Someone holding an old tub of creatine wants one number, and the literature can give a better one than most supplements can: dry creatine monohydrate is among the most chemically stable things sold in a tub. But the figure every answer repeats traces back to a single source that was never published in a journal, the picture changes completely once water is involved, and the date printed on the label does not mean what most people assume. This page reports what was measured; it is research journalism, not usage guidance, per our editorial standards.
What "going bad" means for creatine
Creatine has one main way to break down: it closes into a ring and becomes creatinine, losing a water molecule in the process. Creatinine has no creatine activity — the body excretes it — and it is the same compound a blood test reads when estimating kidney function, which is a separate source of confusion covered on what creatine means in bloodwork.
So "does creatine expire" is really "how fast does creatine turn into creatinine," and that depends almost entirely on one thing: whether it is dry.
Dry powder: the numbers, and where they come from
The figures every stability answer quotes come from a 2011 review in Amino Acids. It reports that creatine monohydrate powder showed no detectable creatinine — below the 67 ppm quantification limit — after more than three years at room temperature and at 40°C (104°F), and that even stored at 60°C (140°F), creatinine (106 ppm) appeared only after 44 months (Jäger et al. 2011, PMID 21424716).
Two things about that figure are worth stating, because no seller page states them:
- It is cited to one source that is not a journal paper. The review's reference is "Jäger R (2003) The use of creatine monohydrate in sports nutrition, Freising, Germany." It is a monograph by the review's own lead author, not a peer-reviewed stability study.
- The review has industry ties. Its first two authors are listed at Increnovo LLC, a private company in Milwaukee, and a third was employed by a US supplement trade association, which the paper discloses.
Neither point makes the number wrong. Independent chemistry agrees with its direction: Uzzan and colleagues, working on creatine in food systems, "confirmed that creatine stability in the crystal form is very high as long as it does not reach the deliquescence state" — the point at which the powder has absorbed enough moisture to start dissolving (Uzzan et al. 2009, PMID 19635041). What the two points do mean is that "three years at 40°C" is a single dataset from one source, repeated so often it reads like a consensus.
In water: days, not years
Here the literature is independent and unambiguous. The same review summarises solution studies going back to the 1920s: creatine was relatively stable at near-neutral pH (6.5–7.5), but after only three days at 25°C it had degraded 4% at pH 5.5, 12% at pH 4.5 and 21% at pH 3.5 (Jäger et al. 2011). Acid speeds the reaction.
A pharmaceutics study measured it directly in a product. Creatine drinks made from effervescent powder lost 90% of their creatine within 45 days at room temperature, and 80% even refrigerated; some of what remained crystallised out of solution (Ganguly et al. 2003, PMID 12916907). This is why ready-to-drink creatine is the one format where stability, rather than effect, is the whole story.
Once creatine is inside a food
Creatine blended into a moist product behaves more like a solution than a powder. A 2019 study of creatine monohydrate in pet foods — co-authored by an employee of AlzChem, the German maker of Creapure — found that in a dry extruded food stored at 25°C and 60% humidity for 15 months, creatine fell 63% while creatinine rose 39%, and loss was faster at 40°C (van der Poel et al. 2019, PMID 31074123). The authors concluded it was difficult to guarantee creatine content in such foods.
That finding is about dog food, not supplements, but it is the closest measured analogue to a gummy or a bar. It fits the label-versus-content problem already documented for creatine gummies, where independent testing found some products carrying little or none of their labelled creatine.
What the date on the tub actually is
Most people read a printed date as a safety line. For US dietary supplements it is neither required nor defined by regulation. When FDA finalised its manufacturing rule for supplements in 2007, it declined to require one — the comments it received did "not persuade us to alter our position not to require that you establish an expiration date for your product" — and added one sentence of expectation: "any expiration date that you place on a product label (including a 'best if used by' date) should be supported by data" (72 FR 34752, 25 June 2007).
So a date on a creatine label is the manufacturer's claim about how long the product holds its labelled amount, not a regulator's limit. Two identical powders can carry different dates simply because their makers chose different stability programmes.
Clumping, smell and colour
Clumping is the sign people ask about most, and it is informative about one thing only: the powder has taken up moisture, which is the condition Uzzan's work identifies as the point where stability ends. It does not tell anyone how much creatine has turned to creatinine — that needs a lab. No study found for this page tested clumped consumer powder, and no study tested an opened tub at all.
Formats differ more in stability than in effect: the same chemistry that makes a dry powder last makes a pre-mixed drink or a moist chew fragile, which is also a thread through creatine pills versus powder and micronised creatine.
What is not established
- Opened-tub stability has never been measured. Every figure above is sealed powder, controlled solutions or manufactured food.
- The multi-year powder figure has one source. It is plausible and independently consistent with crystal-state chemistry, but it has not been reproduced in a peer-reviewed stability study found for this page.
- Expired creatine has no trial. Whether an old product is safe for a given person is not a question the literature answers; it belongs with a pharmacist or clinician.
- Other creatine salts were not covered here. The 2011 review notes some salts appear less stable than monohydrate, with tri-creatine citrate reaching 770 ppm creatinine after 28 days at 40°C.
Sources and dates
- Jäger R, Purpura M, Shao A, Inoue T, Kreider RB. Analysis of the efficacy, safety, and regulatory status of novel forms of creatine. Amino Acids 2011;40:1369–83 — PMID 21424716, full text read 2026-09-23 incl. reference list and author affiliations
- Uzzan M, Nechrebeki J, Zhou P, Labuza TP. Effect of water activity and temperature on the stability of creatine during storage. Drug Dev Ind Pharm 2009;35:1003–8 — PMID 19635041
- Ganguly S, Jayappa S, Dash AK. Evaluation of the stability of creatine in solution prepared from effervescent creatine formulations. AAPS PharmSciTech 2003;4:E25 — PMID 12916907
- van der Poel AFB, Braun U, Hendriks WH, Bosch G. Stability of creatine monohydrate and guanidinoacetic acid during manufacture and storage of dog foods. J Anim Physiol Anim Nutr 2019;103:1242–50 — PMID 31074123
- US Food and Drug Administration. Current Good Manufacturing Practice in Manufacturing, Packaging, Labeling, or Holding Operations for Dietary Supplements; Final Rule. 72 FR 34752, 25 June 2007 — full text read 2026-09-23