Creatine has an image problem for the audience it might most benefit. It is filed mentally alongside bodybuilding, protein tubs and men in their twenties — which is unfortunate, because the population with the most to gain from it is people in their sixties and seventies who have never set foot in a gym.
It is also, by some distance, the most studied supplement in existence. Hundreds of trials over three decades. That alone separates it from almost everything in the longevity category, where the usual complaint is that human data barely exists.
What it does
Creatine is not a hormone or a stimulant. It is a compound your body already makes — in the kidneys and liver, from arginine and glycine — and which you also get from meat and fish, at roughly 1–2 g a day in an omnivorous diet.
Its job is energy buffering. Muscle stores creatine as phosphocreatine, which donates a phosphate group to rapidly regenerate ATP, the cell’s immediate energy currency. When you need a burst of power lasting seconds — standing up, climbing stairs, catching yourself mid-stumble, or a heavy set of eight — phosphocreatine is what supplies it.
Supplementation increases muscle phosphocreatine stores. More stored, more work available before fatigue.
Vegetarians and vegans start with lower stores, because dietary creatine comes from animal foods, and tend to show larger responses.
The muscle evidence
This is the strongest part, and the picture is nuanced rather than uniformly positive.
Meta-analyses consistently find that creatine combined with resistance training augments gains in lean tissue mass and strength in older adults compared with training plus placebo. But heterogeneity between studies is substantial: in one review of 20 trials, ten showed benefit and ten found no advantage over placebo.
The effect sizes on direct measures of muscle thickness are small — a pooled estimate around 0.11 standardised units, with the credible interval spanning zero, and slightly larger benefits in younger than older adults.
So the honest framing is: creatine is an amplifier, not an intervention. It makes resistance training somewhat more productive. It does not build muscle in someone who is not training, and the increment is modest.
The consistent thread across the literature is that the pairing matters. Creatine plus training beats training alone. Creatine alone does very little.
Where it gets more interesting
Two areas beyond muscle deserve mention, with different levels of confidence.
Cognition. The brain is metabolically expensive and uses the same phosphocreatine system. Reviews of creatine and cognition in older adults find suggestive but inconsistent results, with the more promising signals appearing in states of metabolic stress — sleep deprivation, mental fatigue — and in vegetarians, who start with lower stores. This is an active research area, not a settled finding, and it should not be the reason you buy creatine.
Bone. A plausible hypothesis held that more muscle pulling on bone during training would increase bone density. A meta-analysis of creatine during resistance training in older adults found no greater increase in bone mineral density than training alone. Worth stating because the claim still circulates.
Safety
Creatine’s safety record is unusually well characterised, which is what happens when a compound is studied for thirty years.
The kidney concern is the one people raise, and it stems from a misreading. Creatine raises blood creatinine — a breakdown product, and the standard marker used to estimate kidney function. Higher creatinine on a blood test can look like impaired kidney function when it simply reflects supplementation. In studies of older adults, plasma creatinine rose while creatinine clearance — the actual measure of filtration — did not change.
In healthy individuals, the current evidence does not indicate harmful effects on kidney function.
Two practical notes. If you have existing kidney disease, this is a conversation for your doctor, not an article. And if you have a blood test coming up, mention that you take creatine, so a raised creatinine is not misread.
The other common complaint is water retention — creatine draws water into muscle cells, typically producing 1–2 kg of weight gain in the first weeks. That is intracellular water, not fat.
How to take it
The protocol is simpler than the marketing suggests.
Creatine monohydrate, 3–5 g daily. That is it. Monohydrate is the form nearly every study used, and it is the cheapest. The alternative forms — hydrochloride, buffered, ethyl ester — cost more and have not demonstrated superiority.
A loading phase is optional. Meta-analysis of ingestion strategies found creatine augments lean mass and strength independent of dosing strategy. Loading with 20 g a day for a week saturates stores faster; taking 5 g daily gets to the same place in about a month.
Timing does not matter much. Take it whenever you will remember. Consistency beats scheduling.
It needs to be ongoing. Stop, and stores return to baseline over several weeks.
Look for a product that specifies creatine monohydrate, ideally Creapure-labelled. It is one of the cheapest supplements available — a year’s supply costs less than a month of most longevity compounds.
Why it belongs in this section
Set creatine against the compounds in the longevity supplement article and the contrast is instructive.
NMN, spermidine and fisetin are sold on mechanism and animal data, with human evidence that is thin, short and mostly limited to biomarkers. Creatine has thirty years of human trials, hundreds of studies, meta-analyses in the population that matters, and a characterised safety profile — and it is largely ignored by the longevity market because it is cheap, unpatentable and associated with gym culture.
That said, the honest verdict is measured. The effects are modest, they depend on doing resistance training, and the cognitive claims are not yet established.
The reason it earns a place here is what it acts on. Muscle mass and strength determine independence in later life, grip strength predicts mortality better than blood pressure, and the decline starts decades before anyone notices. Creatine makes the intervention that addresses that — resistance training — somewhat more effective, for around £30 a year, with a safety record almost nothing else in this category can claim.
Modest, cheap, well-evidenced and slightly boring. That describes most of what actually works.
This article is for general information and is not medical advice. If you have kidney disease or take medication affecting kidney function, speak to your GP before supplementing.
Sources
- Forbes SC, Candow DG, et al. Meta-analysis examining the importance of creatine ingestion strategies on lean tissue mass and strength in older adults. Nutrients, 2021;13(6):1912. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8229907/
- The impact of creatine supplementation associated with resistance training on muscular strength and lean tissue mass in the aged: a systematic review and meta-analysis. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12752335/
- The effects of creatine supplementation combined with resistance training on regional measures of muscle hypertrophy: a systematic review with meta-analysis. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10180745/
- Creatine and cognition in aging: a systematic review of evidence in older adults. https://pmc.ncbi.nlm.nih.gov/articles/PMC12793482/
- Candow DG, et al. Creatine supplementation during resistance training does not lead to greater bone mineral density in older humans: a brief meta-analysis. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5928444/
- Tarnopolsky M, et al. Creatine monohydrate and conjugated linoleic acid improve strength and body composition following resistance exercise in older adults. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1994592/
This article is for general information and is not medical advice. If a health problem is affecting your daily life, speak to your GP.
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