What is creatine?
Creatine is a substance that is naturally produced in the body and consists of 3 amino acids (L-arginine, glycine and methionine). In the body, creatine binds with phosphate and is therefore a fast source of energy in the form of creatine phosphate, where a phosphate molecule is donated to adenosine diphosphate (ADP) to form adenosine triphosphate (ATP) (energy) (1). This process is particularly relevant in explosive work. Creatine phosphate is found in large quantities in skeletal muscle and the heart (2).
When the body produces energy, whether from carbohydrate, fat or ketones, it ends up as ATP. Then, when the cells use ATP as energy, one or two phosphate molecules are released so we are left with ADP and adenosine monophosphate (AMP). The creatine phosphate stores in cells donate a phosphate molecule to ADP, so this molecule now becomes ATP (3,4,5,6).
By increasing the total amount of creatine phosphate, the recovery from ADP to ATP can occur faster and for longer.
What kind of creatine is best?
There's no doubt about it, although fitness brands would like to tell you otherwise.
Creatine monohydrate is the most common form of creatine and the most tested (7), as well as the cheapest. This form can also be found as "micronized creatine", which really just means that the particle size is smaller, providing better solubility in water, but has the same effect as "regular" creatine monohydrate.
Creatine hydrochloride (Creatine HCl) is a creatine molecule bound with hydrocholridic acid. Manufacturers claim that this binding allows a lower dosage, but this has not been tested adequately nor with convincing results.
Buffered creatine (Kre-Alkylyn) is said to improve the effect of creatine monohydrate due to a higher pH value, which should allow an easier absorption into the muscle tissue. However, no significant difference is seen in trained individuals (8).
Creatine ethyl ester increases the amount in muscle tissue less than creatine monohydrate (9). A direct comparison of the effect of creatine monohydrate against creatine ethyl ester shows that creatine ethyl ester is also less effective. At the same dosage as creatine monohydrate, creatine ethyl ester also does not appear to increase fluid volume in 28 days (10).
Remember that creatine binds more fluid, which we want, as it means a larger store of creatine phosphate in the muscle.
There are several other forms of creatine, but the most effective and cheapest is creatine monohydrate.
Creatine and power output?
Creatine monohydrate supplements improve power output if taken continuously, regardless of gender, for a period of 8 weeks. Specifically, improvements of 7 kg more in bench press and 10 kg more in squat (11,12).
Creatine and sprint performance
The restitution period between sprint sets is crucial for the amount of creatine phosphate that can be regenerated (13) and its rate is strongly related to performance during these sprints (14).
Therefore, creatine supplementation appears to be effective in increasing power output in anaerobic cardiovascular exercise, including sprints (15,16,17,18) and has been shown to increase acid threshold and time to willpower exhaustion after only 6 days of 20 g creatine per day divided into 4 doses of 15 g glucose (19).
However, creatine supplementation does not appear to have any direct performance optimising effect on longer duration events that do not consist of sprints.
Creatine and muscle building?
A short-term supplementation of 20 g creatine monohydrate with dextrose has been shown to increase the diameter of muscle fibres, independently of protein synthesis, as an increased amount of fluid in the muscle increases their size (20).
This effect on muscle cells may also decrease the burning of protein, which increases nitrogen balance, and may therefore indirectly contribute to increased muscle mass (21).
Creatine monohydrate has been known to have an anti-catabolic effect (limit muscle breakdown). It has been shown that an intake of 12 g creatine monohydrate per day for two weeks, before an hour endurance test at 65-70% VO2 max, can lead to an increase in lactate and tryptophan/BCAA ratio, and an attenuated increase in serum protein waste, indicating an anti-catabolic effect (22).
Are there any side effects?
There are no studies showing dangerous/harmful side effects of creatine intake, even at high doses. What has been found is that high acute intake can lead to stomach upset and cramping (from lack of fluids) (23,24,25).
A daily dose of 5 g has been shown to have no side effects (26) and 10 g has been used daily for 310 days in elderly people (57 +/- 11.1 years) with no significant differences from placebo (23).
Should I take creatine with carbohydrate?
Insulin secretion appears to have an association with creatine supplementation. However, there is a clinically significant correlation only in the first few days of a loading phase, when creatine stores are smaller (27). This effect is due to a greater secretion of insulin and appears to be independent of creatine transporters (28, 29). However, this effect seems to disappear as soon as creatine stores are filled.
How much creatine should I have and when?
Should I just eat the whole glass once, should it be loaded and can I take it forever?
Creatine can be taken with or without a loading phase. A loading phase fills up the stores faster, but in the long run it makes no difference.
