Creatine monohydrate manufactured in Germany involves adding acetic acid to sodium sarconsinate, heating, adding cyanamide, cooling to promote crystallization, separation and filtration, and drying has been reported to produce 99.9% pure creatine monohydrate with no contaminants.
Meanwhile, other sources of creatine monohydrate that have different starting materials (e.g., sarcosinates and O-alkylisourea, sarcosinates and S-alkylisothiourea) and methods of creatine synthesis, particularly from sources produced in China, have been found to contain up to 5.4% dicyandiamide, 0.09% dihydrotriazine, 1.3% creatinine, dimethyl sulphate, thiourea, and/or higher concentrations of heavy metals like mercury and lead due to use of different chemical precursors, poorly controlled synthesis processes, and/or inadequate filtration methods that more readily produce these contaminants [197]. While the effects of ingesting these compounds on health are unknown, contamination with dihydrotriazine has been suggested to be of greatest concern since it is structurally related to carcinogenic compounds [197]. For this reason, German sourced creatine monohydrate has been primarily used in research to establish safety and efficacy and is therefore the recommended source of creatine monohydrate to use in dietary supplements [2, 187].