurance reviewer. The study was funded by the WoodNext Foundation, which sells no nutrition or creatine products. According to the full text, AlzChem also donated the supplements used in the study — both the creatine monohydrate and the GAA are AlzChem products — and funded the homocysteine assays; the paper states that the sponsors had no role in the study design, data collection, analysis, interpretation or manuscript. The authors declare no conflicts of interest. None of this invalidates the results, but an advisory relationship with the manufacturer of both compounds under test, which also supplied them, is context worth weighing.

Conclusion

This study earned a weighted rubric score of 3.50 out of 5.00. Raising brain creatine by way of its precursor is a genuinely interesting route — GAA is thought to cross the blood-brain barrier more readily than creatine monohydrate does, rather than to bypass it. Pairing that precursor with creatine is not new: a 2019 trial by Semeredi and colleagues (reference 2) compared a GAA-creatine mixture with creatine alone for tissue creatine and exercise performance, and the paper itself cites small earlier studies of the combination on brain oxygenation during a cognitive task and on esports performance. What this trial adds is a six-week test against a broad cognitive and health battery. However, this proof-of-concept trial delivers an incremental and largely equivocal result. Because the significant cognitive findings are confined to a few reaction-time measures within a large battery and sit beside a whole tier of results that only approached significance, the clinical significance of these improvements is likely trivial.

While GAA remains a compound worth watching in sports nutrition, this study does not provide sufficient evidence to recommend adding GAA to a standard cognitive or brain-health supplementation protocol. Further research with larger sample sizes and more targeted cognitive primary endpoints is required.

References

  1. Chun J, Babakhani K, Gonzalez DE, et al. Effects of six weeks of guanidinoacetic acid supplementation with and without creatine monohydrate on cognitive function and markers of health in healthy adults. Journal of the International Society of Sports Nutrition. 10.1080/15502783.2026.2711032
  2. Semeredi S, Stajer V, Ostojic J, Vranes M, Ostojic SM. Guanidinoacetic acid with creatine compared with creatine alone for tissue creatine content, hyperhomocysteinemia, and exercise performance: a randomized, double-blind superiority trial. Nutrition. 2019;57:162-166. PubMed 30170305

Glossary

  1. Guanidinoacetic acid (GAA): An amino acid derivative and the direct, immediate metabolic precursor to creatine in the human body. ↩

  2. P-value: A statistical measurement that indicates the probability of obtaining the observed results assuming that the null hypothesis is true. A lower p-value indicates stronger evidence for an effect. ↩