Creatine, Tissue Creatine, and Homocysteine: What GAA-Plus-Creatine Studies Have Actually Measured

This article explains the ingredient science behind Creatine Reserve™: what creatine does in the body, how the body makes it from its precursor guanidinoacetic acid, what a small number of human studies have measured when the two are combined, and how folate, vitamin B12, and vitamin B6 participate in homocysteine metabolism. It is written for readers who want the underlying science stated accurately, including its limits.

A note on scope before you read. The studies described below examined individual ingredients or ingredient blends that differ from this finished product in dose and form. They are included as background on the ingredients, not as evidence about Creatine Reserve™ itself, which has not been studied as a finished formula. Where a study measured a biomarker such as tissue creatine or plasma homocysteine, that is not the same as a health or cognitive outcome, and we have kept that distinction explicit throughout.

Quick answer: Creatine and guanidinoacetic acid (GAA) participate in the body’s creatine system. In two small human studies, GAA-plus-creatine blends were associated with changes in selected muscle and brain-region tissue-creatine measures. Those biomarker findings did not demonstrate a cognitive benefit, and they do not establish the effect of Creatine Reserve™, which has not been studied as a finished formula (Semeredi et al., 2019; Seper et al., 2021).

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

What Creatine Reserve™ Provides

Creatine Reserve™ is a powdered dietary supplement from Triquetra Health that combines creatine with its direct precursor, plus taurine and specified forms of folate, vitamin B12, and vitamin B6.

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Creatine and the Body’s Energy System

Cells run on adenosine triphosphate (ATP), and tissues that work in fast bursts need a way to regenerate ATP quickly. The phosphocreatine/creatine kinase system is that mechanism. Phosphocreatine acts as a rapidly available phosphate reserve that helps rebuild ATP at sites of high, fluctuating demand. This is the basic, well-established reason creatine matters in physiology.

The system is more elegant than a simple reserve tank. Creatine kinase, the enzyme that moves phosphate between creatine and ATP, exists as different isoforms positioned in different parts of the cell. One version sits near the mitochondria, where the bulk of ATP is generated, and another sits in the cytosol close to the structures that spend ATP. Phosphocreatine acts as a shuttle between the two, carrying high-energy phosphate from where it is made to where it is used, and buffering ATP levels so they stay steady when demand spikes. Researchers describe this as temporal and spatial energy buffering: it smooths out both the timing and the location of energy delivery (Bonilla et al., 2021). Tissues that work in sudden bursts, such as contracting muscle and neuronal electrical activity, are precisely the ones where that buffering earns its keep.

The brain is a notable high-demand tissue. It represents about 2% of body weight yet accounts for about 20% of the oxygen and calories the body consumes (Raichle & Gusnard, 2002). Most of the body’s creatine, however, is not in the brain. Approximately 95% of total body creatine is stored in skeletal muscle, with the remainder distributed across other tissues (Bonilla et al., 2021).

That distribution matters for anyone thinking about supplementation, because muscle and brain do not respond identically. Oral creatine raises muscle creatine reliably. The brain response is generally smaller and more variable between individuals, and it has differed across imaging studies (Forbes et al., 2022). The honest summary is that raising tissue creatine in muscle is well characterized, while the degree of change in the brain is less predictable and remains an area of active study.

How the Body Makes Creatine, and Where GAA Fits

The body synthesizes its own creatine in two steps. First, the enzyme AGAT (arginine:glycine amidinotransferase) combines the amino acids arginine and glycine to form guanidinoacetic acid, or GAA. Second, the enzyme GAMT (guanidinoacetate methyltransferase) adds a methyl group to GAA to produce creatine (Bonilla et al., 2021). GAA is therefore the body’s own direct precursor to creatine, one methylation step away from the finished molecule.

