Long associated with weight rooms and bulking, creatine is making a dramatic entrance into the world of endurance sports. Running, trail running, cycling, triathlon: more and more athletes are incorporating it into their sports nutrition routine.
Is it really useful when you are clocking up the miles? How can you take it without risking getting “bloated”? I have run the Mulebar store since 2008 and prepared this guide to help you see things clearly: what creatine really does for an endurance athlete, how much to take, and how to choose it properly.
To make this guide easy to read in one sitting, I explain each technical term when it first appears. The studies and official texts are cited throughout the article and collected at the end for anyone who wants to verify them.
What is creatine?
Creatine is a nitrogen-containing molecule, meaning a molecule that contains nitrogen, naturally produced by the liver, kidneys, and pancreas. The body assembles it from three amino acids, the building blocks of proteins: glycine, arginine, and methionine. It also comes from food, especially meat and fish, at a rate of about 1 to 2 g per day in an omnivorous diet (Kreider et al., 2017).
Biological role
It is stored 95% in the muscles, in the form of phosphocreatine: creatine with a phosphate group attached. Imagine a charged battery stored directly in the muscle fiber, ready to discharge at the first contraction.
This battery is used to regenerate ATP (adenosine triphosphate), the energy currency of every cell in the body. Every muscle contraction consumes ATP; phosphocreatine gives it its phosphate back in a fraction of a second to recharge it. This is the fastest energy source available to the muscle, but also the most limited: it covers a few seconds of maximal effort (a sprint, a deadlift, a weight-training set), then it must be replenished.
Effect of supplementation
Taken as a dietary supplement, creatine saturates muscle stores beyond what the diet can provide: stores increase by 20 to 40% (Kreider et al., 2017). In other words, the battery is bigger and recharges faster. In practical terms, this:
- Increases the ability to repeat explosive efforts
- Promotes muscle mass gain (through training and slight water retention inside the cell)
- Has shown preliminary cognitive effects (memory, mental fatigue), which are still being studied
On this last point, “preliminary” means that studies exist but remain few and small: it is an interesting avenue, not a promise. The brain also consumes ATP, hence the researchers’ interest.
Creatine for endurance: myth or true ally?
Three questions constantly come up among runners, trail runners, cyclists, and triathletes: does it work, is it useful for endurance, and does it cause weight gain? Here is what the research says, point by point.
Is it really effective, or is it a myth?
Creatine is one of the most studied dietary supplements in the world, with more than 1,000 scientific studies to its name. This is the finding of the ISSN (International Society of Sports Nutrition), the international scholarly society for sports nutrition, in its 2017 “position stand”: a document in which independent researchers review all the published studies to draw sound conclusions (Kreider et al., 2017). Its effectiveness in regenerating ATP has been scientifically proven. This is by no means a myth: it improves energy availability during repeated and sustained efforts.
It is even one of the few supplements whose effects are officially recognized under European regulations. The EFSA (European Food Safety Authority) is the body that verifies the evidence before a brand is allowed to state a health benefit on packaging. For creatine, it approved the claim “creatine improves physical performance in successive bursts of short-term, high-intensity exercise”, at 3g per day or more (EU Regulation 432/2012). Few supplements can say the same.
Is it useful for running, cycling, and cardio?
This is where many endurance athletes struggle. The body produces energy through three pathways, three routes that take turns depending on the duration and intensity of the effort: the phosphocreatine pathway for the first few seconds, the oxygen-free sugar pathway for one to two minutes of very intense effort, and the aerobic pathway, which burns carbohydrates and fats with oxygen and fuels efforts lasting several hours. Distance running, road cycling, and long-distance triathlon rely on this third pathway, which does not use phosphocreatine.
Recent meta-analyses, studies that combine the results of all existing studies on a question to identify a reliable trend, confirm that creatine does not directly improve pure endurance or VO2max, the maximum amount of oxygen the body can use per minute, the “engine” of endurance (Fernández-Landa et al., 2023; Gras et al., 2021). It is not a long-duration race fuel.