In a loading phase, 0.3 g per kg body weight is typically taken for 5-7 days, after which 0.03-0.06 g per kg body weight is taken daily.
If you weigh 80 kg, a loading phase would look like this:
Days 1-7: Take 80*0.3 = 24 g per day divided into 4 doses (to avoid stomach upset).
Then: take 80*0.03= 2.4 g or 80*0.06= 4.8 g per day.
You can easily take 0.03-0.06 g per kg body weight continuously.
Personally, I'd go with 4-5g of creatine monohydrate a day, and take it at the time that suits you best!
Who should take creatine as a supplement?
If you are a strength trainee and want to be stronger and have more muscle mass, I would definitely recommend creatine monohydrate. It's super cheap, and one of the most well-documented supplements.
If you do sports that involve sprints, I would also recommend creatine as a starting point. Especially if you have a big focus on strength/power training, which you should have!
I would recommend it to people who play sports like floorball, ice hockey, handball but also football, where creatine has been shown to have a positive effect on performance (30).
Sources:
- Darrabie MD, et al. AMPK and substrate availability regulate creatine transport in cultured cardiomyocytes. Am J Physiol Endocrinol Metab(2011).
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- Mujika I, Padilla S. Creatine supplementation as an ergogenic aid for sports performance in highly trained athletes: a critical review. Int J Sports Med. (1997)
- Terjung RL, et al. American College of Sports Medicine roundtable. The physiological and health effects of oral creatine supplementation. Med Sci Sports Exerc(2000).
- Guzun R, et al. Systems bioenergetics of creatine kinase networks: physiological roles of creatine and phosphocreatine in regulation of cardiac cell function. Amino Acids(2011).
- Adhihetty PJ, Beal MF. Creatine and its potential therapeutic value for targeting cellular energy impairment in neurodegenerative diseases.Neuromolecular Med. (2008)
- Dash AK, Mo Y, Pyne A. Solid-state properties of creatine monohydrate. J Pharm Sci(2002).
- Jagim AR, et al. A buffered form of creatine does not promote greater changes in muscle creatine content, body composition, or training adaptations than creatine monohydrate. J Int Soc Sports Nutr(2012).
- 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)
- Spillane 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 (2009)
- Dempsey RL, Mazzone MF, Meurer LN. Does oral creatine supplementation improve strength? A meta-analysis. J Fam Pract(2002).
- Branch JD. Effect of creatine supplementation on body composition and performance: a meta-analysis. Int J Sport Nutr Exerc Metab(2003).
- Bogdanis GC, et al. Recovery of power output and muscle metabolites following 30 s of maximal sprint cycling in man. J Physiol(1995).
- Mendez-Villanueva A, et al. The recovery of repeated-sprint exercise is associated with PCr resynthesis, while muscle pH and EMG amplitude remain depressed. PLoS One. (2012)
- Havenetidis K, Bourdas D. Creatine supplementation: effects on urinary excretion and anaerobic performance. J Sports Med Phys Fitness(2003).
- Koçak S, Karli U. Effects of high dose oral creatine supplementation on anaerobic capacity of elite wrestlers. J Sports Med Phys Fitness(2003).
- Eckerson JM, et al. Effect of creatine phosphate supplementation on anaerobic working capacity and body weight after two and six days of loading in men and women. J Strength Cond Res(2005)
- Okudan N, Gokbel H. The effects of creatine supplementation on performance during the repeated bouts of supramaximal exercise. J Sports Med Phys Fitness(2005).
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- Safdar A, et al. Global and targeted gene expression and protein content in skeletal muscle of young men following short-term creatine monohydrate supplementation. Physiol Genomics(2008).
- Parise et al. ffects of acute creatine monohydrate supplementation on leucine kinetics and mixed-muscle protein synthesis. (2001)
- Tang FC, Chan CC, Kuo PL. Contribution of creatine to protein homeostasis in athletes after endurance and sprint running. Eur J Nutr(2013).
- Groeneveld GJ, et al. Few adverse effects of long-term creatine supplementation in a placebo-controlled trial. Int J Sports Med. (2005)
- Greenwood M, et al. Creatine supplementation during college football training does not increase the incidence of cramping or injury. Mol Cell Biochem(2003).
- Lopez RM, et al. Does creatine supplementation hinder exercise heat tolerance or hydration status? A systematic review with meta-analyses. J Athl Train. (2009)
- Shao A, Hathcock JN. Risk assessment for creatine monohydrate. Regul Toxicol Pharmacol(2006).
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