What is Creatine?
Creatine is a nitrogenous organic acid that occurs naturally in vertebrates. Its main role is to facilitate recycling of adenosine triphosphate (ATP), the energy currency of the cell, by donating a phosphate group to ADP, producing ATP. This process occurs in mitochondria during periods of high energy demand such as during muscle contraction.
In skeletal muscles, approximately 95% of the creatine pool is in the form of phosphocreatine (PCr). PCr donates its phosphate group to ADP to form ATP and then quickly reforms back into PCr through a reaction catalyzed by creatine kinase (CK).The rest of the creatine pool is in the free creatine (Cr) form. Creatine uptake into muscle cells is mediated by the SLC6A8 transporter.
In healthy individuals, muscles contain approximately 0.3 mmol/kg of creatine, which can be increased to 16-20 mmol/kg following dietary supplementation.
Creatine has a number of anabolic effects on muscle tissue, including:
– Increased protein synthesis
– Stimulation of growth hormone release
– Improved recovery from exercise
– Increased muscle mass and strength
Possible side effects of creatine supplementation include:
– Gastrointestinal distress (cramping, diarrhea, etc.)
– Muscle cramps
– Weight gain
– Kidney damage (with long-term use at high doses)
– Testosterone suppression (with long-term use at high doses)[7]
The most common form of creatine supplement is creatine monohydrate, which is highly bioavailable and easy to take. Creatine supplementation is generally safe, but it is important to consult with a healthcare professional before starting any supplement regimen.
Long-term effects of creatine supplementation have not been well studied, so it is important to consult with a healthcare professional before starting any supplement regimen.
Pharmacokinetics
Creatine is rapidly taken up by muscle cells, with 98% of creatine present in muscle cells within 24 hours of oral supplementation. Muscle creatine levels peak at approximately 2-3 hours after loading and then decline over the next 3-5 hours, reaching baseline levels after 5-7 hours. Muscle creatine levels remain elevated for 24-48 hours following loading,but return to baseline levels within 2 weeks.
At rest, approximately 60% of the creatine pool is in the form of PCr, while the other 40% is in the free Cr form. During exercise, PCr is used to regenerate ATP, and Cr is used to replenish the PCr pool.
After supplementation, muscle creatine levels are elevated for 24-48 hours, but return to baseline levels within 2 weeks.
Dosage and Administration
The recommended dosage of creatine is 3-5 grams per day, taken with or without food. For best results, it is important to maintain a consistent daily intake. Creatine should be cycled (taken for 5-7 days followed by 2-4 weeks off) to avoid tolerance and minimize side effects.
If you are new to supplementation, it is recommended to start with the lowest possible dose and increase as tolerated. Creatine should be taken for at least 8 weeks to see results.
Is Creatine bad for you?
No, creatine is not bad for you. Creatine is a naturally occurring compound that is safe to take in supplement form. However, as with any supplement, there are potential side effects that can occur. These side effects are typically mild and resolve on their own with continued use. The most common side effects of creatine supplementation include gastrointestinal distress, muscle cramps, and weight gain. If you experience any severe or persistent side effects, it is important to consult with a healthcare professional. Long-term studies on the safety of creatine supplementation have not been conducted, so it is important to consult with a healthcare professional before starting any supplement regimen.
Research
Creatine has been extensively studied and shown to be safe and effective in a variety of populations.
Athletes
Creatine supplementation has been shown to improve exercise performance and increase muscle mass in athletes.
In one study, rugby players who supplemented with creatine for 8 weeks increased their bench press 1RM by an average of 5kg and their squat 1RM by an average of 10kg.Another study showed that creatine supplementation improved sprint performance by 3.3% in sprinters and 2.9% in middle-distance runners.
Elderly
Creatine supplementation has also been shown to improve exercise performance in the elderly. In one study, elderly women who supplemented with creatine for 8 weeks increased their leg press 1RM by an average of 14kg and their bench press 1RM by an average of 5kg.Another study showed that elderly men who supplemented with creatine for 12 weeks increased their leg press 1RM by an average of 17kg and their bench press 1RM by an average of 9kg.
Creatine supplementation has also been shown to improve cognitive function in the elderly. In one study, elderly women who supplemented with creatine for 8 weeks improved their performance on a variety of cognitive tests.[11] Another study showed that elderly men who supplemented with creatine for 12 weeks improved their performance on a variety of cognitive tests, including measures of executive function, working memory, and verbal fluency.
Healthy Adults
Creatine supplementation has also been shown to improve exercise performance in healthy adults. In one study, healthy adults who supplemented with creatine for 5 days increased their bench press 1RM by an average of 4kg and their squat 1RM by an average of 7kg. Another study showed that healthy adults who supplemented with creatine for 6 weeks increased their leg press 1RM by an average of 9kg.
In addition to its effects on exercise performance, creatine supplementation has also been shown to increase muscle mass in healthy adults. In one study, healthy men who supplemented with creatine for 8 weeks increased their lean body mass by an average of 2.2kg. Another study showed that healthy men who supplemented with creatine for 12 weeks increased their lean body mass by an average of 3.4kg.
Creatine supplementation has also been shown to improve cognitive function in healthy adults. In one study, healthy young adults who supplemented with creatine for 5 days improved their performance on a variety of cognitive tests.[16] Another study showed that healthy young adults who supplemented with creatine for 6 weeks improved their performance on a variety of cognitive tests, including measures of executive function and working memory.