However, several mechanisms explain why it remains relevant for an endurance athlete (Forbes et al., 2023):
- The battery recharges during the easy phases: about half in 30 seconds, and almost all of it in 3 to 5 minutes (Harris et al., 1976). During intermittent efforts (interval training, pace changes, uphill surges), these stores are continuously used and replenished, and larger stores make a difference.
- Final sprint and surges: attacks in cycling, climbing hills in trail running, finishing sprint. These are short, intense efforts inserted into a long effort, so they fall squarely within creatine’s area of action.
- Recovery and glycogen replenishment: glycogen is the form in which your muscles and liver store sugars, your main reserve for endurance. Taken with carbohydrates after exercise, creatine may speed up the refilling of this reserve and limit catabolism, meaning the breakdown of muscle when the body draws on its own proteins (Kreider et al., 2017).
- Central fatigue: this is fatigue that comes from the brain rather than the muscles, causing alertness and motivation to decline toward the end of an event. The brain also uses phosphocreatine; preliminary research suggests an effect, but these results remain to be confirmed.
In summary: creatine is not an endurance fuel, but a support tool for intermittent efforts, recovery, and maintaining muscle mass during a season of high training load. Useful, but not essential for a pure “low-intensity base endurance” profile.
Does creatine make you gain weight or get fat?
This is the number one concern among runners and cyclists. The answer is clear: creatine does not cause fat gain. It can lead to a slight weight gain at first (between 0.5 kg and 1.5 kg), but this change is due to water retention (Kreider et al., 2017).
The mechanism is simple: creatine draws water with it into the muscle cell. This gain appears during the first few weeks, while the stores fill up, and then stabilizes: once the stores are full, weight no longer changes. There is no continuous weight gain.
Is it water or muscle?
This is intracellular water retention, meaning inside the muscle cell. It has nothing to do with the water retention under the skin that makes the legs or face look “puffy.” Your muscles do not look swollen or fatty: they are better hydrated.
For an endurance athlete, this cellular hydration even provides a thermal and metabolic advantage, particularly during events in hot conditions: a better-hydrated cell handles heat better. A review of studies on this point found no impairment of heat tolerance or hydration in supplemented athletes (Lopez et al., 2009).
Dosage: how should you take creatine?
Good news: the protocol is one of the simplest in sports nutrition. A small dose every day, and that's it. Here are the answers to the four practical questions that come up most often.
How many grams per day should you take?
The recommended daily dose for an athlete is 3 to 5g per day. This is the ideal dosage for maintaining saturated muscle stores day after day, and it is also the reference dose adopted by European regulations for its official claim (3g per day, EU Regulation 432/2012).
Why this range and not more? Because beyond what the muscles can store, the excess is simply eliminated in the urine after being converted into creatinine, a waste product with no performance benefit (Kreider et al., 2017). Taking 10g instead of 5g doesn't fill the tank any further; it just fills the toilet.
Is a loading phase necessary?
No, it is not necessary. The loading phase (which involves taking 20g per day for 5 to 7 days) saturates the muscles a little faster, but it frequently causes digestive discomfort. “Saturating” means filling the muscle stores to their maximum.
By simply taking 3 to 5g per day, your stores will be fully saturated after 3 to 4 weeks, smoothly and without side effects (Hultman et al., 1996). The final result is the same: only the filling speed changes, and the slower version is more comfortable.
When and how should you take creatine (before or after training)?
Creatine works by building up: consistency matters far more than the exact timing of intake (Kreider et al., 2017). It has no immediate “kick” effect: taking it just before a session makes no difference to that session. What matters is the level in the reservoir, not the time you fill it up.
In her article Creatine in Cycling and Triathlon: The Complete Guide, Ingrid Gallerini, a sports dietitian-nutritionist, advises against starting a creatine protocol within the 3 or 4 weeks before a competition. “It is better to start at the beginning of the build block, during the general preparation phase, when the performance-to-weight ratio is not yet critical,” she recommends.
