Creatine 101

This article was written by our regular contributor; registered dietitian – Maeve Hanan.

Creatine is one of the most popular and best researched sports supplements on the market. But as there are common misconceptions surrounding this supplement, this article will walk you through key facts related to creatine.

What is Creatine?

Creatine is a naturally occurring compound made of the amino acids glycine, arginine, and methionine (1, 2). Roughly 1g of creatine per day is produced by the body and creatine can be obtained from dietary sources or supplements (2). 

Roughly 95% of the creatine in our body is found in skeletal muscle, with smaller amounts being present in the brain, and for men, in the testes (1).

What Does Creatine Do?

There are three main energy systems in the body: the aerobic system, the anaerobic system and the ATP-phosphagen system. All of these systems use a molecule called ATP (adenosine triphosphate) to carry and release energy.  

During intense bursts of activity that last only a few seconds, such as sprinting, a jump or maximal lifts, the ATP-phosphagen system is used. Our body generates energy (in the form of ATP) from a molecule called phosphocreatine (PCr). ATP is broken down to ADP and energy is released (1, 3). PCr is capable of reforming ATP very quickly, but only a very small amount is stored in the muscles and so the energy supply is limited (1, 3). This is replenished through rest periods and also through external sources such as food and creatine supplementation. Hence, creatine helps with high-intensity performance and recovery.

As discussed below, creatine also helps with increasing muscle mass, supporting sports performance, cognition and healthy ageing. 

The Benefits of Creatine

Creatine monohydrate (CM) is the most researched form of creatine. The International Society of Sports Nutrition states that “creatine monohydrate is the most effective ergogenic [i.e. performance improving] nutritional supplement currently available to athletes with the intent of increasing high-intensity exercise capacity and lean body mass during training” (1).

Increases exercise performance

CM supplementation has been found to boost performance by roughly 10-20% in a variety of age groups, particularly for short-burst high-intensity (anaerobic) exercise like sprinting and weight lifting (1).

Increases muscle mass and strength 

Creatine also promotes muscle gain by drawing water into the muscle, increasing levels of the hormone IGF-1 and improving performance ability and recovery (1, 4). Based on the available evidence, the European Food Safety Authority (EFSA) support a cause and effect relationship between consuming creatine along with resistance training for improving muscle strength in adults over the age of 55 (5).  

Other benefits of using creatine supplements for sports includes (1):

• Reduced injuries
• Improved recovery 
• Enhanced  glycogen synthesis
• Improved heat tolerance
• Protection of the brain and spinal cord during contact sports  

Mood and cognitive benefits 

Creatine also supplies energy to the brain and has been found to improve cognitive function and memory and to reduce mental fatigue (6, 7, 8, 9). 

Creatine supplementation may also have antidepressant effects based on some early clinical studies (1, 10). 

Improved health in older adults

Although there is less supporting evidence, creatine has been associated with other markers of improved health in older age in terms of (1, 11, 12, 13):

• Bone health
• Cholesterol levels
• Blood glucose control

Differences in Response 

People may respond to creatine in different ways. For example, a small study from 2004 found that men who had a lower level of creatine in their muscles before supplementation and more type 2 muscle fibres (A.K.A. ‘fast twitch’ muscle fibres) achieved more strength gains from creatine supplementation (14). 

Those with higher baseline levels of creatine are sometimes called ‘non-responders’ as it is thought they may not achieve the same benefits as those with lower baseline levels or different muscle fibre types. Based on a few small studies, it is thought that 20-30% of people may be ‘non-responders’ (14, 15).   

For example, vegetarians may have a better response to creatine supplements as they often have less creatine stored in their muscle prior to supplementation (9, 14, 16). 

Findings are mixed about the impact of creatine on females vs. males, and the impact on females is an understudied area overall. However, some studies have also found that females may have lower creatine stores and a lower dietary intake, and may also need higher doses than males to achieve a similar response (17 , 18, 19). Creatine supplementation has been associated with improvements in strength and exercise performance for pre-menopausal women, and in muscle size and function, bone health, mood and cognition for post-menopausal women (17). 

Are There Any Side Effects of Taking Creatine?

This is considered to be a safe and generally well-tolerated supplement. No harmful effects have been seen from taking up to 30g per day for 5 years (1). 

