Creatine

Creatine

Creatine is one of the most popular and widely researched supplements used by athletes to increase muscle mass, improve high-intensity exercise performance, and aid in recovery. In this article, I will discuss what creatine is, what it does in your body, and what the current literature suggests in terms of safety and usage. From there, my hope is that this conversation sparks a desire to continue to research the topic on your own so that you can make an informed decision on whether or not this supplement is right for you. 

*** Disclaimer: The information in this article is not intended to serve as medical advice. Please consult with your medical provider(s) (and parents, if applicable) before taking this or any supplement. 

 

WHAT IS CREATINE?

Creatine (methyl-guanidine-acetic acid) is a non-protein amino acid compound that is naturally produced within the body at a rate of approximately 1g/day. (1) Synthesis occurs primarily in the liver and kidneys, and to a lesser degree, in the pancreas. (2) Aside from being produced within the body, creatine can also be consumed by eating red meat and seafood, as well as through oral supplementation. In addition to its performance related benefits, a number of clinical applications have been studied in neurodegenerative disease populations such as Muscular Dystrophy, Parkinson’s, Huntington’s Disease, and Fibromyalgia.

 

WHAT DOES CREATINE DO IN THE BODY?

About 95% of creatine in our body is stored in skeletal muscle. Creatine by itself does not provide much use, but when it is converted to Phosphocreatine (PCr) via the enzyme Creatine Kinase (CK), it essentially serves as an energy reservoir. Here's how... 

During high intensity exercise, our skeletal muscles often require more ATP than our mitochondria are capable of producing. This is where the Phosphocreatine Shuttle System comes into play and why creatine supplementation can help improve high intensity exercise performance. 


Image: The phosphocreatine shuttle system

  • Step 1: ATP is produced in the mitochondria. It then reacts with CK to create PCr which moves into the sarcoplasm for use.
  • Step 2: Once PCr is in the sarcoplasm, it reacts with more CK, converting PCr back to Cr and giving a high energy phosphate to ADP in the process. ADP is converted back to ATP which can then be used to provide energy to the muscle cell. 

By supplementing creatine, you increase your CK stores and allow for more "substrate" to be available for both reactions. This results in shorter recovery times and a greater ability to sustain high intensity activity.

 

IS IT SAFE?

Since creatine monohydrate became a popular dietary supplement in the early 1990’s, over 1,000 studies have been conducted on its effects. The only consistently reported side effect of creatine supplementation described in the literature has been weight gain. (1,8,10,11,13,14)

On the topic of whether or not creatine has negative effects on renal (kidney) function, studies have reported that ingesting up to 10g/day from 10 months to 5 years had no effect on creatine clearance, glomerular filtration rate, tubular resorption, or glomerular membrane permeability compared to controls. (15) Kreider et al reported that creatine supplementation (5-10g/day for 21 months) had no significant effects on creatinine clearance in American football players. (8) Gualono et al reported that 12 weeks of creatine supplementation had no effects on kidney function in type 2 diabetic patients. (16) No current evidence exists to support the notion that creatine supplementation negatively affects renal function in healthy or clinical populations. (8,11,15,17,18)

In response to critics of creatine supplementation who advise individuals younger than 18 years of age to avoid taking creatine due to safety concerns, it is important to recognize that this is a legal precaution, and that as of today, there is no scientific evidence that supports that children and/or adolescents should not take creatine due to safety concerns. According to the ISSN, creatine supplementation is an acceptable nutritional strategy for younger athletes who are:

  1. Involved in serious, competitive, and supervised training
  2. Are consuming a well-balanced diet
  3. Are knowledgeable about the appropriate use of creatine
  4. Do not exceed recommended dosages. 

 

SUPPLEMENTATION PROTOCOLS 

In a normal diet that contains 1-2g/day of creatine, muscle creatine stores are about 60-80% saturated. (1) Therefore supplementation of creatine serves to increase muscle creatine and PCr levels by 20-40% (to 100%). The most effective way to increase muscle creatine stores is to ingest approximately 0.3g/kg/day of creatine monohydrate split between 4-5 servings daily for 5-7 days. (3,4) This is called the “pre-load” stage. However, higher creatine loads may be needed: a.) for larger individuals, b.) to offset endogenous creatine synthesis deficiencies, or c.) to influence disease states. (5,6,7) Once creatine stores are fully saturated, a “maintenance” dosage of 3-5g/day (or 5-10g/day for larger athletes) will help to maintain creatine stores. (3,4) No evidence has suggested that muscle creatine levels fall below baseline after cessation of creatine supplementation. Said otherwise, suppression of endogenous creatine synthesis does not seem to occur despite supplementation. (8,9). 