The most opportune time is immediately after training.
- Absorption is optimized when it is consumed with a source of carbohydrates and protein (for example, in your recovery drink or alongside an energy bar).
- Carbohydrates trigger the release of insulin, the hormone that opens the cells' doors to nutrients after a meal. It also helps transport creatine to muscle cells.
- Avoid: Taking it just before exercise, as it has no immediate boosting effect and may draw water into the stomach during exercise.
Should you take it on rest days?
Yes. Creatine works by building up in the body, not as a one-off stimulant. It is essential to continue taking 3 to 5g on rest days, ideally in the morning with breakfast, to keep your stores at optimal levels.
The reason: every day, the body naturally breaks down 1 to 2% of its creatine stores, which it eliminates as creatinine (Kreider et al., 2017). The daily dose serves to compensate for this loss. Missing one day is not serious; missing several in a row causes the level to gradually fall.
Safety and health
Creatine has been surrounded by a few persistent myths about the kidneys, doping, and long-term effects. Here they are examined against the evidence from studies, without beating around the bush.
How is it made?
High-quality creatine monohydrate is produced through clean laboratory synthesis from two simple chemical components: cyanamide and sarcosinate. Combined under controlled conditions, they form exactly the same molecule as the one found in a steak or a fish fillet. No animal tissue is used in this process: pure creatine is therefore 100% vegan.
The word “monohydrate” refers to the form of the powder: each creatine molecule is bonded to a water molecule, making it stable and easy to store. It is the form used in nearly all scientific studies, and therefore the one whose effects and safety are best understood.
Is creatine dangerous for the kidneys?
In a healthy person with properly functioning kidneys, creatine poses no danger to the kidneys (Poortmans et Francaux, 2000). Studies conducted over several years have shown no impairment of kidney function.
Where does the confusion come from? From creatinine, the waste product produced when creatine breaks down. Doctors measure creatinine in the blood to assess kidney function: when it rises, it is often a sign that the kidneys are filtering less effectively. However, someone who takes creatine naturally produces more creatinine, without their kidneys functioning less well. A slightly elevated level in an athlete taking supplements is therefore a normal physiological consequence, not a sign of disease. If you have existing kidney disease, ask your doctor for advice before taking any supplements.
Are there any side effects?
When consumed at the recommended doses, creatine is extremely well tolerated (Kreider et al., 2017). Minor digestive issues (stomach cramps, diarrhea) only occur if it is ingested in too large a quantity at once or with insufficient water.
In practice, two simple habits are enough: dilute it in a large glass of water or in your drink, and stick to 3 to 5 g per serving. If you have a sensitive stomach, taking it after your workout, when you are eating anyway, is the most comfortable option.
Can it be taken long term?
Yes. Research protocols have examined continuous use for more than 5 years without noting any harmful effects (Kreider et al., 2017). There is therefore no need to take “cycles” or breaks.
A question comes up often: does the body stop producing it? During supplementation, it does produce slightly less because it receives it from an external source. Once supplementation stops, natural production resumes normally and muscle stores return to their starting level within 4 to 6 weeks (Kreider et al., 2017). Nothing is broken, and nothing is lost.
Is it a performance-enhancing drug?
Absolutely not. Creatine is a nutrient naturally present in food (meat and fish) and synthesized by the body. It is not included on the World Anti-Doping Agency's list of prohibited substances, the international organization that publishes the list of substances and methods prohibited in competition each year (2026 list).
It is also classified in Group A of the Australian Institute of Sport (AIS) supplement framework, a globally recognized reference that classifies supplements into four groups, from A to D, according to the level of scientific evidence. Group A includes supplements with strong evidence for defined sports uses (AIS Sports Supplement Framework). Creatine is listed alongside caffeine and sports drinks.
Choosing the right creatine
Not all creatine products are equal, but the criteria that really matter come down to three questions: the form, the format, and the purity.
What is the best form (monohydrate vs. other forms)?
