does it live up to the hype?

Creatine is the first major fitness supplement I remember everyone talking about. It’s popularity seemed to fade a bit as newer supplements hit the market, but it still remains one of the most widely researched and used supplements in athletes and fitness enthusiasts. So what is it, what does it do, and how can it benefit athletic performance?

What is creatine?

Creatine is a compound that is produced in the body, mainly in the liver and kidneys at about 1 gram per day, with an additional gram per day obtained in the diet, mainly from meat products. Therefore vegetarians and vegans will consume lesser amounts.  The majority of creatine, about 95%, is found in skeletal muscle. About 60% of creatine is stored as creatine phosphate, or phosphocreatine. This form of creatine can quickly provide energy when the phosphate group is transferred to ADP to generate ATP which is the energy source for muscle contraction. Unfortunately, the muscles limited ATP supply is quickly used up, especially during intense exercise, and the need to regenerate ATP is essential for athletic performance. This is especially true in anaerobic conditions when oxygen is not available for complete oxidation of more abundant fuels such as glycogen and fatty acids. 

 

Benefits of Creatine Supplementation

  • Increased strength and power
  • Decreased muscle damage
  • Improved quality of high intensity exercise
  • Improved recovery
  • Increased muscle hydration

 

What does the evidence show?


First off, the number of studies done on creatine supplementation is so abundant it would be nearly impossible to completely review every article in depth. Therefore I have looked at numerous review articles to summarize the findings below, while looking at some of the newer studies in more detail. 

Strength and power

When combined with heavy resistance training, creatine monohydrate supplementation has been shown to enhance physical performance, muscle mass, and fat free mass. Creatine supplementation appears to increase body weight and lean body mass or fat-free mass, but these measurements do not distinguish between muscle growth and increased water content of muscle. Creatine will increase water entry into the cells, and this is at least partially responsible for the weight gain that is seen, especially in the beginning phase of use (1). Double-blind studies using more specific muscle measurements have been done and found that combining creatine supplementation with strength training over several weeks does produce greater increases in muscle size compared with strength training alone by increasing gene expression of factors involved in muscle growth (5). Creatine might also impact cell metabolism by altering cell volume through the above mentioned water entry.

Studies have shown a gender difference in responses to creatine with women typically gaining less body mass than men. However, women seem to receive the same performance benefits from creatine supplementation as men (7).

Improved high intensity performance

As noted, phosphocreatine is used to donate a phosphate group to ADP in order to produce ATP for muscle contraction when oxygen is scarce. It would make sense then that having abundant phosphocreatine stores would allow for quicker replenishment of ATP and improved performance, especially in activities that require explosive bursts of energy and power. There have been numerous double-blind or controlled studies that have found creatine supplementation, typically 15 to 25 grams per day for five or six days in a loading period, improves performance of either single or repetitive bouts of short-duration, high-intensity exercise lasting under 30 seconds each (1-3). Conversely, there have been a smaller amount of studies that did not support these findings. These non-supporting studies have been of small size and have had research design problems, however that does always lend itself to question if the supplement will benefit all athletes. There is also still debate if there is a direct effect on muscle growth, or if supplementation may indirectly allow for improved strength and performance through other mechanisms.

 Based on the mechanism of creatine, it does not appear that this would be a supplement that would aid in endurance activities that are over a few minutes in length. There are studies that have attempted to evaluate this however. One study did show an improvement in lactate threshold, although no improvement in aerobic metabolism (8). Creatine may also help to buffer changes in muscle acidosis, as well as sparing glycogen utilization during short-duration activities. This would allow greater glycogen availability as the activity length increases. Additionally, as noted below, if creatine may benefit in recovery and decreasing muscle damage this would be extremely beneficial in the endurance athlete that sustains a great deal of muscle damage during endurance activities. Also, as I note later in this article, creatine improves muscle hydration which can deter fatigue, cramping, and muscle breakdown which will allow the athlete to perform longer and at a higher intensity.