Because that final step consumes methyl groups, GAA intake interacts with the same methylation chemistry that handles homocysteine. In an eight-week trial, 55.6% of participants receiving 2.4 g/day GAA alone met the study’s hyperhomocysteinemia definition, whereas none of the participants receiving the same GAA dose together with betaine, folic acid, vitamin B12, and vitamin B6 did (Ostojic et al., 2013). A separate four-week study using 1 g/day GAA plus creatine did not find a total-homocysteine change (Semeredi et al., 2019). These differing small-study findings do not establish the effect of this finished formula. This formula includes folate, vitamin B12, and vitamin B6, and the interaction is described here at the level of general biochemistry, not as a statement about what Creatine Reserve™ does.

What the GAA-Plus-Creatine Studies Have Measured

Two small human studies have examined GAA-plus-creatine blends and measured tissue creatine. Both are worth reading precisely, with their designs and limits attached.

A Four-Week Study in Young Men

In a randomized, double-blind crossover trial, 14 healthy young men (mean age about 25) took either 1 g per day of GAA plus 3 g per day of creatine, or 4 g per day of creatine alone, for four weeks (Semeredi et al., 2019). In this small trial, the GAA-plus-creatine arm showed larger changes from baseline in midline occipital grey matter and vastus medialis creatine than the creatine-only arm.

These location-specific biomarker findings require replication. The white-matter measure was not statistically significant. The study did not measure memory, focus, or any cognitive outcome, and its 3 g creatine blend differs from the 5 g of creatine in this product. Total homocysteine did not change during either four-week arm of this small study; that finding does not establish the homocysteine effect of this finished formula.

An Eight-Week Pilot in Older Adults

A crossover pilot in 21 healthy older adults used 2 g per day of GAA plus 2 g per day of creatine (Seper et al., 2021). In this placebo-controlled crossover pilot, the blend was associated with higher creatine measures in individual brain regions of interest and vastus medialis on proton MRS versus placebo, while Montreal Cognitive Assessment (MoCA) and quality-of-life (SarQoL) scores did not differ between interventions. This research letter reports region-specific findings, and the text does not provide per-region effect sizes. The formulation differs from this product, and the meaningful takeaway is a measured tissue-creatine change, not a demonstrated cognitive effect.

Put together, these are small, short studies with location-specific imaging endpoints, and brain creatine responses to supplementation have varied across studies (Forbes et al., 2022). What can be said fairly is that combining GAA with creatine has, in limited data, raised certain tissue-creatine measures. What cannot be said is that this translates into a cognitive benefit, or that the finished formula reproduces these biomarker results. These small studies came from the same research group, and readers should note the authors’ disclosed industry advisory roles and creatine-related intellectual-property interests.

How Tissue Creatine Is Measured, and Why Brain Numbers Vary

The studies above measured creatine with magnetic resonance spectroscopy, or MRS, so it helps to understand what that technique can and cannot see. Proton MRS is a noninvasive method that reads the chemical signal from a small, defined block of tissue called a voxel. In typical in-vivo proton MRS, the creatine and phosphocreatine signals are visually unresolved, so what is commonly reported is combined total creatine, meaning creatine plus phosphocreatine (Hurd et al., 2026). In plain terms, MRS gives a pooled reading of the creatine system in one specific spot, not a separate tally of each molecule.

That design explains several of the caveats attached to the brain findings. Because the measurement is voxel-specific, a result taken in midline occipital grey matter does not automatically generalize to the whole brain, and two studies that place their voxels in different regions can reach different conclusions. Across studies, reported brain-creatine changes have been small and heterogeneous, and comparisons are complicated by different doses, study populations, brain regions, and MRS methods (Forbes et al., 2022). Small, short studies therefore need replication before broader conclusions are drawn.

This is why the accurate description of brain creatine supplementation is not “it does not work,” and equally not “it is proven.” It is more careful than either: the measured response is modest, region-dependent, variable between individuals, and still being characterized (Forbes et al., 2022). The GAA-plus-creatine studies discussed above sit inside those same limits, which is the honest frame for reading their percentages.

