Creatine Dosage for Older Adults: What the Research Shows

Why Muscle Loss After 50 Matters

Look at a cross sectional scan of the thigh from a sedentary person in their seventies and the change is hard to miss. The pale band of muscle that dominates a young thigh has thinned dramatically, replaced by fat and connective tissue. Dr Scott Forbes, an exercise physiologist at Brandon University in Canada, opens his presentation on creatine and aging with exactly this image, because it captures what is at stake. Less muscle means less strength, and less strength eventually means difficulty climbing stairs, carrying groceries, getting up from a chair, and living independently.

This progressive loss of muscle and function has a clinical name, sarcopenia, and it is common. In the introduction to their published meta analysis, Forbes and colleagues note that roughly one in ten adults aged 60 and over meets the criteria, and that it is closely tied to osteoporosis, frailty and poorer quality of life.

Forbes is clear about the first line response. The most potent tool we have, he explains, is resistance training: go to the gym, lift weights, put them down, repeat. That view is not controversial. The National Strength and Conditioning Association’s position statement on resistance training for older adults concludes that countering muscle disuse through progressive resistance training is a powerful intervention against the loss of strength and mass, frailty, and their consequences for mobility and independence (Fragala et al., 2019). A meta analysis of adults over 50 confirmed that resistance exercise reliably increases lean body mass across a wide range of programs (Peterson et al., 2011).

The question Forbes set out to answer is what happens when you add creatine to that training, and specifically how much creatine older adults need, whether they should load, and whether they can get away with taking it only on the days they lift.

How Creatine Works in Muscle

Before getting to the dosing data, it helps to understand what creatine actually does, and Forbes walks through the basics quickly.

The body makes creatine from three amino acids: arginine, glycine and methionine. Forbes attributes this synthesis to the liver and kidneys. The International Society of Sports Nutrition position stand describes the process as occurring primarily in the liver and pancreas, with the kidney producing an intermediate compound (Kreider et al., 2017), so the accounts are compatible. Once made, about 95% of the body’s creatine ends up in skeletal muscle, and roughly two thirds of that is stored as phosphocreatine.

Phosphocreatine is the point of all this. When a muscle contracts hard, it burns through ATP faster than the mitochondria can replace it. Phosphocreatine hands its phosphate group to ADP and regenerates ATP almost instantly, which is what allows a few seconds of maximal effort. Forbes explains that a bigger phosphocreatine reserve is the primary reason creatine supplementation, combined with training, produces bigger and stronger muscles.

Creatine is also continuously lost. Forbes puts the figure at about two grams per day, converted without any enzyme into creatinine and excreted in urine. The ISSN puts daily turnover at one to two percent of the total pool, which works out to about one to three grams that must be replaced from food or internal synthesis (Kreider et al., 2017). Meat and fish supply roughly half of that in a typical omnivorous diet.

Supplementing raises the total muscle creatine pool by around 20%. Forbes describes the two classic ways of getting there. You can take a loading dose, usually 20 grams per day split into several servings for five to seven days, and then drop to a maintenance dose. Or you can simply take about three grams per day for roughly four weeks. He credits the original work to Roger Harris and Eric Hultman, and the research bears this out. Hultman’s 1996 study found that six days at 20 grams per day raised muscle total creatine by about 20%, that two grams per day maintained it, and that three grams per day reached the same 20% rise over 28 days without any loading (Hultman et al., 1996). Once supplementation stopped, levels drifted back to baseline within about a month.

That study, and most like it, was conducted in healthy young men. Forbes returns to this point later, because it turns out to matter.

Beyond Energy: Other Ways Creatine May Help

Forbes is careful to say that phosphocreatine is not the whole story. He lists several additional mechanisms, and it is worth separating what is well supported from what remains a working hypothesis.

Glycogen retention is one. According to Forbes, creatine increases the amount of glycogen stored in muscle, which raises exercise capacity and allows harder training sessions that compound into more growth over time. Human evidence supports the first half of that chain. In a controlled study of 14 men, five days of creatine alongside a high carbohydrate diet produced greater muscle glycogen storage than carbohydrate alone, an effect visible within the first 24 hours of recovery (Roberts et al., 2016). Whether that extra glycogen translates into meaningfully harder resistance training in older adults has not been directly tested.