 

enhanced recovery

Creatine appears to improve recovery between repeated sets of high intensity activity such as repeated sprints or intervals. In addition, there have been findings that creatine supplementation can increase muscle recovery and decrease markers of muscle breakdown after exercise involving eccentric muscle contraction (9).  This is something invaluable in weight lifting, sprint, and endurance sports. Eccentric muscle contraction can be especially damaging to muscles, as seen in downhill running, and to have a way to speed recovery has the potential to improve athletic performance.  However, another study found no benefit to recovery with creatine use (11). The issue is that the latter study only supplemented creatine for 48 hours prior to exercise, while the study showing benefit had a five day loading period. Another negative trial in well-trained athletes performing squat exercises found no benefit to recovery with creatine supplementation (10).

Its hard to compare all of these studies side by side, as some looked at eccentric contraction and others looked at concentric muscle contraction. Also, the study based on eccentric muscle breakdown was done in untrained subjects, while the latter study included well trained athletes. Perhaps then creatine supplementation may be more beneficial to the more novice athlete, and may also depend on the type of exercise being performed.

 

safety

There have been reports of mild adverse reactions to creatine monohydrate, with GI upset being at the top of that list. This is typically seen with those using the loading dose, which can range from 15-25 grams a day for five days based on body weight. This seems to have become less of an issue with improved formulations of creatine monohydrate, and athletes seem to do well with smaller doses throughout the day if they do experience GI upset with the larger doses. 

Another potential negative effect of creatine is kidney or liver damage. As a nephrologist this is something that I have been asked numerous times, and have heard many anecdotal reports. Many may recall news reports of athletes that suffered kidney or muscle damage which was blamed on creatine supplements, however these allegations turned out to be false. One that sticks out is a 2010 report from the New York Times about an Oregon High School football team. Several players were hospitalized for rhabdomyolysis, a syndrome of severe muscle breakdown that can lead to compartment syndrome and kidney failure. Because the marker of muscle breakdown, creatine phosphokinase, is elevated in rhabdomyolysis it was concluded that creatine supplementation was to blame. However, the trigger for rhabdomyolysis is typically intense exercise, dehydration, and intense heat, all of which these athletes were exposed to. The football players also denied taking creatine. It does illustrate how quickly something can become taboo from media influence.

Research on healthy individuals has found no impact of creatine on either kidney or liver function, although individuals with a preexisting condition could potentially have problems. Creatine supplementation will increase creatinine production and excretion which can raise alarm if blood work is done. Creatinine is a marker of muscle mass and breakdown and one of the numbers we use as doctors to evaluate kidney function. High creatinine levels key us in to patients that may be suffering from kidney damage. However, we also know that individuals with greater muscle mass will have naturally higher levels of creatinine based on physiology alone. In healthy individuals, taking creatine monohydrate at the recommended doses will not cause kidney damage. That being said, I would not recommend anyone with preexisting kidney or liver issues to use this supplement based on the potential to aggravate these conditions. 

In the early days of creatine use, there were many anecdotal reports of muscle cramping, but direct research has not supported this effect. Cramps are more likely due to the high-intensity nature of the training being done and/or electrolyte imbalances. Ensuring adequate water and electrolyte intake during creatine loading is a key factor to avoid such problems. One study of collegiate football players found that CM actually decreased the incidence of cramping and injury (12). A well researched review article also showed that creatine has either a neutral or beneficial effect on dehydration risk by increasing water retention, lowering body temperature, and reducing exercising heart rate and sweat rate.  This makes sense as creatine drives water retention which should help deter cramping and dehydration and aid athletic performance.

 

bottom line

Of all the available supplements on the market today, creatine monohydrate is the most widely studied. An abundance of studies do show benefit with supplementation, typically with a loading dose of 15-25 grams a day for about five days followed by a maintenance dose of 5 grams a day. But to be fair, there have been negative studies as well that have not shown benefit. Personally, I do supplement with creatine. Compared to a lot of supplements out there it is one of the most widely studied, cheap, and safe ergogenic aids out there.  I feel that the potential for the benefit in aiding recovery and limiting muscle breakdown while increasing muscle hydration is very helpful in endurance related sports and high intensity activities. Additionally, during weight or HIIT sessions, the ability to rapidly replete ATP stores allows for increased reps and power.  The other big thing to note with all of these trials and findings is that in real life, athletes are not using creatine in isolation. There are many aspects of training, including whole food intake, dietary supplementation, training schedule, sleep schedule, stress levels, and incorporating recovery in between training sessions. Creatine is simply another component that aids in training. It is not a miracle powder. 