There have been some reports of digestive issues, muscle cramping, dehydration, or injuries linked with creatine supplements, but these are not backed by the current evidence base (1). 

For those who do experience side effects like bloating, it may help to take this after a meal rather than on an empty stomach and in smaller doses throughout the day. 

Weight gain is a common side effect, but this is due to increased muscle and water retention rather than an increase in fat (1, 3). However, some ‘gainer’ supplements that contain creatine can also be high in calories.   

One of the most common myths about creatine is that it is damaging to the kidneys. This is because creatine is filtered through the kidneys and increases levels of creatinine in the body, which is a marker of poor kidney function. However,  although creatinine levels may rise, kidney damage has not been found as a result of creatine supplementation in either healthy adults and those with kidney disease (1, 20, 21). For example, a case report of a man with one kidney found no damaging effect from taking a loading dose of 20 g of creatine per day for 5 days, followed by 5 g per day for 30 days (22). 

Creatine supplements usually caution that these are not intended for use by those under the age of 18. However the International Society of Sports Nutrition  recommends that this can be considered for younger athletes who are involved in professional or competitive sports if they consume a well-balanced diet and understand how to use creatine appropriately, in the recommended amounts (as outlined below) (1).

How to Take Creatine?

This is naturally present in red meat and seafood, and those who eat animal-based products consume roughly 1g of creatine per day (1, 2). For example, 450g of raw salmon or beef provides roughly 1–2 g of creatine, so a typical portion of fish or red meat would provide around 0.25 – 0.5g of creatine (1). 

A higher dose of creatine can be taken as a supplement in powder, capsule or tablet form, or within other supplements. The most common form is creatine monohydrate powder that can be dissolved in water. 

Taking smaller creatine doses along with carbohydrate, or carbohydrate and protein, after exercise has been seen to increase creatine absorption and storage (1, 2, 3).  

When used for sports performance, creatine can be taken as a ‘loading phase’ followed by a ‘maintenance phase’. 

The loading phase can be done in a variety of ways, most commonly 20g (or 0.3g per kg) of CM per day split into 4 x 5g daily doses for 5 to 7 days (1, 3, 5).

A maintenance dose of 3-5g CM per day is commonly used, but some studies have found that larger athletes may need to take 5-10g CM per day (1).

For promoting general health, particularly as we age, it may be beneficial to consume 3g of creatine per day (1, 23).  

Take-Home Message

Creatine is a naturally-occurring substance in our body that can also be consumed in our diet or taken as a supplement. This plays an important role in energy regulation and studies have found that taking creatine supplements can help with increasing muscle mass and supporting sports performance, cognition and healthy ageing. 

