Note — The majority of the information for this article comes from the International Society of Sports Nutrition’s Position Stand (Kreider, 2017). I added some supplemental citations for interesting points, but if there is a stat or a claim that isn’t referenced then it came from this article. I just didn’t want to cite the same article dozens of times for the sake of readability. There are 269 references in that article, so if you are interested in learning more, I encourage you to read that article.
Creatine is a naturally occurring amino-acid found primarily in red meat and seafood. It is one of the most popular ergogenic  supplements in the world, with reports suggesting up to 40% of athletes use it, though it is much more popular with male strength and power athletes (Knapik, 2016). Previously, professional bodies have 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” (Buford, 2007).
Even though there is a widespread consensus in the scientific community about the potent performance-enhancing effect of creatine, there is still a stigma around its consumption. Many people think it is either unnecessary compared to a proper diet, not fit for younger athletes, in the same class as a steroid, or downright dangerous! This article is going to explore creatine in several ways. We will look at the metabolic role of creatine and what it does in the body. We will examine the performance-enhancing benefits you get from supplementation as well as how to take it. But more importantly, we will determine…is it safe? Are there any side effects? What groups of people should and shouldn’t be using creatine?
So if you’ve ever wondered about creatine, keep on reading.
Creatine Metabolism — How it works and why do we need it?
The vast majority of creatine in the body is located directly in the muscle (~95%). Around two-thirds is in the form of Phosphocreatine (PCr) meaning a creatine molecule is combined with a phosphate molecule, while the rest is freely floating around in the muscle. To understand the role of creatine in the body (and thus, why we need to supplement it) we first need to understand the Anaerobic Energy System.
The Anaerobic system, meaning without Oxygen, is one of our 2 primary energy systems  in the body tasked to create Adenosine Triphosphate (ATP or energy) for any task we need it for. The Anaerobic energy system can be further broken down into 2 other systems, the Phosphocreatine System and the Glycolytic System , and both are used to create ATP when we need it quickly. The PCr system (or Alactic System) is the one we are concerned with when we are discussing Creatine. This energy pathway creates a whole bunch of ATP in an extremely short period of time (i.e., several seconds) and usually needs several minutes of rest to completely recover before it can go flat out again. This is why this energy system is primarily used during high powered events like sprinting or a max squat. Now that we know what the PCr energy system is, let’s talk about how creatine fits into the picture.
When you want to contract your muscles, you need the energy stored in ATP to power that contraction. When you do something explosive, you need a lot more ATP in a very short period of time. To get the energy out of an ATP molecule to be used by your muscles, it has to lose a phosphate molecule (tri-phosphate, meaning it has 3 phosphates to begin with). This removal of a phosphate group results in some energy we can use to power our muscles but leaves us with Adenosine Diphosphate (ADP, 2 phosphates) and a molecule of phosphate floating around (ATP → ADP + Phosphate ion + energy).
To keep contracting our muscles, we need more ATP but now we only have a bunch of useless ADP floating around. This is where creatine comes in. To ensure we have a steady supply of ATP, the PCr that we had previously stored in our muscles is immediately broken down so that the phosphate molecule leaves the creatine molecule and combines with the lonely ADP to recreate a new ATP molecule (PCr + ADP → ATP + Creatine). This newly formed ATP molecule can then be used again as energy for the muscle. When we have some time to rest (like after our 100m race), our cells then resynthesizes PCr by recombining the creatine and phosphate molecules that are floating around (P + Cr → PCr). Since we only have a small amount of PCr in our muscles, this energy system is quite short and runs out extremely quickly (between 5–10 seconds) causing us to rely on our other energy systems to pick up the slack (this will be a future article series!).
TL;DR: Creatine, in the form of PCr, is used in the process of providing massive amounts of energy during short-term (<10 seconds) high-powered events.
Knowing that the creatine stored in our muscles is used to create energy for high-intensity situations, we have a better idea of why supplementing it could be of use to an athlete. The actual amount of creatine we store in our bodies is dependent on many things and is highly individual. So for discussion purposes, a 70kg person generally stores around 120mmol of creatine per kilogram of dry muscle mass if no supplementation is used. We need about 1–3g of creatine per day to maintain normal (unsupplemented) levels, where about half comes from our diet (i.e., red meat and seafoods) while the other half is created in the liver and kidneys from other freely floating amino acids.
However, the upper limit of creatine our hypothetical 70kg person could potentially store is somewhere around 160mmol/kg. These numbers don’t exactly matter, but the point is that if you don’t supplement with creatine, you won’t have as much creatine in your body, therefore, you won’t have as much PCr directly on your muscles. Remember, PCr is used to create the energy needed for explosive movements, so the more of it we have the more ATP we can create, and thus, the more power we can produce.
TL;DR: Creatine supplementation increases the amount of creatine our body stores, thus increasing our concentration of PCr to be directly used for ATP creation.
What are the benefits?
Now that we know what creatine is and its role in the body, why should you consider supplementing it? What benefits can it give an athlete?
