Creatine monohydrate is one of the most well-researched supplements, commonly used by avid gym-goers to wring more out of every workout.
Lately, however, creatine has gone mainstream, with claims it can help improve short-term memory and reasoning, reduce mental fatigue and even boost mood.
Creatine is both produced naturally in the liver, pancreas and kidneys, and is found in the food we eat, such as meat and oily fish. However, there’s evidence that many of us could stand to consume more. A 2025 analysis found that only a third of a nationally-representative sample of US adults consumed the recommended dietary creatine intake of 1g or more a day.
You may like
With a busy training schedule approaching at the end of 2025, I decided to see if daily supplementation could give my workouts and working day a much-needed pick-me-up.
To put it to the test, I started taking 4g of ESN Ultrapure Creatine Powder (fresh cherry flavor) mixed with 100ml of cold water first thing every morning.
I then consulted a medical expert in sports supplementation from ESN to understand how my anecdotal observations matched up with the scientific research.
Here’s what I found after 30 days of daily use.
1. At first, I felt dehydrated
The first thing I noticed—apart from the refreshingly tasty tart cherry flavor of this supplement—was that I felt dehydrated.
I’d read that this is a commonly reported side-effect and, while I may have been imagining it, the skin on my hands and face felt extra dry.
I also became rather, er, bunged up, though this abated after the first week or so. However, I didn’t experience any other symptoms of dehydration, like headaches.
You may like
Does creatine make you dehydrated?
I asked Mike O’Leary Ph.D, a specialist in medical research and sports supplements at ESN if my parched skin could be a side-effect of daily creatine use. In a word: no.
“This is actually one of the most common myths surrounding creatine, as research shows that creatine doesn’t cause dehydration,” he tells Fit&Well. “Creatine works by drawing water into your muscle cells, not pulling it away from other tissues.”
While studies examining heat tolerance, cramping and hydration markers found no increased dehydration risk with creatine use, O’Leary adds that because creatine increases intracellular water retention, some people initially feel they need more water.
“Think of your muscles as sponges that are now holding more fluid,” he explains. “Your body simply needs adequate intake to maintain balance throughout all tissues.”
Topping up daily water intake by 500ml to a liter while supplementing with creatine can help accommodate this fluid shift into the muscles, he says, helping maintain optimal hydration.
He also recommends monitoring urine color (pale yellow is ideal) and drinking consistently throughout the day, rather than chugging your daily quota of H2O at once.
2. My work capacity for exercise improved
This month-long test coincided with training for and completing my first solo HYROX race, followed immediately by a frankly ludicrous challenge that involved doing 300 kettlebell swings a day for 30 days.
While I am relatively active for a 38-year-old dad who’s had to give up his usual morning workout for the nursery run, this was a meaty step up in training volume and intensity compared with how I usually exercise.
Nevertheless, for the most part, my body was able to take this increased workload in its stride and I woke up feeling remarkably fresh despite the previous day’s exertions.
Creatine’s potential to boost workout output has been widely accepted since a landmark Swedish study back in 1992, which found daily supplementation boosted levels of phosphocreatine by approximately 20%.
This high-energy molecule rapidly regenerates adenosine triphosphate (ATP), the main energy currency of every cell in the human body.
More phosphocreatine means more energy for short-duration, high-intensity efforts, of the type I did to prepare for a HYROX race and swinging a heavy kettlebell between my legs.
Does creatine make exercise feel easier?
I asked O’Leary if my improved work capacity could be attributed to upping my creatine intake and he said it checked out.
“Think of it like extending your muscles’ battery life,” he says. “Your muscles store creatine phosphate, which rapidly regenerates ATP during intense efforts lasting 1-10 seconds. Supplementing increases these stores by 20-40%, meaning you can sustain maximal effort slightly longer before fatigue sets in.”
For average exercisers, O’Leary says research suggests this translates to performing 1-2 more reps per set, a 5-15% improvement in high-intensity exercise capacity, recovering faster between sets and maintaining power output during repeated efforts.
The net result of this increased work capacity is long-term physical adaptations, like improved strength and stamina. And it’s just as effective for beginners and older adults alike.
“Beginners benefit because creatine helps them handle training volume better, potentially accelerating initial strength gains and adaptation,” says O’Leary. “For older adults (50-plus), creatine is particularly valuable as it combats age-related muscle loss (sarcopenia), supports cognitive function and may help maintain bone density.”
Beyond the gym, O’Leary says many users report better performance in recreational sports, yard work or simply playing with their kids.
I woke up feeling more mentally switched on, as well as physically fresher.
This was something I didn’t expect to notice. My increased training load meant I often had to exercise after work or after dinner, pushing my bedtime back, and back, and back.
And yet, despite not getting anywhere near enough sleep, I rarely felt mentally fatigued.
I was able to juggle an unholy number of tasks, including executing the mental gymnastics required to file my tax return on time.
I shouldn’t have been quite so surprised. A human trial in 2003 was the first to show that oral creatine supplementation can improve cognitive performance, not just muscle function.
Can creatine boost brainpower?
Certainly. O’Leary says creatine acts in the brain much like it does in the muscles. “Your brain, like muscles, uses ATP for function,” he explains.
Research shows promising improvements in working memory, processing speed and mental fatigue resistance, especially during stressful conditions like sleep deprivation, mental exhaustion or demanding cognitive tasks.
“Think of it as helping your brain’s power grid stay stable when demand is high,” he elaborates. Studies suggest the benefits are most pronounced with vegetarians, whose baseline creatine levels are lower, and older adults.
“Effects appear modest but meaningful, typically around 5-10% improvements in cognitive testing under challenging conditions,” he says, adding that while the evidence is encouraging and growing, we need more large-scale studies to fully establish these effects.
That said, O’Leary stresses that creatine supplementation should not replace getting enough good-quality sleep.
“It’s quite plausible that creatine contributed to your resilience,” he says. “Sleep deprivation depletes brain energy reserves and intense training adds physical stress. Creatine helps buffer against both.”
My scenario of combined physical and mental stress is exactly where creatine’s neuroprotective effects may become noticeable.
However, he says, this research area is still emerging and individual responses vary.
“While creatine played a supportive role in maintaining your mental clarity, it’s not a magic solution or sleep replacement. Proper rest remains essential for optimal recovery. Consider creatine as one helpful factor among several, rather than the sole explanation for your experience.”
Browse creatine supplements on Amazon
About our expertAbout our expertMike O’Leary
Social Links Navigation
Mike O’Leary Ph.D is a specialist in medical research and sports supplements product development and head of product at German sports nutrition company ESN. He completed his PhD in Natural Medicine at the International Quantum University for Integrative Medicine. Before that O’Leary completed a Bachelor of Science in Exercise Science at Minnesota State Moorhead.
