Creatine Isn't Just For Muscle
- Sean Hashmi, MD
- 1 day ago
- 7 min read
A video with millions of views says creatine shrinks your fat cells by 30%. The evidence does not show that. The real story is more interesting, and it runs past muscle into your brain and into your kidney lab results in a way that trips people up. This article sorts the creatine claims that have data behind them, muscle, strength, and memory, from the ones invented for clicks, explains the kidney-lab twist only a nephrologist would flag, and gives you the exact dose that matters.
This is for anyone who takes creatine or is thinking about it, anyone who has seen the viral claims and wants the honest version, and anyone who has ever had a confusing creatinine result on a lab.
The Muscle Story: What Is Not In Dispute
Start with what is not a dispute. Creatine is a compound stored in your muscles and used to recharge their fast energy system, the phosphocreatine system, which powers short bursts of effort. Supplementing raises the amount you store.
In older adults, a 2017 meta-analysis by Chilibeck and colleagues found that creatine combined with resistance training added about 1.3 kilograms more lean tissue and produced greater strength gains than training alone.
Think of phosphocreatine as a rechargeable battery for your muscles. Creatine gives you a bigger battery, so the next hard rep or the next flight of stairs has more charge behind it.
Two Facts That Make It Click
First, about 95% of your creatine sits in skeletal muscle, and your body turns over roughly 1 to 2% of its stores every day. You are always topping off a slightly leaky tank.
Second, as you age you make less creatine, and you may be eating less meat. That is part of why the older-adult studies are the most convincing on the benefits.
The Brain: Why Creatine Is Suddenly Everywhere
The reason creatine is everywhere right now is not muscle. It is the brain.
Your brain runs on the same energy system as your body, but it is a hungry organ that burns about a fifth of your body's energy. A 2023 systematic review in Nutrition Reviews found that creatine modestly improves memory, with a pooled effect size of 0.3.
What That Number Actually Means
That 0.3 is a standardized mean difference, which measures how far ahead the creatine group was in standard deviations. By convention, 0.2 is small, 0.5 is medium, and 0.8 is large. So an effect size of 0.3 is real but modest. People on creatine did a little better on memory tests than placebo, measurable in the lab, but not night and day for any one person.
Why This Matters For Older Adults
Here is the detail that fits this channel. In adults aged 66 to 76, that effect size jumped to about 0.88, a large effect. In young adults, it was essentially zero.
A separate 2024 meta-analysis in Frontiers in Nutrition pointed the same way: better memory, better attention, and better processing speed, strongest when the brain was under demand. The signal is clearest in older adults, and several studies suggest a benefit when the brain is stressed, such as sleep deprivation or heavy cognitive load.
Same battery, different device. If you are under stress or short on sleep, the brain runs low, and topping off creatine seems to help it hold steady.
Be Careful About The Size Of This Claim
It is real, repeatable, and modest. This is not a dementia cure. Anyone telling you creatine reverses cognitive decline is ahead of the data. One more clue this molecule matters: rare genetic defects in how the body makes or transports creatine can cause a serious syndrome of developmental delay and seizures, which is why neurologists cared about creatine long before social media did.
The Kidney-Lab Twist Only A Nephrologist Flags
Now the part only a kidney doctor would talk about. If you start creatine, your kidney blood test can look worse, and it is not because the kidneys are worse.
Creatine gets converted in the body to creatinine, the same waste product used to track kidney function. Supplementing can nudge your serum creatinine up a little on a standard lab, on the order of a tenth of a point in individual studies.
A 2025 systematic review in BMC Nephrology pooled the trials and found that whatever small rise shows up in creatinine, the GFR, the real measure of how well your kidneys filter, does not change. That held up even in studies that measured GFR directly. The number on the page moves. The kidney is fine.
It is like stepping on a scale while holding a bag of groceries. The scale reads heavier, but you have not gained a pound of fat. You are holding something extra. Set the bag down, which is what a measured GFR does, and you are right where you started.
What To Do About It
Tell your doctor you take creatine. Mention it before anyone gets alarmed about the creatinine number that shows up on your labs.
Ask for a cystatin C if you need a precise number. Cystatin C is a kidney marker that is not affected by creatine, so it gives an accurate reading and sidesteps the supplement's effect on your blood test entirely.
The Viral Claims That Fail
Now a cleanup, because some viral creatine claims are out of hand.
Creatine shrinks fat cells by 30%. Not supported by human evidence.
Creatine boosts testosterone. The reliable trials do not show a meaningful change.
Mega-doses are dramatically better. Also not supported. Your muscles can only hold a finite amount, and 3 to 5 grams gets most people there.
A 2017 International Society of Sports Nutrition position stand concluded that creatine monohydrate is safe and effective at modest doses, and that loading phases are optional, not required.
