Creatine is the most studied sports supplement with the highest level of scientific evidence in the world. That is an unquestionable fact. However, heavy marketing from the supplement industry has pushed creatine as a magic pill for all sports — including distance running.
If you run 5Ks, 10Ks, half-marathons, or marathons, you have probably wondered if you should add creatine to your post-workout shake.
The answer, rooted in exercise physiology, is counterintuitive: for the long-distance runner, creatine rarely provides relevant benefits and may even hurt your pace. Here is why.
The Physiology Unmasked: The 1-Minute Rule
To understand why creatine falls short in endurance sports, we need to look at how your body produces energy.
Creatine works exclusively within the ATP-CP (phosphagen) system. This is our fastest and most explosive energy pathway, used for maximal and extremely short efforts, such as an Olympic weightlifting movement, a jump, or a 100-meter sprint.
The major detail that supplement marketing omits is the duration of this pathway. Phosphocreatine stores in the muscle deplete after about 10 to 15 seconds of maximal effort. After approximately 1 minute of exercise, this energy system’s contribution drops drastically to near zero.
From that point on, your body relies on aerobic metabolism (the oxidation of carbohydrates and fats). Since a 5K race or a marathon lasts from tens of minutes to several hours, the extra reserve of intramuscular creatine becomes physiologically irrelevant for maintaining your pace.
| Energy System | Primary Duration | Fuel Used | Creatine Impact |
| Phosphagen (ATP-CP) | 0 to 15 seconds | Phosphocreatine (Muscle Store) | High (Short Sprints) |
| Glycolytic (Anaerobic) | 15 sec to 2 minutes | Glycogen (Carbohydrate) | None |
| Oxidative (Aerobic) | From 2 minutes onwards | Glycogen & Fat | None |
The Cost of Extra Weight on Running Economy
In distance running, “running economy” is one of the pillars of performance. It refers to the amount of energy and oxygen you expend to move your body mass at a given speed. The heavier you are, the higher the energy cost per stride.
This is where creatine supplementation can become a problem.
Creatine monohydrate pulls water into the muscle cell (intracellular hydration). This process typically causes an acute weight gain ranging from 1 to 2 kg (2.2 to 4.4 lbs).
For an athlete in sports with short intermittent stimuli, this extra weight is not an issue. But for a marathoner taking around 40,000 steps during a race, carrying an extra 2 kg of pure intramuscular water exponentially increases the mechanical overload and energy expenditure, negating any potential marginal benefit in a final sprint.
When Does Creatine Make Sense in Running?
Sports nutrition does not deal in absolutes. There are very specific scenarios where creatine successfully crosses paths with running:
- Track Sprinters: 100m, 200m, or even 400m athletes, where the ATP-CP pathway is the primary driver.
- Concurrent Training Focused on Hypertrophy: If you are a recreational runner whose main current goal is significant muscle mass gain at the gym, and running serves merely as a cardiovascular complement.
- Masters Athletes (Sarcopenia Prevention): For older runners, creatine can hold clinical value in maintaining lean mass and strength, although the benefit targets muscle health rather than directly lowering your finishing time on the clock.
The Practical Verdict
If your goal is to lower your time in the 5K, 10K, or marathon, your financial investment should not go toward creatine.
For endurance runners, the true ergogenic advantage comes from impeccable carbohydrate periodization, smart electrolyte replenishment, and, in some cases, caffeine or nitrate (beetroot juice) supplementation.
Save your money, prioritize what the scientific literature actually validates for your modality, and focus on the right fuel for your miles.
By Gabriel Bueno Bocchi, Registered Dietitian / Sports Nutritionist (University of Campinas – UNICAMP)