What are the effects of creatine (creatine monohydrate) as a dietary supplement?

From the Guidelines

Creatine monohydrate is a safe and effective supplement for enhancing exercise performance and increasing muscle mass, and I recommend taking 3-5 grams daily, as supported by the most recent and highest quality study 1. The recommended dosage can be consumed at any time of day with water or mixed into a beverage.

• No loading phase is necessary, though some people opt for a loading protocol of 20 grams daily (split into 4 doses) for 5-7 days before dropping to the maintenance dose.
• Creatine works by increasing your body's phosphocreatine stores, which helps regenerate ATP (your cells' energy currency) during high-intensity exercise, allowing you to perform more reps or maintain higher intensity during workouts.
• This leads to greater training volume and, consequently, better strength and muscle gains over time.
• Creatine also draws water into muscle cells, potentially increasing cell volume and signaling for muscle growth.
• Most people experience a 2-4 pound weight gain from water retention when starting creatine.
• The supplement is particularly effective for high-intensity, short-duration activities like weightlifting and sprinting, though endurance athletes may see modest benefits as well.
• It is essential to note that creatine has been extensively studied and shows no harmful effects on kidney or liver function in healthy individuals when taken at recommended doses, as confirmed by 1, which investigated the use of dietary supplements in living kidney donors and found no direct nephrotoxicity associated with creatine monohydrate.
• However, it is crucial to consider the potential impact of creatine supplementation on creatinine clearance measurements, as highlighted in 1, which may lead to misclassification of acute kidney injury in individuals with pre-existing kidney issues.

From the Research

Benefits of Creatine Supplementation

• Creatine supplementation increases muscle performance in short-duration, high-intensity resistance exercises 2, 3
• It may enhance postexercise recovery, injury prevention, rehabilitation, and provide neurologic benefits 4
• Creatine supplementation is beneficial for older adults and patient populations, promoting general health and aiding in recovery from injury and/or management of chronic disease 5, 6

Safety and Adverse Effects

• Creatine is a relatively safe supplement with few adverse effects reported, the most common being transient water retention in the early stages of supplementation 3, 5
• High doses or prolonged use may lead to liver and renal complications, but evidence is limited 3
• There is no conclusive evidence that creatine causes kidney damage, renal dysfunction, hair loss, dehydration, or muscle cramping 5

Dosage and Forms

• Effective dosing for creatine supplementation includes loading with 0.3 g·kg·d for 5 to 7 days, followed by maintenance dosing at 0.03 g·kg·d 3
• Creatine monohydrate is the most studied form, with other forms such as creatine ethyl ester showing no added benefits 3
• A creatine 'loading-phase' is not necessary to increase intramuscular stores of creatine 3, 5

Common Misconceptions

• Creatine is not an anabolic steroid 5
• It does not increase fat mass or lead to dehydration and muscle cramping 5
• Creatine supplementation is beneficial for both males and females, and is not limited to resistance or power type activities 5