Labdoor analyzed 25 best-selling creatine supplements in the United States. Our analysis quantified levels of total creatine and creatinine, and recorded presence/absence data for 35 inactive ingredients.
The tested products recorded minor label claim variances for creatine content, ranging from -2.5% to +16% (-0.08g to +0.70g), with the average product deviating off its claim by only 2.6% (0.08g).
25% of tested products recorded elevated levels of creatinine, a waste product formed during creatine metabolism. All products passed heavy metal screens for arsenic, lead, cadmium, bismuth, antimony, and silver content.
These products’ creatine claims ranged from -2.5% to +16% vs. their stated label claims, with the average product deviating off its creatine claim by only 2.6%.
11 products recorded a positive variance, indicating that actual creatine content exceeded its claim. Only 3 products recorded less creatine than indicated on their Supplement Facts labels.
6 of 25 products exceeded 40mg/serving of creatinine content, which is equivalent to 75% of the upper limit for creatinine. Products with elevated creatinine levels may add to the existing backlog of already overworked and functionally-impaired kidneys.
Creatinine is recognized as the final breakdown product of creatine metabolism; this conversion is irreversible in vivo.
All products in this report were screened by Inductively Coupled Plasma (ICP)-based techniques for the presence of heavy metals. Samples of each product passed all six heavy metals assays, indicating that samples contained under 1 PPM (part per million) each of arsenic, lead, cadmium, bismuth, antimony, and silver compounds.
3 of 25 products recorded high levels of added sugars. Worst Offender: Body Fortress Super Advanced Creatine, which recorded 33g of added sugars per serving. This amount exceeds new World Health Organization (WHO) draft guidelines for added sugar intake: 5% of daily caloric intake, or 25g daily based on a 2000 calorie diet.
- While there is evidence of carbohydrates increasing creatine uptake by muscle cells, we discourage excessive intake of added sugars for this purpose.
Studies have estimated that approximately 1.5-2.0% of creatine stores are degraded each day; for a 70kg individual, this equates to 2g. Approximately 2g of creatine need to be reintroduced into the body daily to maintain muscle mass and strength output, with 1g hypothesized to be produced endogenously every day. Based on this research, about 1g of creatine should be consumed through diet or supplementation on a daily basis.
2 of 25 products recorded less than 1g of creatine per serving, an amount that may not adequately restore normal creatine levels, even in normoweight, lightly active individuals. Those following restrictive diets (e.g. vegetarians) are more likely to have chronically low creatine levels; from a nutritional standpoint, these populations may benefit most from supplementation.
8 of 25 products recorded natural and/or artificial flavors. 7 products recorded the artificial sweetener sucralose (Splenda®), making it the second most popular excipient in creatine supplements.
5 products had one or more artificial coloring agents, which included FD&C Red 40, FD&C Blue 1, FD&C Yellow 5, and FD&C Yellow 6. The controversial additives caramel color and titanium dioxide were also flagged in two products.
The waste product creatinine was also quantified. Values representing creatinine content resembled an inverse bell distribution, where the majority of products fall into one of two extremes (high and low values). 13 products recorded less than 5mg of creatinine per serving and 8 products were found to have over 35mg/serving. The worst offender recorded 94.4mg creatinine/serving.
In our analysis, creatinine content was positively correlated to the presence of organic acids and, according to a crude quantitative analysis, the acid’s hygroscopicity (the ability to attract and hold water). The presence of water is thought to catalyze the conversion of creatine into creatinine. This analysis was confounded by: Insufficient label information establishing total amounts of recorded acids. As well as the lack of available information establishing hygroscopicity of all recorded organic acids.
Labdoor based its efficacy calculations on the effective concentration of creatine monohydrate in each sample. When other forms of creatine were present, conversion factors were utilized to translate the data into units of creatine monohydrate.
Actual creatine content ranged from 0.8g to 8.1g per serving, with the average product recording 4.2g per serving.
A typical dosing regimen includes a loading dose of 20g daily (taken as 4 separate doses) for up to 5-7 days followed by a maintenance dose of 2g daily – this dosing course has shown efficacy in enhancing athletic performance in adults over 19 years of age. A larger maintenance dose, about 5g/day, may be more efficacious for those with added muscle mass and higher activity levels.
Creatine monohydrate is the most popular form of the supplement, present either on its own or as part of a creatine blend in 21 of 25 tested products. This is the reference form of creatine, used most often in clinical studies. Other forms, including creatine hydrochloride, present in 6 products, have not been extensively studied and their claims of increased efficacy are not founded in scientific research. Limited evidence suggests that magnesium-chelated creatine, present in 3 products, acts with a potency similar to that of the monohydrate form, but may not cause water-weight gain.
Creatine’s efficacy in increasing lean muscle mass, strength output, and overall athletic performance depends on a variety of factors, including age, fitness level, type and duration of physical activity, and dose. Many studies show evidence of benefit for repetitive, high-intensity, and short duration exercise, particularly in younger populations. However, creatine does not seem to improve endurance or performance in highly trained athletes. Dosing regimens may need to be adjusted to achieve peak effect for individual purposes.