Antioxidant effects are another. Forbes suggests creatine helps shuttle ATP from the mitochondria, where it is produced, to the sites where it is used, and that this reduces oxidative stress. The supporting studies here are small, mostly in young athletes measuring markers of oxidative damage after intense exercise, and none were done in older adults. This is best considered preliminary.

Forbes also highlights work by Darren Burke and Darren Candow in the 2000s showing that creatine raises insulin like growth factor 1 (IGF-1), an anabolic hormone that signals through the mTOR pathway to promote muscle growth. The underlying trial deserves a closer look. Eight weeks of resistance training raised muscle IGF-1 content by 67% overall, and the rise was larger with creatine (78%) than with placebo (54%). However, the difference between groups reached p = 0.06, just short of conventional statistical significance, and the participants were young adults (Burke et al., 2008). The direction of the effect fits Forbes’s account, but it is a lean piece of evidence to hang a mechanism on.

Then there is water. Forbes cites Mark Tarnopolsky’s group at McMaster University in describing how creatine draws water into the muscle cell, and how that swelling acts as a growth signal, switching on myogenic regulatory factors that activate satellite cells. Satellite cells are the muscle’s resident stem cells; when they mature into new myonuclei, the fibre gains capacity to grow. The cell swelling part is well founded, since creatine is osmotically active and is transported into muscle with sodium, pulling water along (Antonio et al., 2021). The satellite cell part has direct human support: in a 16 week heavy training study, young men taking creatine showed a larger increase in satellite cells and myonuclei than those on placebo or protein (Olsen et al., 2006). What remains a hypothesis is that the swelling itself is the trigger.

Finally, Forbes mentions animal evidence that creatine can inhibit myostatin, a protein that acts as a brake on muscle growth. The picture here is mixed. There is at least one human trial in young men that examined serum myostatin during eight weeks of resistance training with and without creatine (Saremi et al., 2010), so the evidence is not limited to animals. On the other hand, a 2023 study in resistance trained rats found that training lowered myostatin but adding creatine made no further difference (de Carvalho et al., 2023). This mechanism should be considered unresolved.

The honest summary is that creatine almost certainly works through more than one route, that increased phosphocreatine is the best established of them, and that the others range from plausible to speculative.

Why Older Adults May Need a Different Approach

Here Forbes makes the observation that motivates the rest of his work. The dosing studies that established the 20% rule were done in young people. Older adults, he explains, start with lower phosphocreatine levels in their muscle, particularly in the vastus lateralis, the large muscle on the outer thigh. It follows, he suggests, that they may need more creatine than younger adults to see the same benefit, especially in the lower body.

The premise is supported by independent research. A study using magnetic resonance spectroscopy in older adults found that resting phosphocreatine was positively associated with muscle volume and knee extensor power, and that older adults meeting sarcopenia criteria had lower phosphocreatine than those who did not (Hinkley et al., 2020). In their paper, Forbes and colleagues add that lower body muscles lose more strength with age than upper body muscles, which they attribute to atrophy of fast twitch fibres, less high intensity activity, and lower meat intake.

Whether lower stores translate into a higher dose requirement is a reasonable inference rather than a tested finding. That distinction is important, and it is why Forbes turned to the existing trials to look for patterns.

What the 2021 Meta Analysis Examined

By early 2021, twenty randomized trials had combined creatine with resistance training in adults over 50 and measured lean tissue mass or strength. Forbes describes these as a mixed bag. Some used a loading phase and some did not. Some used a maintenance dose of five grams per day or less, typically three to five grams. Others used relative dosing based on body weight, usually 0.1 grams per kilogram per day, which works out to roughly seven to nine grams per day for most people.

Forbes and his coauthors, Darren Candow, Sergej Ostojic, Michael Roberts and Philip Chilibeck, had three goals. First, update the earlier meta analyses. Forbes mentions three: one from Stuart Phillips’s group in 2014 (first authored by Michaela Devries), one Forbes published with Candow and Chilibeck the same year, and a 2017 update led by Chilibeck. All three concluded that creatine added about 1.2 to 1.3 kilograms of lean tissue on top of what training alone produced. The 2017 analysis, for example, pooled 22 studies and 721 participants and found a 1.37 kilogram advantage for creatine, along with greater chest press and leg press gains (Chilibeck et al., 2017). Second, test whether low and high dose strategies, with or without loading, produced different results. Third, examine the handful of trials in which participants took creatine only on the days they trained.

