Creatine 101: What It’s For, How to Use It, and Side Effects
Written by Joel Totoro, RD | 2025
Because athletes and bodybuilders are constantly looking for an edge to help their performance, it’s no surprise they often turn to one of the most-studied nutritional supplements for enhancing athletic performance: creatine.
But what is creatine, what are creatine side effects, and does creatine give you energy? If you want creatine explained, here’s your answer. Creatine, an amino acid stored mostly in skeletal muscle, is necessary for creating ATP – the body’s readily usable form of energy. Creatine is especially needed by your muscles during high-intensity exercise and training because it helps recharge the body’s energy level.
Half of the body’s creatine stores come from consuming creatine in food – mainly from meat, fish, and eggs – or from supplementation, while the other half comes from creatine’s synthesis in the liver and kidneys from amino acids.
How does creatine work?
Creatine supplementation promotes a well-hydrated environment, indicated by water mass gain, which in turn supports protein and carbohydrate metabolism both during and following exercise. Because creatine helps maintain hydration within the cells, an individual might actually weigh more when stepping on the scale after exercise because the supplemental creatine holds onto water in the muscles.
So, how fast does creatine work? Many people notice strength or endurance improvements within the first 1-2 weeks, although timing varies. Research shows that how long it takes creatine to start working depends on muscle saturation and consistent daily use.
What is creatine good for?
What does creatine do for athletes and weightlifters? The body’s physiological need for creatine increases with regular strenuous exercise and when muscle damage occurs. For an athlete, creatine helps the body more efficiently create energy to engage in activity.
So, what is creatine’s role in muscle development? Does creatine supplementation support muscle building? Yes, creatine supports the building of lean muscle. Much research over the past 10 years has examined the effects of creatine supplementation with resistance training. Research suggests numerous physiological changes occur with creatine supplementation, including supporting energy production, while helping to maintain and promote endurance, power output, and the growth of lean muscle. Supporting these systems can result in increased training capacity.
In addition to the athlete population, creatine has been shown to help maintain lean muscle mass in older individuals experiencing loss of muscle.
Cognitive support: What is creatine’s role in mental function?
Although creatine is best known for its role in athletic performance – to enhance an exercise program – research is emerging on its benefits for cognitive function. If you engage in intense mental work or experience sleep deprivation, creatine can provide support for cognitive function so you can perform at your best.
Is supplementing with creatine safe?
Research indicates that regular use of a creatine supplement is safe. One study concluded that supplementing with up to 30 grams of creatine daily for five years resulted in no notable long-term creatine side effects.
Still, some people ask, what are the side effects of creatine? Possible creatine side effects in men and women include bloating, temporary weight gain from water retention, or digestive upset if taken in large doses. To minimize side effects of creatine supplementation, stick to the recommended serving of 5 g, take creatine with food, and stay hydrated.
How to use creatine
Can I take creatine after a workout? Yes. Creatine post-workout benefits include muscle recovery and energy replenishment.
Although it is okay to vary the time you take creatine based on your schedule, it is recommended that you take it around your workout window. While creatine is usually best absorbed right before or after physical activity, making 30-90 minutes before or after exercise the ideal window – consistency in taking it is the crucial factor. So, choose to take creatine at whichever time will ensure you take it regularly.
To support absorption, Thorne uses a finely powdered, micronized creatine monohydrate – it’s colorless, odorless, and has enhanced solubility, making it easy to mix in water. Mix one level scoop with at least eight ounces of water, juice, or a preferred beverage daily, or as recommended by your health-care or performance professional.
Because an athlete needs to know that his or her nutritional supplements are trustworthy, every batch of a Thorne NSF Certified for Sport® supplement is tested for compliance with label claims and to ensure the absence of nearly 300 substances banned by major athletic organizations, such as stimulants, steroids, diuretics, beta-2 agonists, and masking agents. Look for the NSF Certified for Sport® logo on Thorne’s Creatine supplements.
Other frequently asked questions about creatine
Should I take creatine even if I don’t exercise?
For muscle support, creatine is most effective when paired with resistance training. If you’re not exercising, creatine’s benefits for strength and muscle growth are not as great. However, there is evidence for cognitive and cellular health benefits.
Will creatine make me bulky?
No, not by itself. Creatine supports muscle growth by improving performance and recovery, but you’ll only become “bulky” if you actively seek to build muscle with consistent resistance training and a surplus of calories.
Will creatine make me gain weight?
It might, but only temporarily from water retention. As stated earlier, creatine can cause a minor increase in weight – about five pounds in the first week or two – due to water retention in the muscles. Long-term weight gain would come from increased muscle mass due to increased exercise output and not from creatine in isolation.
Will creatine make me bloated or nauseous?
Some people report experiencing GI side effects from taking creatine in especially large doses. To minimize creatine monohydrate side effects, stick to the recommended serving of 5 g at a time, take creatine with food, and drink plenty of water to stay hydrated.
Should I only take creatine when I exercise?
No. Creatine’s benefits are best if allowed to saturate your muscles over time. You’ll often hear about the “creatine loading phase,” where active individuals take creatine even on rest days. For the best creatine results, you should supplement with creatine daily to maintain saturation.
Is creatine a stimulant? Does creatine make you jittery?
No. Creatine is not a stimulant. Some pre-workout powders contain creatine along with other ingredients, like caffeine, that produce stimulating effects. Creatine on its own won’t make you feel jittery.
What are the different types of creatine?
Creatine monohydrate is the most researched and effective form of creatine. You may also see creatine monohydrate labeled as “micronized creatine,” which just means it has smaller particles for superior dissolvability and absorbability. Thorne’s Creatine supplements all use micronized creatine monohydrate. Creatine HCl is an alternative form of creatine, being marketed as causing less bloating. It is more expensive than creatine monohydrate, and further research is needed about creatine HCl’s effects in humans.
How much creatine should I take?
For maintenance, you should have one 5-g serving of Creatine daily. Consult with a health-care or performance professional for more personalized recommendations.
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Bemben M, Lamont H. Creatine supplementation and exercise performance. Sports Med2005;35(2):107-125.
Volek J, Rawson E. Scientific basis and practical aspects of creatine supplementation for athletes. Nutrition 2004;20(7-8):609-614.
Martone A, Lattanzio F, Abbatecola A, et al. Treating sarcopenia in older and oldest old. Curr Pharm Des 2015;21(13):1715-1722.
Kreider RB, Kalman DS, Antonio J, et al. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. J Int Soc Sports Nutr 2017;14:18.
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