Since creatine supplementation increases the total amount of PCr available, it helps to enhance short term exercise capacity in high powered events like sprinting, lifting, jumping and throwing (or anything that requires strength and power). It has been shown to do this in adolescents, young adults, and older individuals. This increase in energy availability allows those who supplement it an increased ability to do more work (e.g., more sets or days of training) or more intense training (e.g., heavier weights or faster sprints) thus leading to improvements in strength, muscle mass, and sports performance. Said another way, creatine supplementation causes an improvement in the Quality of Training an athlete can perform which leads to better performance adaptations. This is why the vast majority of creatine research shows performance improvements around 5–15% in high intensity or repetitive events (Kreider, 2003).
The following are some of the various performance-enhancing effects of creatine:
- Higher single repetition strength/power outputs.
- Important for 60–200m sprints, jumping, maximal lifting, etc.
Increased PCr Resynthesis
- Better repeatability and quality of strength/power outputs.
- Important in repeated sprint/power sports like football, soccer, tennis, etc.
Reduced Muscle Acidosis
- If you can get more energy from the PCr system, less energy needs to be derived from Glycolysis thus less lactate and Hydrogen ions are created (this is what causes fatigue in the muscles) and thus you fatigue less quickly (Oliver, 2013).
- Important in hard endurance sports like MMA, 400m sprints or downhill skiing.
Increased Oxidative Metabolism
- Greater shuttling of ATP from mitochondria, meaning we get more ATP out of our aerobic energy system.
- Important in repeated sprint/power sports like soccer, basketball, or during interval training.
Increased Body Mass/Muscle Mass & Strength Adaptations
- If we can train harder with heavier weights you will be able to increase your muscle mass and strength to a greater degree.
- Important in sports like football, rugby, throwing events, etc.
What other benefits are there?
Post-training, the body needs to recover by replenishing its muscle’s primary source of energy, glycogen (i.e., glucose, or sugar stored on the muscle). Creatine, when taken together with a source of glucose, has been found to enhance glycogen replenishment, which could be useful for athletes with a high training volume or intense competition schedule. Other research has found creatine supplementation can reduce muscle damage from intense training by decreasing the amount of inflammation incurred, helping athletes tolerate more training. This means creatine can help athletes tolerate and recover from higher volumes of training due to better glycogen replenishment and less inflammation.
Researchers have found creatine users experience less incidence of cramping, heat illness, dehydration, muscle tightness, muscle strains/pulls, non-contact injuries, and total injuries/missed practices compared to those not taking creatine (Greenwood, 2003). One of the reasons proposed for this phenomenon may be related to creatine allowing athletes to tolerate more training thereby lessening their chance for injury (i.e., more resilient athletes). Despite what you may hear, creatine has not been linked to short term or long term injury development in athletes (studies have followed athletes for 3 years for example), where the evidence to the contrary (i.e., fewer injuries) definitely exists.
Enhanced Rehabilitation from Injury
Since creatine can improve strength and therefore increase muscle mass, there is an interest in its role for reducing muscle atrophy post-injury. Research has found creatine supplementation can help increase muscle gain and strength improvements at a quicker rate during the rehabilitation process (Heslep, 2001). This is most likely because the increase in muscle PCr helps to increase strength output and improve tolerance to training during the rehab process, leading to better outcomes.
Better Tolerance to Exercising in the Heat
Creatine has osmotic properties, meaning it retains a little bit of water when its levels increase in the body, somewhere in the neighborhood of 0.5L-1.0L of fluid. This extra water may help to hyper-hydrate an athlete, leading to an increased tolerance to training in the heat, thereby reducing the risk of heat-related illnesses (Dalbo, 2008).
Brain and Spinal Cord Neuroprotection
Far beyond the scope of this article to explore in-depth, but it is worth noting creatine supplementation has neuroprotective effects due to its ability to combat oxidative stress and other toxins in the brain (Beal, 2011; Bender, 2016). This is likely why research has found creatine supplementation can decrease the damage associated with Traumatic Brain Injuries and Spinal Cord Injuries. Such information is particularly important for any athlete, but especially those in contact sports where the risk of concussion damage is very real. This is because brain concentrations of creatine decrease after a concussion, and why creatine supplementation has been shown to increase cognition and decrease symptoms in children who sustained moderate to severe concussions (Ashbaugh, 2016).
Note — This is not to suggest creatine can prevent a concussion!
Other Medical Benefits?
Creatine Synthesis Deficiencies
Neurodegenerative Diseases (i.e., Parkinson Disease)
- Can increase work capacity and clinical outcomes.
Ischemic Heart Disease
- Can protect the heart from further damage in the case of a heart attack.
- Can improve health status and functional capacity as people age.
- Potential benefits on fetal growth and development.
How to Take?
Now that we know creatine is extremely potent for improving an athlete’s performance, as well as a whole host of other benefits, the question is, what type of creatine should you be taking and how do you take it?
The most studied form of creatine is Creatine Monohydrate, which means the benefits we talked about previously are easily obtained with this form. It’s cheap, fast-acting (takes about 60min post-ingestion to maximize plasma levels), and easy to find. Other forms of creatine that are marketed as better for improving muscle creatine content are unfounded and not supported by the research. Just ensure you get a brand that is approved for sport and you will be fine.
