Creatine is one of the most widely used and studied sports supplements, though it's also one of the most likely to raise concerns about potential kidney problems. This compound is actually a naturally occurring substance derived from the amino acids arginine , glycine, and methionine , which the body produces naturally in the liver, pancreas, and kidneys. It can also be obtained through a diet rich in red meat, fish, and poultry.
Its main function is to increase muscle strength and physical performance. It achieves this by maintaining stable levels of phosphocreatine , which is essential for rapidly regenerating ATP (adenosine triphosphate) , the immediate energy source for muscle contraction during explosive, high-intensity efforts.
Regarding kidney health, it has been mentioned that creatine increases protein assimilation, which could put excessive strain on the kidneys as they have to filter out protein waste. Following a very high-protein diet increases the risk of kidney failure, although it has not been scientifically proven that these conditions occur in healthy individuals. In fact, most research indicates that creatine does not cause kidney damage in individuals with normal kidney function, although it should be avoided by people with pre-existing kidney disease or liver conditions without medical supervision.
Muscle problems and hydration
Creatine , in addition to aiding protein assimilation, causes intracellular water retention . This phenomenon, known as cellular hydration, increases muscle fiber size and improves performance, but can lead to relative dehydration in other tissues, mineral deficiencies, and electrolyte imbalances in the body.
All of this can lead to muscle dysfunction during intense training sessions, especially in high temperatures . Contractions or cramps may occur more easily when taking creatine supplements, although some studies suggest this relationship is not clinically significant for most users.
Digestion and weight control
One of the potential negative effects of creatine is its ability to destabilize potassium and electrolyte levels . Some users may experience digestive issues such as indigestion, vomiting, gas, or bloating , especially if the supplement is taken in very high doses or not properly diluted in liquid.
Furthermore, creatine use often leads to a significant initial weight gain . It's crucial not to confuse this with an immediate increase in lean muscle mass; most of this increase is due to water retention within muscle cells. To avoid weight problems or discomfort, it's recommended to be cautious with the dosage and maintain consistent hydration.
Long-term side effects and contraindications
Despite the aforementioned contraindications, no current scientific studies show that creatine causes serious long-term side effects in healthy adults. Organizations such as the International Society of Sports Nutrition consider it a safe substance. Creatine monohydrate supplementation has even been documented as safe for up to 5 years in healthy individuals.
However, there are specific groups that should be cautious:
- Pregnant or breastfeeding womenThere is insufficient evidence of safety, so it is recommended to avoid it.
- Minimum age restrictionIts use in adolescents without professional supervision is not recommended, as information on its safety is limited.
- People with bipolar disorderIt could worsen symptoms of mania.
- DiabeticsCaution: Use if taking medications that alter blood sugar levels.
It's important to note that the product doesn't affect everyone in the same way. Moderate consumption helps prevent the development of kidney, digestive, or muscle complications.
Types of creatine, dosage and administration
The most studied and recommended variant, due to its efficacy and safety, is creatine monohydrate . There is also a micronized version , which simply has smaller particles to improve water solubility, although its effect is the same. Other versions, such as creatine HCl or Kre-Alkalyn, have not demonstrated significant advantages over monohydrate.
Regarding administration, there are two main strategies:
- Loading phaseIt consists of taking approximately 20 daily grams (divided into 4 doses) for 5 to 7 days to saturate muscle stores quickly.
- Maintenance phaseA constant dose of 3 to 5 grams dailyThis is the most gradual and recommended option to avoid gastrointestinal discomfort.
Regarding timing, it can be taken at any time, although it is suggested that consuming it after exercise along with carbohydrates and proteins may promote its absorption.
Common myths about creatine
It's common to find misinformation about this supplement. It's vital to clarify that creatine is not a steroid ; it doesn't alter hormones or testosterone levels. There is also no solid clinical evidence linking its use to hair loss or baldness, as this process depends primarily on genetics and hormones.
Another point of confusion is the difference between creatine and creatinine . Creatinine is a waste product that the body eliminates. Supplement use can raise creatinine levels in the blood, which might confuse a doctor during a kidney function test, but it doesn't mean the kidneys are damaged ; it simply means there's more of the substrate being processed.
This supplement is especially recommended for high-intensity , strength sports such as bodybuilding and weightlifting . Its effectiveness is lower in disciplines like long-distance running, swimming, and tennis, as these are not purely anaerobic, explosive activities. However, its use is also being explored in older adults to prevent sarcopenia and in people with cognitive stress to improve memory and concentration.
Creatine supplementation is an effective tool for improving strength and recovery, provided it is evidence-based and tailored to individual health. As long as appropriate dosages and optimal hydration are maintained, it represents a safe option for healthy adults seeking to optimize their physical performance and preserve muscle health.