Creatine monohydrate is the gold standard. It is the most extensively studied, best absorbed, and most affordable form (Kreider et al., 2017).
Other market variants (creatine HCL, ethyl ester, buffered, or liquid) promise better absorption or less water retention. They are often more expensive and have never demonstrated any superior effectiveness in independent studies. Monohydrate remains the safest and most logical choice.
Powder or capsules: what is the difference?
It is simply a matter of convenience:
- Powder: the most economical form and easy to mix into your recovery shake or smoothie.
- Capsules: convenient when traveling, competing, or attending training camps.
|
Criterion |
Creatine powder |
Creatine capsules |
|
Convenience |
Mix into a drink |
Easy to carry anywhere |
|
Cost per dose |
Very economical |
Higher |
|
Absorption |
Identical |
Identical |
At an equivalent dosage, the effectiveness remains exactly the same. Choose the format you will actually take every day: that is the only criterion that matters.
Should you choose one with a label?
Yes, it is essential. A purity label is a trademark registered by the raw material manufacturer: it guarantees a precise manufacturing process, checks at every stage, and batch traceability. In plain terms, it guarantees what the sachet really contains.
The historic benchmark label is Creapure®, manufactured in Germany: guaranteed purity of at least 99.9%, impeccable traceability, and closed production lines (Creapure, quality information).
For Mulebar creatine, I chose the Clonapure® label. Its distinctive feature can be summed up in one sentence: instead of providing only creatine monohydrate, it combines creatine monohydrate, phosphocreatine, and calcium phosphate in a single formula. As you read above, phosphocreatine is precisely the “fully charged battery” form that your muscles use to regenerate ATP: the manufacturer therefore claims to deliver the ready-to-use form of muscular energy directly, without waiting for the body to carry out the conversion. Clonapure® is developed and manufactured in Spain by the Tradichem group under EU-GMP conditions, the European pharmaceutical good manufacturing practices and the level of standards applied to medicines. And, as with any creatine, a simple intake of 3 to 5g per day is sufficient, with no loading phase.
Why should you avoid low-grade Chinese creatine?
Some low-cost creatine imported from Asia is produced using less controlled synthesis processes. The problem is not the creatine itself, but what remains alongside it: manufacturing residues, the by-products of the chemical reaction that a well-controlled process removes and a poorly executed process leaves in the powder.
An independent analysis of 33 commercially available creatine products found these by-products in some of the samples: dicyandiamide (DCD), dihydrotriazine (DHT), as well as traces of heavy metals, with the highest levels found in entry-level products (Moret et al., 2011). By comparison, the German Creapure® process claims undetectable DHT and DCD levels well below European limits. For your health and peace of mind, always choose certified creatine manufactured in Europe with a recognized purity label.
Who is creatine for?
Long associated in the public imagination with young men in weight rooms, creatine is actually relevant to a much broader audience. Three cases deserve a precise answer.
Can women take it?
Yes, and they have everything to gain. Women naturally have slightly lower creatine stores than men (Smith-Ryan et al., 2021). Supplementation helps them preserve muscle mass and improve recovery after demanding running or cycling sessions. The dose is the same: 3 to 5 g per day.
Studies are also exploring its potential benefits for bone health after menopause, alongside resistance training; these findings remain to be confirmed. To learn more about the specific needs of female athletes, see the guide to sports nutrition for women.
At what age can you take it?
Creatine is recommended for adult athletes aged 18 and over. It is particularly beneficial for athletes over 40 or 50 to help combat sarcopenia, age-related muscle loss, which begins subtly in the forties and then accelerates (Delpino et al., 2022).
The European Union also authorizes a specific health claim on this point: at 3 g per day, creatine enhances the effect of resistance training on muscle strength after the age of 55 (EU Regulation 2017/672). Resistance training simply means muscle strengthening: weights, resistance bands, core exercises, and uphill climbs. Creatine alone does not make muscles grow; it is the combination of creatine and strength training that works.
Useful only for strength training, or also for endurance sports?