Homocysteine Metabolism and the B Vitamins

Homocysteine is an amino acid that sits at a junction of two metabolic pathways. In remethylation, homocysteine is converted back to methionine using folate and vitamin B12. In transsulfuration, it is routed toward cystathionine using vitamin B6. Folate status, vitamin B12 status, kidney function, certain medicines, and other factors can all affect a laboratory homocysteine result (McCaddon & Miller, 2023). This is standard biochemistry. This formula includes folate, vitamin B12, and vitamin B6, but the finished formula has not been studied for homocysteine outcomes.

It is worth walking through those two pathways a little more fully, because doing so explains why folate, B12, and B6 are usually discussed together, and how the topic connects to creatine at all.

In the remethylation pathway, homocysteine gets a methyl group added back and becomes methionine again. The main route uses the enzyme methionine synthase, which takes a methyl group from 5-methyltetrahydrofolate (the principal circulating form of folate) and requires vitamin B12 as a cofactor. A second remethylation route occurs in the liver and kidneys and uses betaine as the methyl donor. Because folate and B12 act on the same step, B12 status matters when interpreting folate, which is part of why the two are evaluated as a pair (McCaddon & Miller, 2023).

In the transsulfuration pathway, homocysteine takes a different exit. The enzyme cystathionine beta-synthase, which uses vitamin B6 as a cofactor, converts homocysteine to cystathionine, and from there the body can proceed toward cysteine and ultimately glutathione. This is the step that vitamin B6 supports (McCaddon & Miller, 2023).

The connection back to creatine runs through methionine. Once homocysteine is remethylated to methionine, methionine can be activated into S-adenosylmethionine, which serves as the body’s general-purpose methyl donor. That same methyl-donor pool is what the GAMT enzyme draws on when it converts guanidinoacetic acid into creatine (Bonilla et al., 2021; McCaddon & Miller, 2023). In other words, creatine synthesis and homocysteine metabolism share a common currency of methyl groups, which is the underlying reason the two subjects keep turning up side by side. Describing that shared chemistry is background on how the pathways are wired; it is not a statement about what this product does to anyone’s homocysteine.

A word on the MTHFR gene, because it is widely misunderstood. The common MTHFR C677T variant affects an enzyme that converts 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate, and it can influence folate metabolism. Its frequency varies across populations and ancestries (McCaddon & Miller, 2023; MedlinePlus Genetics, n.d.). Importantly, it is not, by itself, a reason to assume that a person cannot use ordinary folic acid. The U.S. Centers for Disease Control and Prevention states that people with common MTHFR variants can process folic acid, and that folic acid intake is more important than genotype for blood folate levels (CDC, n.d.). We mention this specifically to avoid the overstated genotype claims common in this category.

What the folate-form studies show, stated narrowly. In a 13-week trial of adults with moderate hyperhomocysteinemia, 200 mcg per day of 5-methyltetrahydrofolate, 200 mcg per day of folic acid, and a folate-rich diet each reduced homocysteine compared with placebo, and the reductions were broadly similar across the three approaches (Zappacosta et al., 2013).

In an earlier study using low equimolar doses (about 113 mcg of L-5-MTHF versus 100 mcg of folic acid) in healthy adults, L-5-MTHF was described by the authors as at least as effective as folic acid for homocysteine lowering (Venn et al., 2003), while another study at a higher dose level found no meaningful difference between the two forms (Lamers et al., 2004). None of these studies tested this finished formula, and taken together they do not establish that one folate form is clinically superior for the general consumer. L-5-MTHF is simply one folate form used in dietary supplements.

We are deliberately not framing homocysteine as a marker this product will change for you, and we are not directing readers to test and retest against it. If a healthcare professional has discussed homocysteine testing with you, that professional is the right person to advise whether and when repeat testing is appropriate, and whether a given supplement fits your situation.

