Supplement marketing loves the word "advanced." If a basic ingredient has been studied for decades, someone will sell a tweaked version as better absorbed, more potent, and gentler on the stomach. Creatine ethyl ester (CEE) is a textbook example. A 2009 randomized, double-blind trial in the Journal of the International Society of Sports Nutrition put it head to head with plain creatine monohydrate. The newer form did not come out ahead.
What CEE Claims
Creatine monohydrate is the standard, the form most research has used. Many alternative formulations were developed mainly to maximize creatine absorption, and CEE was alleged to increase creatine bioavailability. The pitch is simple: attach an ethyl ester group, and creatine supposedly moves into the bloodstream and muscle more efficiently, so you need less and get more.
That is a testable claim, and Spillane and colleagues tested it. The question was whether CEE would raise serum and muscle creatine and improve training outcomes at least as well as monohydrate.
Study Design and Doses
The researchers recruited 30 men who were not resistance-trained. Participants were randomly assigned, in a double-blind manner, to one of three groups:
- Placebo (maltodextrose)
- Creatine monohydrate (CRT)
- Creatine ethyl ester (CEE)
Everyone followed a heavy resistance training program for seven weeks. The supplement protocol was a loading phase of 0.30 g per kg of fat-free body mass (about 20 g/day) for five days, then a maintenance dose of 0.075 g/kg fat-free mass (about 5 g/day) for 42 days. The groups got matched doses, so any difference should come from the form of creatine rather than the amount.
The team measured body composition, muscle mass, strength and power, serum and muscle creatine, and serum creatinine.
The Serum Creatinine Finding
This was the most telling result. Serum creatine was significantly higher in the placebo group (p = 0.007) and the monohydrate group (p = 0.005) than in the CEE group. A "better absorbed" creatine that leaves less creatine in the blood is hard to square with the marketing.
Serum creatinine, the breakdown product of creatine, was higher in the CEE group than in placebo (p = 0.001) or monohydrate (p = 0.001). It was elevated at days 6, 27, and 48. This pattern fits CEE degrading into creatinine rather than being used as creatine. That is an interpretation of the data, and the trial measured blood markers, not the chemistry of the degradation itself. But the direction is clear: the ester form ended up as more of the waste product.
There is a practical side effect. Serum creatinine is a standard marker doctors use when estimating kidney function. A supplement that pushes it up can make routine bloodwork harder to read. The paper does not report kidney damage, and a higher creatinine here should not be read as evidence of harm. But if you take creatine and get blood tests, tell your clinician so they can interpret the numbers in context.
Muscle Creatine Results
The muscle data are more nuanced. Total muscle creatine was significantly higher in both the monohydrate group (p = 0.026) and the CEE group (p = 0.041) than in placebo, and there was no significant difference between the two creatine forms. So CEE did raise muscle creatine compared with placebo.
The authors still concluded that CEE was not as effective as monohydrate at increasing serum and muscle creatine. Muscle levels did not differ significantly between the two creatine groups, but the serum results clearly favored monohydrate, and CEE offered no advantage on any outcome.
Did Strength or Size Differ?
No, and this applies to every group. Body composition, body water, muscle strength, and power all changed significantly over time, but there were no significant differences between groups. The placebo group improved along with the creatine groups.
The authors concluded that the improvements were most likely due to the training itself rather than supplementation. This was a 7-week trial in untrained beginners, a population that gains quickly from almost any well-structured program, which can mask smaller supplement effects. The trial can't say CEE fails to build muscle in every context, only that it showed no benefit here. It also did not show monohydrate beating placebo on strength in this sample, so the study is better read as "CEE offered no advantage" than as a victory lap for monohydrate performance.
Bottom Line and Practical Takeaways
The marketing promised better absorption. The data showed lower serum creatine, higher serum creatinine, similar muscle creatine to monohydrate, and no extra gains in body composition, strength, or power.
- Stick with creatine monohydrate. It is the best-studied form and typically the cheapest. A common intake is 3-5 g/day.
- Loading is optional. This trial used a five-day load of about 20 g/day, but a steady daily dose is a common alternative that gets you to the same place more slowly.
- Don't pay a premium for "advanced" forms unless there is solid head-to-head evidence, which for CEE points the other way.
- Mind your bloodwork. High serum creatinine, especially with CEE, can confuse kidney blood tests. Mention your supplements to your doctor.
- Training comes first. In this trial, the program did most of the work.
Source
Spillane M, et al. The effects of creatine ethyl ester supplementation combined with heavy resistance training on body composition, muscle performance, and serum and muscle creatine levels. J Int Soc Sports Nutr. 2009. DOI: 10.1186/1550-2783-6-6. PubMed: 19228401.