What Is Real And Underrated
The underrated part is the functional benefit. In older adults, the added muscle and strength show up in ordinary movements: standing up from a chair more easily, the kind of thing that keeps people steady and independent.
The hype is selling you muscle you would get from training anyway, plus fat loss and a testosterone surge that are not there. Strip that away and you still have a cheap, well-studied supplement with real but specific benefits. That is the product.
The Bottom Line And The Dose
Buy plain creatine monohydrate. Skip the expensive blends that talk about absorption. It is the cheapest and most studied form.
Take 3 to 5 grams a day. No loading phase required.
Pair it with resistance training. That is where the muscle and strength benefit shows up, especially in older adults.
Ignore the fat-loss and testosterone claims. They are not supported by reliable trials.
Creatine is one of the rare supplements where the evidence is solid and the effect is small, and it lands exactly where this channel lives. Aging muscles and the aging brain are under strain, and that is where the best claims about creatine hold true.
Frequently Asked Questions
How much creatine should I take?
3 to 5 grams a day of plain creatine monohydrate. No loading phase is required. A 2017 International Society of Sports Nutrition position stand concluded that creatine monohydrate is safe and effective at modest doses and that loading is optional. Pair it with resistance training for the muscle and strength benefit.
Does creatine actually help memory?
Modestly, and mostly in older adults. A 2023 Nutrition Reviews systematic review found a pooled memory effect size of 0.3 (small but real). In adults aged 66 to 76, the effect size jumped to about 0.88 (large), while in young adults it was essentially zero. A 2024 Frontiers in Nutrition meta-analysis found benefits to memory, attention, and processing speed were strongest when the brain was under demand, such as sleep deprivation or heavy cognitive load. It is not a dementia cure.
Why does creatine make my kidney labs look worse?
Creatine converts in the body to creatinine, the same waste product used to estimate kidney function. Supplementing can nudge serum creatinine up slightly on a standard lab, on the order of a tenth of a point. A 2025 BMC Nephrology systematic review found that measured GFR, the real filtration measure, does not change. The number moves, but the kidney is fine. It is like reading heavier on a scale while holding a bag of groceries.
Should I stop creatine before a blood test?
Talk to your doctor rather than making the change on your own. The more useful step is to tell your physician you take creatine so the creatinine result is interpreted correctly. If a precise kidney number is needed, ask about a cystatin C test, which is not affected by creatine and sidesteps the issue entirely.
Does creatine cause fat loss or boost testosterone?
No. The viral claim that creatine shrinks fat cells by 30% is not supported by human evidence, and reliable trials do not show a meaningful testosterone change. Creatine's real, evidence-backed benefits are muscle, strength, and modest cognitive support, especially in older adults.
What form of creatine is best?
Plain creatine monohydrate. It is the cheapest and most studied form. The expensive blends that advertise better absorption do not offer a proven advantage, and mega-doses are not better because muscles can only hold a finite amount.
Is creatine safe for the kidneys?
In the available evidence, creatine does not reduce measured kidney filtration (GFR) in people with normal kidney function, even though it can raise the serum creatinine number on a standard lab. If you have existing kidney disease, discuss any supplement with your physician before starting, and use cystatin C if a precise kidney function number is needed.
References
• Chilibeck PD, Kaviani M, Candow DG, et al. (2017). Effect of creatine supplementation during resistance training on lean tissue mass and muscular strength in older adults: a meta-analysis. Open Access Journal of Sports Medicine, 8, 213-226. [VERIFY DOI against PubMed before publish]
• Prokopidis K, Giannos P, Triantafyllidis KK, et al. (2023). Effects of creatine supplementation on memory in healthy individuals: a systematic review and meta-analysis of randomized controlled trials. Nutrition Reviews, 81(4), 416-427. [VERIFY DOI]
• Forbes SC, et al. (2024). Creatine supplementation and cognitive performance: a systematic review and meta-analysis. Frontiers in Nutrition. [VERIFY exact citation, authors, volume, and DOI]
• de Souza E Silva A, et al. (2025). Effect of creatine supplementation on kidney function: a systematic review and meta-analysis. BMC Nephrology. [VERIFY exact citation, authors, volume, and DOI]
• Kreider RB, Kalman DS, Antonio J, et al. (2017). International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. Journal of the International Society of Sports Nutrition, 14, 18. https://doi.org/10.1186/s12970-017-0173-z
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Watch Next
Creatine is one reason a creatinine result can mislead, but it is not the only one. This video covers why creatinine is really a muscle test, when it gives the wrong picture of your kidneys, and the more accurate test (cystatin C) to ask your doctor for. Watch this next.
This article is for educational purposes only and is not medical advice. Always consult your healthcare provider for individual care. The views expressed are Dr. Hashmi's own and do not represent his employer.
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