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References

1. Kreider et al. (2017) “International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine”. J Int Soc Sports Nutr; 14: 18. [accessed September 2021 via: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5469049/] 
2. Cooper et al. (2012) “Creatine supplementation with specific view to exercise/sports performance: an update”. J Int Soc Sports Nutr; 9: 33. [accessed September 2021 via: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3407788/] 
3. Anita Bean (2017). Sports Nutrition, 8th Edition. Bloomsbury Sport, London.
4. Burke et al. (2008) “Effect of creatine supplementation and resistance-exercise training on muscle insulin-like growth factor in young adults”. Int J Sport Nutr Exerc Metab; 18(4):389-98. [accessed September 2021 via: https://pubmed.ncbi.nlm.nih.gov/18708688/]
5. EFSA (2016) “Creatine in combination with resistance training and improvement in muscle strength: evaluation of a health claim pursuant to Article 13(5) of Regulation (EC) No 1924/2006”. [accessed September 2021 via: https://www.efsa.europa.eu/en/efsajournal/pub/4400]
6. Pan & Takahashi (2007) “Cerebral energetic effects of creatine supplementation in humans”. Am J Physiol Regul Integr Comp Physiol; 292(4):R1745-50. [accessed September 2021 via: https://pubmed.ncbi.nlm.nih.gov/17185404/]  
7. Watanabe et al. (2002) “Effects of creatine on mental fatigue and cerebral hemoglobin oxygenation”. Neurosci Res; 42(4):279-85. [accessed September 2021 via: https://pubmed.ncbi.nlm.nih.gov/11985880/] 
8. McMorris et al. (2006) “Effect of creatine supplementation and sleep deprivation, with mild exercise, on cognitive and psychomotor performance, mood state, and plasma concentrations of catecholamines and cortisol”. Psychopharmacology; 185(1):93-103. [accessed September 2021 via: https://pubmed.ncbi.nlm.nih.gov/16416332/] 
9. Benton & Donohoe (2011) “The influence of creatine supplementation on the cognitive functioning of vegetarians and omnivores”. Br J Nutr; 105(7):1100-5. [accessed September 2021 via: https://pubmed.ncbi.nlm.nih.gov/21118604/] 
10. Kious et al. (2019) “Creatine for the Treatment of Depression”. Biomolecules; 23;9(9):406. [accessed October 2021 via: https://pubmed.ncbi.nlm.nih.gov/31450809/]
11. Chilibech et al. (2015) “Effects of Creatine and Resistance Training on Bone Health in Postmenopausal Women”. Med Sci Sports Exerc; 47(8):1587-95. [accessed September 2021 via: https://pubmed.ncbi.nlm.nih.gov/25386713/]  
12. Earnest et al. (1996) “High-performance capillary electrophoresis-pure creatine monohydrate reduces blood lipids in men and women”. Clin Sci (Lond); 91(1):113-8. [accessed September 2021 via: https://pubmed.ncbi.nlm.nih.gov/8774269/]
13. Gualano et al. (2011) “Creatine in type 2 diabetes: a randomized, double-blind, placebo-controlled trial”. Med Sci Sports Exerc; 43(5):770-8. [accessed September 2021 via: https://pubmed.ncbi.nlm.nih.gov/20881878/] 
14. Syrotuik & Bell (2004) “Acute creatine monohydrate supplementation: a descriptive physiological profile of responders vs. nonresponders”. J Strength Cond Res; 18(3):610-7. [accessed September 2021 via: https://pubmed.ncbi.nlm.nih.gov/15320650/]
15. Greenhalf et al. (1994) “Effect of oral creatine supplementation on skeletal muscle phosphocreatine resynthesis”. Am J Physiol; 266(5 Pt 1):E725-30. [accessed October 2021 via: https://pubmed.ncbi.nlm.nih.gov/8203511]
16. Burke et al. (2003) “Effect of creatine and weight training on muscle creatine and performance in vegetarians”. Med Sci Sports Exerc; 35(11):1946-55. [accessed September 2021 via: https://pubmed.ncbi.nlm.nih.gov/14600563/]
17. Ellery et al. “Creatine for women: a review of the relationship between creatine and the reproductive cycle and female-specific benefits of creatine therapy”. Amino Acids; 48(8):1807-17 [accessed September 2021 via: https://pubmed.ncbi.nlm.nih.gov/26898548/]
18. Smith-Ryan et al. (2021) “Creatine Supplementation in Women’s Health: A Lifespan Perspective”. Nutrients; 13(3): 877. [accessed October 2021 via: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7998865/]
19. Mihic et al. (2000) “Acute creatine loading increases fat-free mass, but does not affect blood pressure, plasma creatinine, or CK activity in men and women”. Med Sci Sports Exerc; 32(2):291-6. [accessed October 2021 via: https://pubmed.ncbi.nlm.nih.gov/10694109/]
20. Pline & Smith (2005) “The effect of creatine intake on renal function”. Ann Pharmacother; 39(6):1093-6. [accessed October 2021 via: https://pubmed.ncbi.nlm.nih.gov/15886291/]  
21. Taes et al. (2004) “Creatine supplementation does not decrease total plasma homocysteine in chronic hemodialysis patients”. Kidney Int; ; 66(6):2422-8. [accessed October 2021 via: https://pubmed.ncbi.nlm.nih.gov/15569335/]
22. Gualano et al. (2010) “Effect of short-term high-dose creatine supplementation on measured GFR in a young man with a single kidney”. m J Kidney Disr ;55(3):e7-9. [accessed October 2021 via: https://pubmed.ncbi.nlm.nih.gov/20060630/] 
23. Wallimann et al. (2011) “The creatine kinase system and pleiotropic effects of creatine”. Amino Acids; 40(5):1271-96. [accessed September 2021 via: https://pubmed.ncbi.nlm.nih.gov/21448658/]
24. Sports Dietitians of Australia “Creatine” [accessed September 2021 via: https://www.sportsdietitians.com.au/factsheets/supplements/creatine-athletes/]