The inclusion rules were strict: randomized controlled trials only, participants with a mean age over 50, creatine plus resistance training compared against placebo plus resistance training, at least five weeks long, and a measurement of whole body lean tissue, chest press strength, or leg press strength. The authors used a fixed effects model and checked funnel plots for publication bias, finding none.

Muscle Mass: Dose Made Little Difference

Forbes describes the lean tissue results with a forest plot. Each study is a line, and a diamond summarises the pooled effect. If the diamond sits to the right of the vertical line, creatine won.

For lean tissue mass, every diamond sat to the right. Across 16 trials with 18 treatment arms and 509 participants, creatine plus training added an average of 1.32 kilograms more lean tissue than placebo plus training, with a 95% confidence interval of 0.93 to 1.72 kilograms (Forbes et al., 2021). That is very close to the earlier estimates, which suggests the finding is stable as more studies accumulate.

The subgroups told the same story. Studies using five grams per day or less produced a 1.40 kilogram advantage. Studies using more than five grams produced a 1.21 kilogram advantage. When the authors removed every trial that included a loading phase, both groups still favoured creatine; in fact, the low dose estimate rose to 1.81 kilograms.

Forbes’s conclusion is that low and high dose strategies, with and without loading, were equally effective for building lean tissue in older adults. He notes this should not surprise anyone familiar with the Harris and Hultman work, since both routes get muscle creatine to the same place. One caution the authors raise in the paper: no trial in the set directly compared a low dose with a high dose in the same study, and every high dose trial used relative dosing while every low dose trial used a fixed daily amount. The subgroup comparison is therefore indirect, and a head to head trial would settle it more convincingly.

It is also worth noting what lean tissue mass measures. Techniques such as dual energy X ray absorptiometry count everything that is not fat or bone, including water. Because creatine draws water into muscle cells, some of the early gain reflects hydration rather than new contractile protein. The 2021 ISSN review addresses this directly and concludes that the extra water is intracellular and largely transient, and that longer studies still show genuine gains in muscle size and function (Antonio et al., 2021). But readers should picture the 1.3 kilogram figure as lean tissue, not pure muscle fibre.

Strength: Where Dose and Loading Start to Matter

This is the part Forbes says he gets excited about, and it is where the story gets more nuanced.

For leg press strength, the overall analysis across 15 trials and 426 participants favoured creatine, but only just. The standardised mean difference was 0.20 and the confidence interval reached exactly zero, with p = 0.05 (Forbes et al., 2021). In plain terms, the average effect on lower body strength was small and borderline.

The subgroups explain why. Forbes explains that the low dose studies, three to five grams per day, showed no benefit for leg press strength at all. Only the high dose studies did, with a standardised mean difference of 0.29. And when the authors excluded the high dose studies that began with a loading phase, the high dose effect dropped to nonsignificant (p = 0.12).

Forbes interprets this as evidence that older adults who want stronger legs need both a loading phase and a maintenance dose above five grams per day. His practical framing is memorable: if you are an older adult and you just want bigger muscles, a higher dose does not appear necessary; if you want the lower body strength benefits, a higher dose may be required. He connects this back to the lower phosphocreatine stores in the vastus lateralis, arguing that the legs simply need more creatine to reach an effective level.

The published paper adds a wrinkle that the presentation did not have time for. For chest press strength, the pattern was almost reversed. Loading followed by a lower dose produced a significant benefit, while higher dose creatine did not differ from placebo when all studies were included. That null result depended heavily on a single 52 week trial in which both the creatine and placebo groups gained enormous amounts of upper body strength; when it was removed in a sensitivity analysis, the higher dose result became significant too. The authors’ overall reading is that a loading phase appears important for strength gains in general, and that the ideal maintenance dose may differ between upper and lower body.

A few cautions are in order. These subgroup analyses rest on small numbers of studies, sometimes only two or three, so each estimate is imprecise. The trials themselves averaged just 34 participants. Strength effects were measured as standardised differences, which are harder to translate into kilograms on a bar than the lean mass figures. And the most recent independent meta analysis, which pooled 20 trials and 1,093 older adults through August 2024, found creatine plus exercise improved one repetition maximum strength by about 2.1 kilograms on average, but did not analyse dosing strategy separately (Sharifian et al., 2025). The dosing conclusions from the Forbes analysis remain the best available guidance, but they are a starting hypothesis, not a settled rule.

