Yes, athletes can take creatine. It is not banned by the World Anti-Doping Agency (WADA), the NCAA, the International Olympic Committee, or any major professional sports league. Creatine monohydrate is one of the most widely studied and widely used sports supplements in the world, with decades of research supporting both its effectiveness and its safety in healthy people.
Why Creatine Is Legal in All Sports
Creatine is a naturally occurring compound found in meat, fish, and your own body. Your liver and kidneys produce about 1 to 2 grams of it daily. Because it’s a normal part of human biology and present in everyday food, no major sports governing body classifies it as a performance-enhancing drug. It has never appeared on WADA’s Prohibited List, and the NCAA permits athletes to use it, though NCAA programs cannot directly provide it to their athletes (they can provide information about it). Professional leagues including the NFL, NBA, and MLB also allow it.
How Creatine Works in Your Muscles
Your muscles run on a molecule called ATP, which gets used up within seconds of intense effort. Creatine’s job is to recycle that ATP as fast as possible. When you supplement with creatine, you increase your muscles’ stores of phosphocreatine, which acts as a rapid energy buffer. During a heavy lift or a sprint, the enzyme creatine kinase strips the phosphate group off phosphocreatine and hands it to spent ATP molecules, regenerating them so your muscles can keep contracting.
This shuttle system also moves energy from the mitochondria (where your cells produce energy) out to the parts of the muscle fiber that need it most: the contractile proteins that generate force, the calcium pumps that control muscle relaxation, and the sodium-potassium pumps that maintain electrical signaling. More stored phosphocreatine means more fuel available for those first 10 to 15 seconds of maximal effort, and faster recovery between repeated bouts.
Strength, Power, and Muscle Growth
The performance benefits are most pronounced in activities that rely on short, intense bursts: sprinting, jumping, weightlifting, and similar efforts. When creatine is combined with resistance training, the gains in muscle size consistently outpace what training alone produces. A systematic review with meta-analysis found that people taking creatine while resistance training saw upper arm muscle thickness increase 16 to 20%, compared to 2 to 6% in placebo groups doing the same training. For the muscles around the knee, creatine groups gained roughly 10 to 12% in thickness versus 3 to 6% without it.
These aren’t small differences. Across multiple muscle groups and multiple studies, creatine roughly doubled the rate of muscle growth when paired with the same training program. The effect is driven partly by the ability to train harder (more reps, more total work) and partly by creatine’s direct effects on muscle cell hydration and protein synthesis signaling.
Endurance Sports: A Different Picture
If you’re a distance runner or cyclist, the picture is more nuanced. Creatine improves time to exhaustion during high-intensity endurance efforts, likely because it expands your anaerobic work capacity. But research has not consistently shown improvements in steady-state time trial performance.
Where creatine does seem to help endurance athletes is during surges: the repeated accelerations in a road cycling race, the kick at the end of a 5K, or the hill repeats in a cross-country course. If your sport involves changes of pace or a finishing sprint, creatine may give you an edge in those race-defining moments even if it doesn’t improve your cruising speed.
Recovery After Hard Training
A meta-analysis published in Sports Medicine found that creatine users showed significantly lower markers of muscle damage 48 to 90 hours after a single bout of strenuous exercise. Inflammation markers were also lower at 24 to 36 hours and 48 to 90 hours post-exercise, with large effect sizes. Muscle soreness scores were moderately reduced at 24 hours.
There’s a catch, though. This benefit applied to recovery from a single hard session. When researchers looked at chronic training over weeks, the pattern reversed: muscle damage markers were actually higher in the creatine group at 24 hours post-exercise. One explanation is that creatine allows you to train harder over time, which creates more mechanical stress on muscle fibers. So creatine may speed recovery from any given session while also enabling workouts that are more demanding to recover from.
Brain Health and Concussion Protection
Your brain is one of the most energy-hungry organs in your body, and it relies on the same phosphocreatine system your muscles do. In nonclinical populations, creatine supplementation has been shown to improve working memory and processing speed. The cognitive benefits appear greatest when the brain is under energy stress, such as during sleep deprivation or oxygen restriction.
For contact sport athletes, the neuroprotective angle is especially interesting. In animal models, creatine supplementation before experimental brain injury reduced cortical damage by 36 to 50%, primarily by protecting mitochondrial function and maintaining ATP levels. In human traumatic brain injury cases, creatine administration reduced post-traumatic amnesia and improved recovery of cognitive function, headaches, dizziness, and fatigue. Research specifically on mild concussions in athletes is still limited, but the cellular rationale for pre-loading creatine before a sport with head-impact risk is strong.
Dosing Protocol
The standard approach involves two phases. A loading phase of 20 to 25 grams per day (split into 4 or 5 doses) for 5 to 7 days saturates your muscles quickly. This is followed by a maintenance phase of 5 to 7 grams per day to keep levels topped off. For someone who wants to skip the loading phase, taking 5 grams daily will reach the same saturation point, but it takes about 3 to 4 weeks to get there.
Creatine monohydrate is the form used in the vast majority of research. It is also the cheapest. Other formulations (creatine hydrochloride, buffered creatine, creatine ethyl ester) have not demonstrated any advantage over monohydrate in head-to-head comparisons.
Weight Gain and Water Retention
You will likely gain weight during the first week. This is water, not fat. Creatine pulls water into muscle cells, and a study tracking total body water found that the largest increase (about 1.4 liters) occurred during the first week of supplementation. After 28 days, total body water was up by roughly 2 liters compared to baseline. This intracellular water retention is actually part of how creatine works: it creates a more hydrated environment inside muscle fibers that supports protein synthesis.
For athletes in weight-class sports like wrestling, boxing, or lightweight rowing, this water weight is worth planning around. It won’t affect your body composition in terms of fat, but it will move the scale up by 1 to 2 kilograms.
Kidney Safety
The most persistent concern about creatine is kidney damage, and the evidence consistently shows it’s unfounded in healthy people. A systematic review and meta-analysis found that creatine supplementation causes a modest, statistically significant rise in serum creatinine (a waste product of creatine metabolism that doctors use to estimate kidney function). But when researchers measured actual kidney filtration rates directly, there was no change. The creatinine bump is a predictable chemical byproduct of having more creatine in your system, not a sign of kidney stress.
If you’re supplementing with creatine and get routine bloodwork, let your doctor know. Otherwise, a slightly elevated creatinine reading could trigger unnecessary concern or follow-up testing. People with pre-existing kidney disease should discuss supplementation with their physician, but for athletes with healthy kidneys, the evidence across multiple studies is reassuring.
Younger Athletes
Many creatine products carry labels warning against use by anyone under 18. These warnings are not based on evidence of harm. They exist as a legal precaution because very few studies have directly examined creatine safety in adolescents. A review published in Frontiers in Nutrition found that no studies to date had been specifically designed to assess creatine safety in youth populations.
The International Society of Sports Nutrition has stated that younger athletes can consider creatine supplementation if they have parental approval, are already eating a well-rounded diet, use a quality product, and follow standard dosing guidelines. The biological mechanism is the same in a 16-year-old as in a 25-year-old. The caution around younger athletes is about the absence of dedicated research, not the presence of known risks.