Vitamin B6 Form and Safety

Pyridoxal-5-phosphate (P5P) is a phosphorylated coenzyme form of vitamin B6. Some mechanistic and cell-culture literature has examined how high concentrations of ordinary pyridoxine behave, and has discussed pyridoxine’s toxicity mechanisms (Vrolijk et al., 2017; Hadtstein & Vrolijk, 2021). That literature concerns pyridoxine and does not, on its own, establish that P5P products are better tolerated in people or that they remove vitamin B6 safety considerations.

Vitamin B6 does have a recognized safety endpoint: long-term high supplemental intake can cause peripheral neuropathy. The U.S. Food and Nutrition Board’s adult tolerable upper intake level for vitamin B6 is 100 mg/day from combined food and supplement intake, and NIH ODS notes that EFSA set a 12 mg/day upper level for adults in 2023 (NIH Office of Dietary Supplements, n.d.). Verify the vitamin B6 amount declared on the final Supplement Facts panel and consider your total supplemental intake.

Taurine

Taurine is an amino sulfonic acid found in many tissues throughout the body and widely used in dietary supplements. This formula provides 1,500 mg. We are not attaching a cardiovascular, blood-pressure, or brain claim to it here. In the animal data reviewed in the European Food Safety Authority’s 2009 opinion, 14 days of oral taurine did not increase total brain taurine in rats; this animal finding is not a human brain-effect claim (EFSA, 2009).

Why These Ingredients Are Together

Creatine Reserve™ pairs finished creatine with guanidinoacetic acid, or GAA, the direct compound the body converts into creatine. It also includes taurine, folate, vitamin B12, and vitamin B6.

In the body’s natural creatine-making pathway, GAA is converted into creatine through a methylation step. Folate, vitamin B12, and vitamin B6 participate in normal pathways involving homocysteine and methyl-group metabolism, which is why these ingredients are often discussed together. (Bonilla et al., 2021; McCaddon & Miller, 2023)

Put simply, the formula combines finished creatine with its direct precursor and B vitamins that have related roles in normal metabolism. This explains the ingredient combination. It is not a claim that the product will change homocysteine, increase brain creatine, or produce a cognitive or health outcome for any individual.

Small studies of GAA-plus-creatine blends have measured changes in certain tissue-creatine signals, but they used different formulas, doses, and participants than Creatine Reserve™. Those studies did not test this finished formula or establish a cognitive benefit. (Semeredi et al., 2019)

Creatine Reserve™ has not been studied as a finished formula. The research in this article is included to explain the ingredients and the underlying pathways, not to suggest that results from separate studies apply directly to this product.

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Creatine and Kidney Function

Creatine is among the most-studied dietary supplement ingredients. A 2025 systematic review and meta-analysis found no statistically significant pooled difference in glomerular filtration rate (a measure of kidney filtration) with creatine supplementation, alongside a modest rise in serum creatinine that the authors considered likely related to creatine metabolism (Kabiri Naeini et al., 2025). Serum creatinine is itself a downstream metabolite of creatine, so this modest change occurred without a statistically significant pooled GFR difference; clinicians should interpret kidney tests in the full clinical context. The studies in that review were generally small and included mixed populations. Anyone with existing kidney disease should discuss creatine with their healthcare professional.

Who Might Consider It, and Sensible Use

Creatine Reserve™ may be of interest if you already take or plan to take creatine and prefer a formula that also includes GAA, taurine, folate, vitamin B12, and vitamin B6. If a healthcare professional has discussed homocysteine testing or B-vitamin status with you, ask that professional whether this product is appropriate for you rather than using it to self-manage a laboratory result.

Use only as directed on the product label. Do not use this product to self-manage an abnormal laboratory value. Consult a healthcare professional before use if you are pregnant or nursing, have a medical condition, or take prescription medication.

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Frequently Asked Questions

What is guanidinoacetic acid, and why is it in a creatine product?

GAA is the molecule your own body makes and then converts into creatine, using a single methylation step performed by the GAMT enzyme (Bonilla et al., 2021). Including it supplies the direct precursor alongside finished creatine. In a small four-week study in young men, a GAA-plus-creatine blend produced larger changes in certain tissue-creatine measures than creatine alone (Semeredi et al., 2019), though that was a biomarker study in a different formulation, not a test of this product, and it did not measure cognition.

