Table 5.

Classification of evidence to support bioavailability, efficacy, and safety for alternative forms of creatine available on amazon.

Type of Creatine	Level of Evidence	Summary of Evidence Available
Creatine Phosphate	No Evidence	Not Available
Creatine Alpha-Ketogluterate	No Evidence	Not Available
Tri-Creatine Malate	No Evidence	Not Available
Creatine Ethyl Ester Malate	No Evidence	Not Available
Creatine Gluconate	No Evidence	Not Available
Di-creatine Malate	No Evidence	Not Available
Creatinol-O-Phosphate (COP)	No Evidence	Intramuscular and intravenous administration of COP ↑ handgrip performance, but no studies have evaluated if it has any effect on muscle creatine levels or exercise performance [35, 43]
Buffered or KreAlkalyn® Creatine	Some Evidence	Recommended doses and loading/maintenance equivalent doses did not provide greater changes in muscle creatine, body composition, strength, or anaerobic capacity compared to CM [27, 35]
Creatine Pyruvate	Some Evidence	↑ intermittent handgrip exercise of maximal intensity and may have benefits with endurance exercise, but conflicting evidence exists on benefits with endurance exercise [25, 35, 64]
Creatine Citrate	Some Evidence	Studies provide evidence it can increase blood creatine levels in a similar manner as CM and there is some data supporting an ergogenic benefit, but the impact of supplementation has not been assessed on muscle or brain creatine content. No studies currently indicate it is more effective or safe than CM [16, 19, 24, 25, 35, 61]
Creatine Hydrochloride	Some Evidence	This creatine salt should disassociate into creatine and HCL and is bioavailable, but there is no evidence that it is absorbed more effectively than CM in humans, promotes greater muscle creatine retention than CM at same dosages, or that lower doses are more effective than standard CM doses [15, 35, 63, 71]
Creatine Ethyl Ester (CEE)	Some Evidence	Likely that some of the ingredient is degraded into creatinine during normal digestion, but some creatine will be delivered to blood. Supplementation has shown increases in muscle creatine content vs. placebo after 27 days of supplementation, but less than those taking CM. Supplementation during resistance training also showed increases in body weight and leg press strength while body fat decreased, but results were not better than using CM. No evidence that ingesting recommended dosages of supplement is more effective than recommended dosages of CM [2, 35, 59]
Creatine Nitrate	Some Evidence	Some evidence to support it is a bioavailable source of creatine in proportion to the amount of creatine delivered during the loading phase, but not more bioavailable than CM when equivalent doses are ingested. Some evidence to suggest supplementation provides an ergogenic effect for muscle endurance, but since it was unrelated to changes in muscle creatine content the benefit may come from the nitrate as opposed to creatine. Remains to be determined if supplementation has any additional benefit than simply co-ingesting CM with a source of nitrate [12, 17, 28, 29, 35, 50]
Magnesium Creatine Chelate	Some Evidence	No evidence it is more bioavailable, efficacious, and/or safer than CM and limited evidence it is as effective as CM to increase strength, power, and muscle endurance [6, 35, 55, 68]
Creatine Anhydrous	Not Provided	No data available, but this compound is 100% creatine and likely has similar effects to CM
Free Acid Creatine	Not Provided	Not available