What are the main creatine formulations and variants?

    Last Updated: November 20, 2023

    Creatine monohydrate is the most common form of creatine, and, unless otherwise stated, the default form of creatine used in most studies.[1] It has high intestinal absorption, with bioavailability of approximately 99% at standard doses of 5–10 g.[2][3] That said, there is evidence to suggest that high acute doses (greater than 10g) of creatine monohydrate can saturate intestinal uptake, lowering absorption and increasing fecal secretion.[4]

    This basic form of creatine comes in two variants: creatine anhydrous and micronized creatine monohydrate.

    Creatine anhydrous (anhydrous coming from the Greek “an-” meaning “without”, and “hydor” meaning “water”) is just creatine without the monohydrate. Creatine anhydrous is converted to creatine monohydrate when exposed to water.[5][6] Because it does not contain monohydrate, creatine anhydrous is 100% creatine by weight, whereas creatine monohydrate is 88% creatine and 12% monohydrate by weight.

    Micronized creatine monohydrate is creatine monohydrate that undergoes a mechanical process that reduces the particle size and increases the water solubility of creatine.

    Other creatine formulations include:

    • Creatine hydrochloride (Creatine HCl): This form is characterized by the creatine molecules being bound with hydrochloric acid. Creatine HCl is touted to require a lower dosage. However, this claim has not been scientifically proven and seems unlikely, since the stomach has an abundance of HCl anyway, and creatine will separate from HCl in the stomach. Thus, both creatine HCl and creatine monohydrate form free creatine in the stomach.
    • Liquid creatine: This form has been found to be less effective than creatine monohydrate.[7] The reduced effect is likely due to the passive breakdown of creatine over a period of days into creatinine, which occurs when creatine is suspended in solution.[8] This is not an issue for people preparing a creatine solution at home, since it takes a few days for creatine to start degrading into creatinine.
    • Buffered creatine (Kre-Alkalyn): This form of creatine has a higher pH level than creatine monohydrate. This is accomplished by adding alkaline powder to creatine. Buffered creatine is touted to enhance the effects of creatine monohydrate. However, this claim has not been scientifically proven. In fact, a 2012 study comparing buffered creatine to creatine monohydrate in 36 resistance-trained individuals found no significant differences between the two with regard to the accumulation of creatine in muscle tissue, training adaptations, or adverse effects.[9]
    • Creatine ethyl ester: This is an esterified form of creatine monohydrate that has been found to be less effective than creatine monohydrate for increasing muscle creatine levels and enhancing resistance training adaptations.[10]
    • Magnesium-chelated creatine: In this form of creatine, magnesium ions are attached to the creatine molecules. Limited research suggests that this form of creatine may have the same ergogenic effects as creatine monohydrate.[11]
    • Creatine nitrate: In this form of creatine, a nitrate (NO3−) ion is attached to a creatine molecule. Despite creatine nitrate being more soluble in water, it doesn't appear to enhance athletic performance more than creatine monohydrate.[12]

    References

    1. ^Dash AK, Mo Y, Pyne ASolid-state properties of creatine monohydrate.J Pharm Sci.(2002-Mar)
    2. ^Jäger R, Purpura M, Shao A, Inoue T, Kreider RBAnalysis of the efficacy, safety, and regulatory status of novel forms of creatine.Amino Acids.(2011-May)
    3. ^Jäger R, Harris RC, Purpura M, Francaux MComparison of new forms of creatine in raising plasma creatine levels.J Int Soc Sports Nutr.(2007-Nov-12)
    4. ^McCall W, Persky AMPharmacokinetics of creatineSubcell Biochem.(2007)
    5. ^Yukoh Sakata, Sumihiro Shiraishi, Makoto OtsukaEffect of pulverization on hydration kinetic behaviors of creatine anhydrate powdersColloids Surf B Biointerfaces.(2004 Dec 25)
    6. ^Sakata Y, Shiraishi S, Otsuka MEffect of pulverization of the bulk powder on the hydration of creatine anhydrate tablets and their pharmaceutical properties.Colloids Surf B Biointerfaces.(2005-Dec-10)
    7. ^Astorino TA, Marrocco AC, Gross SM, Johnson DL, Brazil CM, Icenhower ME, Kneessi RJIs running performance enhanced with creatine serum ingestion?J Strength Cond Res.(2005-Nov)
    8. ^Gill ND, Hall RD, Blazevich AJCreatine serum is not as effective as creatine powder for improving cycle sprint performance in competitive male team-sport athletes.J Strength Cond Res.(2004-May)
    9. ^Jagim AR, Oliver JM, Sanchez A, Galvan E, Fluckey J, Riechman S, Greenwood M, Kelly K, Meininger C, Rasmussen C, Kreider RBA buffered form of creatine does not promote greater changes in muscle creatine content, body composition, or training adaptations than creatine monohydrate.J Int Soc Sports Nutr.(2012-Sep-13)
    10. ^Spillane M, Schoch R, Cooke M, Harvey T, Greenwood M, Kreider R, Willoughby DSThe effects of creatine ethyl ester supplementation combined with heavy resistance training on body composition, muscle performance, and serum and muscle creatine levelsJ Int Soc Sports Nutr.(2009 Feb 19)
    11. ^Selsby JT, DiSilvestro RA, Devor STMg2+-creatine chelate and a low-dose creatine supplementation regimen improve exercise performanceJ Strength Cond Res.(2004 May)
    12. ^Galvan E, Walker DK, Simbo SY, Dalton R, Levers K, O'Connor A, Goodenough C, Barringer ND, Greenwood M, Rasmussen C, Smith SB, Riechman SE, Fluckey JD, Murano PS, Earnest CP, Kreider RBAcute and chronic safety and efficacy of dose dependent creatine nitrate supplementation and exercise performanceJ Int Soc Sports Nutr.(2016 Mar 31)