Creatine Purity and Impurities: The 2026 Reference
Last updated 7 July 2026
The parameters that define creatine quality, the EFSA impurity limits behind them, and how to read them on a certificate of analysis.
Creatine monohydrate quality is defined by four things, and only one of them is the purity number on the bag: HPLC assay, the impurity panel (creatinine, DCD, DHT), heavy metals, and the documentation that proves them per lot. A certificate of analysis that reports 99.9 percent purity but stays silent on impurities tells you almost nothing, because the impurities are where cheap creatine fails.
The spec that actually matters
| Parameter | EFSA-referenced limit | Premium target | Method |
|---|---|---|---|
| HPLC assay | 99 percent minimum | 99.9 percent | HPLC |
| Creatinine | 100 mg/kg | 30 ppm or lower | HPLC |
| Dicyandiamide (DCD) | 50 mg/kg | Not detected | HPLC |
| Dihydrotriazine (DHT) | Not detectable (3 mg/kg) | Not detected | HPLC |
| Lead / Arsenic / Cadmium | 1.0 ppm each | Below limit | ICP-MS |
| Mercury | 0.1 ppm | Below limit | ICP-MS |
| Identity | Conforms | CAS 6020-87-7 | FT-IR / HPLC |
The limits reference the EFSA opinion on creatine monohydrate. The point of listing them is simple: quality is defined as much by what is absent as by the assay figure.
Why impurities, not purity, separate good creatine from cheap
Creatine is synthesised, and the synthesis route and process control decide what residues are left behind. A peer-reviewed survey of 33 commercial creatine products (Moret et al., Food Chemistry, 2011) found that around 44 percent exceeded the EFSA creatinine limit and roughly 15 percent exceeded the DCD limit, so about half exceeded an EFSA-referenced limit for at least one impurity. Purity marketing hides this, because a lot can assay at 99.9 percent creatine and still carry creatinine or DCD over the line.
- Creatinine is what creatine degrades into. High creatinine means an old, hot-processed, or poorly stored lot.
- DCD (dicyandiamide) is a synthesis residue tied to the precursor and the process. Cheap generic material is where it shows up.
- DHT (dihydrotriazine) should be not detected at all. It is the marker reputable buyers watch most closely.
How to verify it, honestly
Assay and impurities need HPLC; heavy metals need ICP-MS. Neither can be checked with basic equipment, so the credible signal is a lot-specific certificate of analysis plus, for serious volumes, periodic accredited third-party testing (ISO 17025). A supplier CoA alone is a starting point, not proof. See our creatine supplier CoA checklist for what to demand, and the specimen certificate of analysis for the format Creavante documents every lot to.
Related: is creatine from China safe? covers where these impurities come from, and creatine mesh sizes explained covers the one quality variable that is about physics, not chemistry.
Frequently asked
What impurities matter most in creatine monohydrate?
Three: creatinine (a degradation product), dicyandiamide (DCD, a synthesis residue), and dihydrotriazine (DHT). EFSA-referenced limits are creatinine 100 mg/kg, DCD 50 mg/kg, and DHT not detectable below 3 mg/kg. Heavy metals (lead, arsenic, cadmium, mercury) and microbiology complete the panel. A certificate that shows only the assay percentage is incomplete.
What purity should bulk creatine monohydrate have?
Supplement-grade creatine is quoted by HPLC assay. 99 percent is the baseline, reputable producers target 99.5 percent and above, and premium grades reach 99.9 percent. Purity alone is not enough: a 99.9 percent lot can still carry creatinine or DCD above the EFSA limits, which is why the impurity panel matters.
How is creatine purity actually tested?
By HPLC (high-performance liquid chromatography) for assay and organic impurities, and by ICP-MS for heavy metals. These are lab instruments, not something a supplier can verify with basic equipment, so the credible signal is a lot-specific certificate of analysis, ideally backed by periodic accredited third-party testing.