Creatine: What It Is, What It Does, and What the Research Shows
What Is Creatine?
Creatine is a naturally occurring compound found primarily in skeletal muscle. While often described as an amino acid, creatine itself isn't one of the standard 20 amino acids that build proteins. Instead, the body synthesizes creatine from three amino acids — arginine, glycine, and methionine — and also obtains it from foods like red meat and fish. Inside cells, creatine is stored as creatine phosphate (phosphocreatine), which plays a key role in rapid energy production during high-intensity activity.
Creatine monohydrate is the most studied and well-validated form of supplemental creatine; other forms do not consistently outperform it.
What Does Creatine Do?
Energy Production
Creatine's primary role in the body is to help regenerate adenosine triphosphate (ATP) — the cellular "energy currency" — during short bursts of intense activity. When muscles contract rapidly, ATP is used quickly, and phosphocreatine donates a phosphate group to help resynthesize ATP so energy production can continue.
Muscle Strength and Performance
A large body of research, including meta-analyses and double-blind, placebo-controlled trials, shows that creatine supplementation enhances strength and high-intensity performance when combined with resistance training. One systematic review and meta-analysis found that adults supplementing with creatine achieved significantly greater increases in both upper-body and lower-body strength than those taking a placebo.
Extended Training Capacity and Recovery
Creatine may also help athletes tolerate heavier training volumes and recover more effectively. A position stand by the International Society of Sports Nutrition (ISSN) concluded that creatine supplementation can enhance glycogen storage, reduce exercise-induced inflammation, and support recovery when training intensity is high.
Emerging Cognitive Benefits
Beyond physical performance, research suggests creatine may support brain function. In a double-blind, placebo-controlled study of young adult vegetarians, 5 g/day of creatine for six weeks significantly improved working memory and reasoning performance compared with placebo.
Which Activities Benefit Most from Creatine? What Does the Research Say?
Creatine is most effective for high-intensity, short-duration activities where rapid ATP turnover limits performance. These include:
- Weightlifting and strength training
- Sprinting and explosive movements
- High-intensity interval training (HIIT)
Research shows that creatine supplementation boosts muscle strength, power output, and performance during repeated bouts of intense activity. It is less effective for prolonged endurance exercise (e.g., marathon running) because these activities rely more on aerobic metabolism than the phosphocreatine system.
Examples from the literature:
- Meta-analytic evidence shows significantly greater strength gains with creatine + resistance training versus placebo + training.
- Creatine enhances sprinter performance and repeated sprints in several controlled studies.
Some research suggests benefits may vary by activity type and individual factors (e.g., muscle creatine stores and training history), and benefits are most reliably seen in short, high-power efforts.
How to Supplement With Creatine
Typical Dosing Protocol
There are two common strategies for creatine supplementation:
-
Standard Daily Dose (Maintenance):
– 3 to 5 g/day of creatine monohydrate
– Effective without the need for a loading phase -
Loading-Plus-Maintenance:
– 20–25 g/day (split into 4–5 g doses) for 5–7 days to saturate muscle creatine stores
– Follow with 3–5 g/day maintenance
– Another valid approach, although many experts find it unnecessary for long-term benefits
No evidence shows that doses above 5 g/day provide additional performance benefit for most people, and higher doses may simply increase side effects without extra gains.
Timing
While daily consistency matters most, consuming creatine near training sessions (before or after workouts) is a popular approach that may optimize uptake when paired with carbohydrate and protein, though evidence on timing effects is mixed.
Are There Side Effects With Creatine?
Creatine is one of the most extensively studied dietary supplements in sports nutrition, and long-term research generally supports its safety when taken at recommended dosages.
Common and mild effects may include:
- Water retention and slight weight gain — especially during loading phases due to increased muscle water content.
- Gastrointestinal discomfort in some individuals at higher doses.
Double-blind, placebo-controlled studies have found no detrimental changes in kidney or liver markers when creatine is taken at typical levels (3–5 g/day) in healthy adults. One trial evaluating renal biomarkers reported that short-term creatine use did not impair kidney function.
The ISSN position stand also notes that creatine does not increase dehydration, cramping, or electrolyte imbalance — contrary to some older myths — when used responsibly.
Rare Considerations
While creatine is generally safe for healthy adults, individuals with pre-existing kidney disease, liver conditions, or those on certain medications should consult a healthcare provider before use.
Summary
- Creatine is a naturally occurring compound stored in muscles and essential for rapid energy production.
- It enhances high-intensity performance and strength gains when combined with resistance training.
- Creatine shows promise beyond athletics, including cognitive support in controlled trials.
- Standard supplementation is 3–5 g/day, with or without a loading phase.
- Research supports its safety in healthy adults with minimal side effects at recommended doses.
Creatine remains one of the most evidence-backed sports nutrition supplements available, with decades of research supporting its use for strength, power, and cellular energy support.
Until next time, stay healthy!
Yours in health,
Dr. Gregg Gittins