 

PERFORMANCE BENEFITS 

Creatine supplementation has primarily been recommended as a performance aid for power/strength athletes to help them optimize training adaptations or athletes who need to sprint intermittently and recover during competition (ie: American football, basketball, tennis, soccer, etc). After creatine loading, performance of high intensity and/or repetitive exercise is generally increased by 10-20% depending on the magnitude of increase in muscle PCr. (10) In terms of performance, the International Society of Sports Nutrition (ISSN) has previously concluded that creatine monohydrate is the most effective ergogenic nutritional supplement currently available to athletes in terms of increasing high-intensity exercise capacity and lean body mass during training. (11,12) Recent position stands by the American Dietetic Association, Dietitians of Canada, and the American College of Sports Medicine on nutrition for athletic performance all drew similar conclusions. (13,14) 


SUMMARY

  • Creatine monohydrate is the most effective ergogenic nutritional supplement currently available to athletes with the intent of increasing high intensity exercise capacity and lean body mass during training.
  • Creatine monohydrate supplementation is not only safe, but has been reported to have a number of therapeutic benefits in healthy and diseased populations from infants to the elderly. 
  • Label advisories on creatine products that caution against usage by individuals under 18 years of age, while perhaps intended to avoid legal liability, are likely unnecessary given the scientific evidence supporting creatine’s safety in children and adolescents. 
  • At present, creatine monohydrate is the most extensively studied and clinically effective form of creatine for use in nutritional supplementation. 

Given the volume of evidence supporting the efficacy and safety of creatine monohydrate supplementation, I recommend it to most of my athletes looking to improve their strength and power. However, as with anything you put into your body, I encourage you to do your own research and first consult with your healthcare provider(s) prior to including it into your diet . Regardless of how much you respect my opinion, I am not the one performing the studies. Check out the studies I referenced in this article below for more information. 

 

REFERENCES

  1. Kreider, R.B.; Kalman, D.S.; Antonio, J.; Ziegenfuss, T.N.; Wildman, R.; Collins, R.; Candow, D.G.; Kleiner, S.M.; Almada, A.L.; Lopez, H.L. International Society of Sports Nutrition position stand: Safety and efficacy of creatine supplementation in exercise, sport, and medicine. J. Int. Soc. Sports Nutr. 2017, 14, 18. 
  2. Cooper, R; Naclerio, F; Allgrove, J; Jimenez, A. Creatine supplementation with specific view to exercise/sports performance: an update. Journal of the International Society of Sports Nutrition. 2012, 9, 33. 1-11. 
  3. Hultman E, et al. Muscle creatine loading in men. J Appl Physiol (1985). 1996;81(1):232–7
  4. Harris RC, Soderlund K, Hultman E. Elevation of creatine in resting and exercised muscle of normal subjects by creatine supplementation. Clin Sci (Lond). 1992;83(3):367–74.
  5. Braissant O, et al. Creatine deficiency syndromes and the importance of creatine synthesis in the brain. Amino Acids. 2011;40(5):1315–24
  6. Hanna-El-Daher L, Braissant O. Creatine synthesis and exchanges between brain cells: what can be learned from human creatine deficiencies and various experimental models? Amino Acids. 2016;48(8):1877–95.
  7. Bender A, Klopstock T. Creatine for neuroprotection in neurodegenerative disease: end of story? Amino Acids. 2016;48(8):1929–40.
  8. Kreider RB, et al. Long-term creatine supplementation does not significantly affect clinical markers of health in athletes. Mol Cell Biochem. 2003;244(1–2): 95–104
  9. Kim HJ, et al. Studies on the safety of creatine supplementation. Amino Acids. 2011;40(5):1409–18.
  10. Kreider RB. Effects of creatine supplementation on performance and training adaptations. Mol Cell Biochem. 2003;244(1–2):89–94
  11. Buford TW, et al. International Society of Sports Nutrition position stand: creatine supplementation and exercise. J Int Soc Sports Nutr. 2007;4:6.
  12. Kreider RB, et al. ISSN exercise & sport nutrition review: research & recommendations. J Int Soc Sports Nutr. 2010;7:7.
  13. Rodriguez NR, et al. Position of the American Dietetic Association, dietitians of Canada, and the American college of sports medicine: nutrition and athletic performance. J Am Diet Assoc. 2009;109(3):509–27.
  14. Thomas DT, Erdman KA, Burke LM. Position of the academy of nutrition and dietetics, dietitians of Canada, and the American college of sports medicine: nutrition and athletic performance. J Acad Nutr Diet. 2016;116(3):501–28.
  15. Poortmans JR, Francaux M. Long-term oral creatine supplementation does not impair renal function in healthy athletes. Med Sci Sports Exerc. 1999;31(8):1108–10.
  16. Gualano B, et al. Creatine supplementation does not impair kidney function in type 2 diabetic patients: a randomized, double-blind, placebo-controlled, clinical trial. Eur J Appl Physiol. 2011;111(5):749–56.
  17. Pline KA, Smith CL. The effect of creatine intake on renal function. Ann Pharmacother. 2005;39(6):1093–6.
  18. Persky AM, Rawson ES. Safety of creatine supplementation. Subcell Biochem. 2007;46:275–89.
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