Creatine occupies an unusual position in the supplement literature. It is inexpensive, it has been studied for three decades, and the gap between what the evidence shows and what the marketing claims is smaller than usual. It is still a gap. For clinicians over 50, who are more likely to be thinking about sarcopenia than about athletic performance, the useful question is specific: what happens when creatine is added to a resistance training program that is actually happening?
What the trials show
Meta-analyses in older adults converge on a modest and consistent result. Participants who combined creatine with resistance training gained more lean tissue mass and improved on some strength measures compared with training alone. The effect sizes are not dramatic. They are also not zero, which separates creatine from most of the shelf.
The second finding is just as consistent: creatine without a training stimulus does very little. The supplement appears to work by supporting the quality and volume of training sessions, not by acting on muscle directly in a resting person. A reader who is not training twice a week has a different first problem to solve.
The practical details
Most trials in older adults used 3 to 5 grams of creatine monohydrate per day. Loading protocols of four to five days reach saturation faster; daily low dosing reaches the same place in roughly three to four weeks. Timing relative to workouts has not been shown to matter in a clinically meaningful way.
On kidney function, the trial literature in healthy adults has not shown harm at studied doses. One laboratory caveat matters for this readership: creatine supplementation raises serum creatinine without changing true glomerular filtration, which can make an estimated GFR look worse than it is. A cystatin C based estimate avoids the confound when the number does not fit the patient.
What remains unproven
Claims about cognition, bone density, and direct anti-aging effects run ahead of the evidence. There are early signals and small trials, and there is a large commercial incentive to read them generously. The board’s standard applies: a signal is a reason to watch the literature, not a reason to change a recommendation.
This article is education about a body of evidence. It is not a recommendation to start, stop, or dose any supplement, and individual decisions belong in a clinical conversation that includes medications, kidney history, and the training program the supplement is supposed to support.
A Spanish version of this article, translated by Lucia Fernandez, appears in the Spanish mirror of Pulso.