Taking Creatine Only on Training Days

The third question is one Forbes says he is asked constantly: can you skip creatine on rest days?

Four of the twenty trials had participants take creatine only on the days they lifted, and Forbes notes that most were run by Darren Candow at the University of Regina. Pooling them, creatine on training days alone still beat placebo on every measure: lean tissue mass by about 1.73 kilograms, chest press strength with a standardised mean difference of 0.58, and leg press strength at 0.44 (Forbes et al., 2021). Those effect sizes are, if anything, larger than in the full analysis, though with fewer studies the confidence intervals are wider.

Forbes concludes that training day only creatine is an effective strategy. The paper offers some context on why it might work. In every one of these trials, participants took their creatine within about an hour after the training session, and earlier research has shown that muscle contraction increases creatine uptake, likely by activating the creatine transporter. The authors also point out a practical advantage: people may find it easier to stick with a supplement they only take on gym days.

What the data cannot yet tell us is whether this approach is as good as daily dosing. Forbes is explicit that no study has compared the two head to head. It is also worth remembering that the training day only trials used relatively high doses on those days, around 0.1 grams per kilogram, so the weekly total was not trivial. An older adult taking three grams twice a week is not doing what these studies did.

What We Still Do Not Know

Forbes closes his talk with a list of gaps, and it is a useful corrective to any impression that the science is finished.

There are no dose response studies in older adults, meaning trials that give different groups different amounts and watch what happens. There is no single trial that directly compares a low and a high dose. There is no trial comparing training day only creatine with daily creatine. Nobody has properly tested cycling on and off creatine against continuous use, even though people ask about it constantly. And the dose that matters for muscle may not be the dose that matters for other tissues; Forbes specifically names brain health, bone health and mitochondria as areas needing their own dosing work.

The bone question has some newer data. The 2025 meta analysis found that creatine plus exercise had no significant effect on total body bone mineral density in older adults (Sharifian et al., 2025), which tempers some of the enthusiasm in earlier narrative reviews. Brain outcomes were outside the scope of the Forbes analysis and deserve a separate article.

On safety, the trials in the meta analysis were reassuring. Most reported no adverse events. A few recorded isolated gastrointestinal upset, more often during loading, and two reported muscle cramps that occurred at similar rates in the creatine and placebo groups (Forbes et al., 2021). The broader literature reviewed by the ISSN finds creatine monohydrate well tolerated at three to five grams per day or 0.1 grams per kilogram (Antonio et al., 2021). Anyone with kidney disease, or taking medications that affect the kidneys, should discuss creatine with their doctor before starting, since creatine raises blood creatinine and can complicate the interpretation of routine kidney tests.

One more point of transparency. Forbes discloses that he has served as a scientific adviser to a company that sold creatine, and Candow sits on the advisory board of a creatine manufacturer. These disclosures do not invalidate the analysis, which uses published data anyone can check, but readers of any supplement research deserve to know about them.

What This Means in Practice

Pulling the threads together, here is what the evidence supports for an older adult who is already doing, or about to start, resistance training.

Creatine plus lifting reliably adds lean tissue. Across five meta analyses spanning a decade, the estimate has hovered around 1.2 to 1.4 kilograms more than training alone. This is the strongest finding in the field, and for lean mass the dose does not appear to matter much. Three to five grams a day, taken consistently, is enough.

Strength gains are real but smaller, and here the dosing strategy may matter. Forbes’s analysis suggests a loading phase of about 20 grams per day for five to seven days improves the odds of a strength benefit, and that for lower body strength a maintenance dose above five grams per day, roughly 0.1 grams per kilogram of body weight, may be needed. Treat this as a reasonable working recommendation drawn from indirect comparisons rather than a proven threshold.

Taking creatine only on training days worked in the available trials, especially when taken soon after the session. If daily dosing is a barrier, this is a legitimate alternative, though nobody has yet shown it matches daily intake.

None of this replaces the training. Forbes is emphatic that resistance training is the intervention, and creatine is the addition that makes it work somewhat better. An older adult who lifts twice a week without creatine will do far better than one who takes creatine and does not lift.

The remaining questions are genuine, and the dosing subgroups in particular will be revised as direct comparison trials appear. But the central claim of Forbes’s presentation, that creatine combined with resistance training helps older adults build and keep muscle, rests on a consistent and growing body of randomized evidence.