This also appears to be a very safe supplement despite some anecdotal reports of health issues that have been reported. As a nephrologist I have specifically seen these cases where it was postulated that creatine supplementation could be responsible for acute kidney failure. It is extremely unlikely that at the recommended doses that this would be an issue in healthy adults. Creatine supplemenation is clearly of most benefit in those doing high intensity, short bursts of activity, such as weight lifting and sprinting. I also see where this could come into play in endurance sports as well when short bursts of energy are called upon for sprints at the end of a bike or long run. Right now I am using IdealFit Creatine supplement at 5 grams a day that I mix with a protein shake after my workouts. You can visit the site and use this 10% off code if you’d like to give it a try! Code: HOLLY-ROQ

References

1. Graef JL, Smith AE, Kendall KL, Fukuda DH, Moon JR, Beck TW, Cramer JT, Stout JR. –  The effects of four weeks of creatine supplementation and high-intensity interval training on cardiorespiratory fitness: a randomized controlled trial . J Int Soc Sports Nutr. 2009 Nov 12;6:18. 

2. Juhász I, Györe I, Csende Z, Rácz L, Tihanyi J. –  Creatine supplementation improves the anaerobic performance of elite junior fin swimmers . Acta Physiol Hung. 2009 Sep;96(3):325-36.

3. Kendall KL, Smith AE, Graef JL, Fukuda DH, Moon JR, Beck TW, Cramer JT, Stout JR. –  Effects of four weeks of high-intensity interval training and creatine supplementation on critical power and anaerobic working capacity in college-aged men . J Strength Cond Res. 2009 Sep;23(6):1663-9. 

4. Casey, A., D. Constanin-Teodosiu, S. Howell, E. Hultman, and P.L. Greenhaff.  Creatine ingestion favorably affects performance and muscle metabolism during maximal exercise in humans . Am. J. Physiol. 271: E31-E37. 1996

5. Willoughby DS and J. Rosene. Effects of oral creatine and resistance training on myosin heavy chain expression. Med Sci Sports Exerc. (2001) 33(10):1674-81.

6. Bemben MG, Lamont HS Creatine supplementation and exercise performance: recent findings. Sports Med. (2005) 35(2):107-25.

7. Branch JD. Effect of creatine supplementation on body composition and performance: a meta-analysis. Int J Sport Nutr Exerc Metab. (2003) 13(2):198-226.

8. Chwalbinska-Moneta J. Effect of creatine supplementation on aerobic performance and anaerobic capacity in elite rowers in the course of endurance training. Int J Sport Nutr Exerc Metab. (2003) 13(2):173-83

9. Matthew B Cooke, Emma Rybalka, Andrew D Williams, Paul J Cribb and Alan Hayes. Creatine supplementation enhances muscle force recovery after eccentrically-induced muscle damage in healthy individualsJournal of the International Society of Sports Nutrition20096:13.

10. Rawson, ES, MP Conti, and MP Miles. Creatine supplementation does not reduce muscle damage or enhance recovery from resistance exercise. Journal of Strength and Conditioning Research, 21(4):1208-1213, 2007.

11. Boychuk KE, Lanovaz JL, Krentz JR, Lishchynsky JT, Candow DG, Farthing JP. Creatine supplementation does not alter neuromuscular recovery after eccentric exercise.Muscle Nerve. 2016 Sep;54(3):487-95. 

12. Greenwood M, Kreider RB, Greenwood L, Byars A. Cramping and Injury Incidence in Collegiate Football Players Are Reduced by Creatine Supplementation. Journal of Athletic Training. 2003;38(3):216-219.

13. Dalbo VJRoberts MDStout JR, et al Putting to rest the myth of creatine supplementation leading to muscle cramps and dehydration.