Creatine is not a new supplement. It's been used in sports science since the 1970s and has over 1,000 published human studies. It's not a grey area.
Here's what it does, how well it works, and whether it's worth taking.
What Creatine Is
Creatine is a naturally occurring compound synthesised in the liver and kidneys from amino acids (primarily arginine and glycine). It's also found in food, primarily red meat and fish - about 1-2g per 500g of beef.
The body stores creatine primarily in skeletal muscle (95%), where it's used to regenerate ATP (adenosine triphosphate) - the immediate energy currency cells use for short, high-intensity effort.
When muscles need to contract explosively or repeatedly, ATP breaks down to ADP. Phosphocreatine (creatine bound to a phosphate group, stored in muscle) donates a phosphate to ADP, regenerating ATP quickly. This system powers the first 6-12 seconds of maximum-intensity effort: a sprint, a heavy squat, an explosive jump.
Creatine supplementation increases the amount of phosphocreatine stored in muscle - which means more rapid ATP regeneration, more power output per rep, and better recovery between high-intensity efforts.
What the Evidence Shows
Strength and Power Output
The evidence here is about as solid as nutrition research gets. A 2003 meta-analysis in the Journal of Strength and Conditioning Research - covering 22 RCTs - found that creatine supplementation combined with resistance training produced an average 8% increase in maximum strength and 14% increase in explosive power output compared to placebo groups.
A more recent 2017 meta-analysis in the Journal of the International Society of Sports Nutrition confirmed these effects across diverse populations and training conditions. The upper body and lower body strength gains were consistent across studies.
The effect is dose-dependent and most pronounced in:
- Exercises lasting 5-150 seconds (the phosphocreatine energy system's primary contribution)
- High-intensity interval efforts
- Heavy compound resistance training (squat, deadlift, bench press)
It has minimal effect on pure endurance performance (marathon running, long-distance cycling) - the phosphocreatine system barely contributes at sustained low-intensity effort.
Muscle Gain
Creatine supports muscle gain through multiple mechanisms beyond just enabling more reps. It draws water into muscle cells (cell volumisation), which is a mechanistic trigger for anabolic signalling. It also supports satellite cell activation and myogenic gene expression.
A 2012 meta-analysis in Sports Medicine found significantly greater lean mass gains in creatine vs. placebo groups across 22 training studies. Average additional lean mass gain: about 1-2kg over 4-12 weeks compared to training without creatine.
This is not water weight. Initial creatine loading causes some water retention in muscle (1-3kg), which is the "bloating" concern some people have. But studies specifically measuring fat-free mass by DEXA confirm genuine muscle fibre growth beyond the water component.
Cognitive Function
Emerging evidence, less established than the performance research but consistent. Creatine is present in brain tissue and the same PCr/ATP energy system operates in neurons.
A 2022 meta-analysis in Nutritional Reviews found creatine supplementation improved cognitive performance under conditions of mental fatigue and sleep deprivation. A 2021 trial found significant improvements in working memory and executive function in adults taking creatine compared to placebo.
Vegetarians and vegans - who consume essentially no dietary creatine - show larger cognitive response to supplementation, suggesting baseline creatine stores influence the effect.
Older Adults
Creatine is particularly well-researched for preserving muscle mass in older adults, where sarcopenia (age-related muscle loss) is a significant health issue. A 2017 systematic review in Experimental Gerontology found that creatine supplementation combined with resistance training significantly increased lean mass and functional strength in adults over 55 compared to training alone.
This is arguably the most underappreciated application of creatine - it's often marketed primarily to young athletes, but the evidence for older adults is just as strong.
Forms of Creatine: Which One to Buy
There are multiple forms of creatine supplements. Here's where the evidence lands:
| Form | Evidence | Notes |
|---|---|---|
| Creatine monohydrate | Very strong | Cheapest, best researched, standard reference form |
| Creatine HCl | Limited | Claimed better solubility, similar effect but less studied |
| Buffered creatine (Kre-Alkalyn) | Weak | No significant advantage over monohydrate in head-to-head |
| Creatine ethyl ester | Weak | Inferior to monohydrate in RCTs |
| Micronised monohydrate | Same as standard | Smaller particle size, mixes better, same effect |
The conclusion from the research: creatine monohydrate remains the most effective and best-evidenced form. It's also the cheapest. Expensive "advanced" creatine forms offer no proven advantage.
Dosing: Loading vs Maintenance
Loading protocol: 20g per day (divided into 4 x 5g doses) for 5-7 days, then 3-5g/day maintenance. This saturates muscle creatine stores rapidly - performance benefits within the first week.
No-load protocol: 3-5g per day from the start. Muscle creatine stores reach saturation in approximately 4 weeks. Same endpoint as loading, just slower to get there. This avoids the initial gastrointestinal discomfort some people experience from 20g/day loading doses.
Timing: Research shows taking creatine post-workout is marginally better than pre-workout in some studies, though the difference is small. Consistency of daily intake matters more than precise timing.
With creatine and carbohydrates: Insulin improves creatine uptake into muscle. Taking creatine with a carbohydrate-containing meal or shake slightly increases uptake efficiency.
Safety: What the Research Shows Long-Term
This is where creatine's reputation has unfairly suffered from decades of gym myths. The evidence is clear.
Kidney damage: The most persistent myth. A 2021 review in Nutrients covering all available clinical evidence found no evidence of kidney damage from creatine supplementation in healthy adults across studies lasting up to 5 years. The concern originates from creatine raising serum creatinine (a waste product of creatine metabolism used to estimate kidney function) - it does raise creatinine, but this is not kidney damage; it's an expected metabolic consequence that doesn't indicate impaired function.
Hair loss: A 2009 study in South African rugby players found a significant increase in dihydrotestosterone (DHT) with creatine loading. DHT is associated with androgenetic alopecia (male pattern baldness). However, this study hasn't been replicated, and the testosterone/DHT effects of creatine in other studies are negligible. The evidence for creatine causing hair loss is weak at this point - one small study that hasn't been confirmed.
Dehydration and cramping: Not supported by research. Multiple studies on athletes in hot conditions found no increased incidence of cramping or dehydration with creatine supplementation. Some research suggests creatine may actually support hydration by drawing water into muscle cells.
The International Society of Sports Nutrition has published consensus statements classifying creatine monohydrate as the most effective and safest ergogenic supplement for performance enhancement.
Who Doesn't Benefit (and Why)
About 25-30% of people are "creatine non-responders" - their muscle creatine stores don't increase significantly with supplementation. This appears to be related to baseline muscle creatine levels: people who already have high levels (typically those with high meat intake or genetic predisposition to high creatine storage) see smaller responses. Those with naturally lower baseline creatine stores (including vegetarians and vegans) tend to be the strongest responders.
For protein intake and general macronutrient adequacy, creatine is a complementary tool - not a substitute for eating enough protein and training consistently.