Although it was popularized by bodybuilding, creatine is now a versatile tool for optimizing performance. In running, trail running, cycling, or triathlon, it helps you better handle training load, preserve muscle over the long term, and make the difference at key moments in your events.
It complements the fundamentals; it does not replace them: sleep, your diet, and well-structured recovery, with proteins suited to endurance sports, remain the foundation. My conviction since 2008: eating real, simple food all year round is what keeps you going.
Want to know what role creatine and the rest of your nutrition can play in your routine? The diagnostic app will answer you in three minutes.
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FAQ: your questions about creatine for endurance sports
Is creatine useful for running and trail running?
Yes, but not as a primary fuel source: the aerobic system uses carbohydrates and fats, not phosphocreatine.
Creatine helps with short, intense efforts inserted into a long effort (surges, climbs, intervals, final sprint), with recovery, and with maintaining muscle mass during a demanding season. Take 3 to 5g per day, every day.
What daily dose of creatine should an endurance athlete take?
3 to 5g of creatine monohydrate per day, every day, including rest days.
This is the dose validated by research and adopted by European regulations, which authorize an efficacy claim from 3g per day. Muscle stores are saturated after 3 to 4 weeks of daily use, without a loading phase.
Does creatine make you gain weight?
Creatine does not cause fat gain. It can lead to a weight gain of 0.5 to 1.5 kg at the beginning of supplementation, due to water retention inside muscle cells.
For an endurance athlete, this improved cellular hydration is more of an advantage, particularly during events in hot weather.
When should you take creatine: before or after training?
The precise timing matters little: creatine works through accumulation, not like a stimulant.
The most practical approach is to take it after training, with carbohydrates and protein, which facilitate its transport to the muscles. On rest days, take it at breakfast. Daily consistency is what produces results.
Is creatine dangerous for the kidneys?
In healthy people, studies conducted over up to five years of continuous use show no impairment of kidney function.
Creatine slightly increases blood creatinine, a simple marker of its breakdown, without any link to kidney disease. If you have existing kidney disease, ask your doctor for advice before supplementing.
Should you do a creatine loading phase?
No. The loading phase (20 g per day for 5 to 7 days) saturates the muscles faster but often causes digestive discomfort.
With a simple dose of 3 to 5 g per day, you reach exactly the same muscle saturation in 3 to 4 weeks, gradually and without side effects.
Sources and studies:
-
Kreider et al., 2017 — ISSN Position Stand: safety and efficacy of creatine supplementation — https://pubmed.ncbi.nlm.nih.gov/28615996/ (full text on PMC: https://pmc.ncbi.nlm.nih.gov/articles/PMC5469049/)
→ The world's leading reference (efficacy + safety)
Specifically on endurance
-
Fernandez-Landa et al., 2023, Sports Medicine — Effects of Creatine Monohydrate on Endurance Performance in a Trained Population: A Systematic Review and Meta-analysis — https://pubmed.ncbi.nlm.nih.gov/36877404/
-
Forbes et al., 2023, JISSN — Creatine supplementation and endurance performance: surges and sprints to win the race — https://www.tandfonline.com/doi/full/10.1080/15502783.2023.2204071
- Gras et al., 2021 — Creatine supplementation and VO2max: a systematic review and meta-analysis — https://pubmed.ncbi.nlm.nih.gov/34859731/
On thermoregulation / hydration (for your "water vs. muscle" section)
- Lopez et al., 2009, Journal of Athletic Training — Does Creatine Supplementation Hinder Exercise Heat Tolerance or Hydration Status? — https://pmc.ncbi.nlm.nih.gov/articles/PMC2657025/
For specific populations
- Delpino et al., 2022 — Influence of age, sex, and type of exercise on the efficacy of creatine supplementation on lean body mass — https://pubmed.ncbi.nlm.nih.gov/35986981/
- Poortmans & Francaux, 2000 — Adverse effects of creatine supplementation: fact or fiction? — https://pubmed.ncbi.nlm.nih.gov/10999421/