People who do not supplement have muscle creatine stores of around 60–80% saturation, which is why supplementation has been shown to increase creatine and muscle PCr stores by 20–40%. An interesting aside is that vegetarians generally have lower creatine stores due to the lack of creatine in their diet, and therefore may experience a greater than 40% increase in creatine content. This shows that individuals will not maximize their PCr levels with diet alone, and regular supplementation is recommended for athletes.
Once you have some creatine monohydrate, there are 2 ways you can take it. Method 1, or the loading method, is to consume 5g four times per day (20g total) for about 5–7 days (or ~0.3g/kg total per day). This loading block fully saturates your creatine stores, and you will need to maintain these levels by consuming 3–5g daily to preserve the performance benefits. Method 2 is more gradual, and consists of you ingesting 3–5g daily from the beginning and takes around 28 days to fully saturate your levels (again you will need to continue with 3–5g per day to keep the benefits). Neither way is necessarily better, but if you are in need of the ergogenic benefits sooner, Method 1 may be the way to go. However, I generally recommend Method 2 as it is simpler (i.e., 5g per day forever).
Once you have elevated your stores (i.e., either after 5 or 28 days), you must continue supplementation or else you will lose the benefits you gained. Research suggests you will return to your baseline levels after about 4–6 weeks of ceasing supplementation, so it’s not immediate but will happen. There is also no evidence that your baseline levels will decrease further after you stop supplementing, as well as no evidence that your body will decrease its natural production. So you don’t need to worry that you are impairing your natural creatine development or storage.
TL;DR: You can take creatine monohydrate 2 ways. The quickest, Method 1, is 20g daily for 5–7 days followed by 3–5g daily thereafter. Method 2 is 3–5g daily and takes roughly a month to saturate your creatine levels.
Is it safe though?
Creatine has been extensively used for over 30 years, with well over 1000 studies examining its efficacy and safety. It is by far the most studied supplement on the market, but due to its popularity, it also has its share of bad press. Often the majority of the negative attention comes from anecdotal media coverage, sensationalized case reports, or Karen from book club telling you her opinion on creatine. Fortunately, these claims do not hold water when rigorous and well-designed clinical trials show that creatine supplementation does not increase the incidence of any type of adverse effect.
To quote Kreiders 2017 review paper on creatine;
“[the] available short and long-term studies in healthy and diseased populations, from infants to the elderly, at dosages ranging from 0.3 to 0.8 g/kg/day for up to 5 years have consistently shown that creatine supplementation poses no adverse health risks and may provide a number of health and performance benefits”.
Said plainly, CREATINE IS NOT DANGEROUS. Creatine has been studied in children, old people, athletes, non-athletes, pregnant ladies, people with serious health conditions, as well as used with extremely high doses for many years, and time and time again no adverse health risks have been found. The only real concern is if you take too much at one time which may cause gastric distress (i.e., stomach ache), so in that case, split up your dose evenly throughout the day.
In comparison, over 80% of NCAA athletes consume alcohol while 10–16% use tobacco. Both of these substances have well known adverse effects, yet are more socially acceptable (especially alcohol) among athletes and have less of a stigma than creatine (well..maybe not tobacco, but e-cigarettes are becoming extremely popular). Especially with the reported performance and health benefits associated with creatine, perhaps more education pertaining to this supplement is warranted. Individuals should feel very comfortable in taking this supplement, and it has even been recommended that most people should supplement it regularly to promote general health (Wallimann, 2011), regardless if they are an athlete or not.
One safety concern that is worth addressing is creatine’s effect on kidney function. Initial reports showed people who took creatine showed greater levels of creatinine in the urine, which is a marker of poor kidney function, and raised some concerns about creatine’s safety. However, creatinine is the metabolic byproduct of creatine and around 1–2% of our body’s creatine is broken down into creatinine every day. So if you supplement and increase your body’s stores of creatine…you will break down more of it and thus excrete more creatinine. This gives you a false positive, when in fact your kidneys are working just fine. This is why a large body of research has concluded that there is no compelling evidence that creatine supplementation impairs kidney function in healthy and clinical populations (for example; Poortmans, 1999).
Hopefully, this article on creatine was enlightening and informative. My goal was to give a bit more substance and background than simply regurgitating “Creatine is safe and makes you more powerful!”. We explored the role of creatine in the body and its purpose in energy production. We realized that our creatine stores can only reach maximal limits with supplementation rather than naturally from our diet. Besides improvements in power and strength, we highlighted many areas creatine can be useful like in rehab, brain health, and other medical conditions. Finally, we discussed how creatine is extremely safe, at any age, in any demographic.
Now…go buy some creatine monohydrate and reap the rewards!
 Intended to enhance physical performance, stamina, or recovery.
 The 2 main energy systems in our body are the Anaerobic Energy System and the Aerobic Energy System.
 Also termed the Lactic Energy System. This is the energy pathway that creates Lactate and Hydrogen ions (H+). The H+ are what cause the burning feeling in your muscles and why you fatigue during hard exercise.