Does combining GAA with creatine raise brain creatine?

Two small human studies reported increases in certain brain-region creatine measures on magnetic resonance spectroscopy with GAA-plus-creatine blends (Semeredi et al., 2019; Seper et al., 2021). Both were small, used formulations different from this product, and did not demonstrate a cognitive effect; in the older-adult pilot, the cognitive test difference was not statistically significant (Seper et al., 2021). Brain creatine responses to supplementation vary across individuals and studies (Forbes et al., 2022).

What does the MTHFR gene variant mean for folate?

The common MTHFR C677T variant can influence folate metabolism, and its frequency differs across populations. It does not mean a person cannot use ordinary folic acid; the CDC notes that people with common MTHFR variants can process folic acid and that folic acid intake matters more than genotype for blood folate (CDC, n.d.). L-5-methyltetrahydrofolate is one folate form used in supplements. Studies comparing it with folic acid have generally found similar homocysteine effects (Zappacosta et al., 2013; Lamers et al., 2004).

Why does the formula use pyridoxal-5-phosphate?

P5P is a coenzyme form of vitamin B6. The choice of form is a formulation decision. Because vitamin B6 safety guidance concerns total vitamin B6 intake, consider your combined intake from all supplements and follow the verified product label.

Is creatine hard on the kidneys?

A 2025 meta-analysis found no statistically significant pooled GFR difference with creatine, alongside a modest rise in serum creatinine that the authors considered likely related to creatine metabolism (Kabiri Naeini et al., 2025). People with kidney disease should consult their healthcare professional before use.

Scientific References & Citations

Sources are listed for the scientific claims discussed in this article. The studies referenced here examined individual ingredients or different GAA, creatine, and B-vitamin protocols. Creatine Reserve™ as a finished formula has not been studied, and we do not claim that it reproduces the biomarker results seen in those separate studies.

Bonilla, D. A., Kreider, R. B., Stout, J. R., Forero, D. A., Kerksick, C. M., Roberts, M. D., & Rawson, E. S. (2021). Metabolic basis of creatine in health and disease: A bioinformatics-assisted review. Nutrients, 13(4), 1238. https://doi.org/10.3390/nu13041238

Centers for Disease Control and Prevention. (n.d.). MTHFR gene variant and folic acid facts. U.S. Department of Health and Human Services. https://www.cdc.gov/folic-acid/data-research/mthfr/index.html

European Food Safety Authority Panel on Food Additives and Nutrient Sources Added to Food. (2009). The use of taurine and D-glucurono-gamma-lactone as constituents of the so-called “energy” drinks. EFSA Journal, 7(2), 935. https://doi.org/10.2903/j.efsa.2009.935

Forbes, S. C., Cordingley, D. M., Cornish, S. M., Gualano, B., Roschel, H., Ostojic, S. M., Rawson, E. S., Roy, B. D., Prokopidis, K., Giannos, P., & Candow, D. G. (2022). Effects of creatine supplementation on brain function and health. Nutrients, 14(5), 921. https://doi.org/10.3390/nu14050921

Hadtstein, F., & Vrolijk, M. (2021). Vitamin B-6-induced neuropathy: Exploring the mechanisms of pyridoxine toxicity. Advances in Nutrition, 12(5), 1911–1929. https://doi.org/10.1093/advances/nmab033

Hurd, R. E., Gu, M., Adamson, P. M., Okamura, K., Shibata, M., Ono, Y., Haidar, M., Riemer, K., Hanley, F. L., & Spielman, D. M. (2026). Differentiating creatine and phosphocreatine in vivo using 3 T 1H MR spectroscopy. Magnetic Resonance in Medicine, 95(4), 1896–1906. https://doi.org/10.1002/mrm.70171

Kabiri Naeini, E., Eskandari, M., Mortazavi, M., Gholaminejad, A., & Karevan, N. (2025). Effect of creatine supplementation on kidney function: A systematic review and meta-analysis. BMC Nephrology, 26, 622. https://doi.org/10.1186/s12882-025-04558-6

Lamers, Y., Prinz-Langenohl, R., Moser, R., & Pietrzik, K. (2004). Supplementation with [6S]-5-methyltetrahydrofolate or folic acid equally reduces plasma total homocysteine concentrations in healthy women. The American Journal of Clinical Nutrition, 79(3), 473–478. https://doi.org/10.1093/ajcn/79.3.473

McCaddon, A., & Miller, J. W. (2023). Homocysteine: A retrospective and prospective appraisal. Frontiers in Nutrition, 10, Article 1179807. https://doi.org/10.3389/fnut.2023.1179807

MedlinePlus Genetics. (n.d.). MTHFR gene. U.S. National Library of Medicine. https://medlineplus.gov/genetics/gene/mthfr/

National Institutes of Health, Office of Dietary Supplements. (n.d.). Vitamin B6: Fact sheet for health professionals. https://ods.od.nih.gov/factsheets/VitaminB6-HealthProfessional/

Ostojic, S. M., Niess, B., Stojanovic, M., & Obrenovic, M. (2013). Co-administration of methyl donors along with guanidinoacetic acid reduces the incidence of hyperhomocysteinaemia compared with guanidinoacetic acid administration alone. British Journal of Nutrition, 110(5), 865–870. https://doi.org/10.1017/S0007114512005879

Raichle, M. E., & Gusnard, D. A. (2002). Appraising the brain’s energy budget. Proceedings of the National Academy of Sciences, 99(16), 10237–10239. https://doi.org/10.1073/pnas.172399499

Semeredi, S., Stajer, V., Ostojic, J., Vranes, M., & Ostojic, S. M. (2019). Guanidinoacetic acid with creatine compared with creatine alone for tissue creatine content, hyperhomocysteinemia, and exercise performance: A randomized, double-blind superiority trial. Nutrition, 57, 162–166. https://doi.org/10.1016/j.nut.2018.04.009

Seper, V., Korovljev, D., Todorovic, N., Stajer, V., Ostojic, J., Nesic, N., & Ostojic, S. M. (2021). Guanidinoacetate-creatine supplementation improves functional performance and muscle and brain bioenergetics in the elderly: A pilot study. Annals of Nutrition and Metabolism, 77(4), 244–247. https://doi.org/10.1159/000518499

Venn, B. J., Green, T. J., Moser, R., & Mann, J. I. (2003). Comparison of the effect of low-dose supplementation with L-5-methyltetrahydrofolate or folic acid on plasma homocysteine: A randomized placebo-controlled study. The American Journal of Clinical Nutrition, 77(3), 658–662. https://doi.org/10.1093/ajcn/77.3.658

Vrolijk, M. F., Opperhuizen, A., Jansen, E. H. J. M., Hageman, G. J., Bast, A., & Haenen, G. R. M. M. (2017). The vitamin B6 paradox: Supplementation with high concentrations of pyridoxine leads to decreased vitamin B6 function. Toxicology in Vitro, 44, 206–212. https://doi.org/10.1016/j.tiv.2017.07.009

Zappacosta, B., Mastroiacovo, P., Persichilli, S., Pounis, G., Ruggeri, S., Minucci, A., Carnovale, E., Andria, G., Ricci, R., Scala, I., Genovese, O., Turrini, A., Mistura, L., Giardina, B., & Iacoviello, L. (2013). Homocysteine lowering by folate-rich diet or pharmacological supplementations in subjects with moderate hyperhomocysteinemia. Nutrients, 5(5), 1531–1543. https://doi.org/10.3390/nu5051531

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. This article is general information about the ingredients and is not medical advice. Consult a healthcare professional before beginning any new supplement, particularly if you are pregnant or nursing, have a medical condition, or take prescription medication.