Creatine Timing: Before or After Workout? What the Studies Show

Why Timing Might Matter

The theoretical case for timing creatine around exercise rests on two physiological observations. First, resistance exercise acutely increases blood flow to working muscles, which could enhance creatine delivery to muscle tissue. The creatine transporter (SLC6A8) is expressed on the sarcolemma of skeletal muscle fibers, and increased perfusion means more plasma creatine passes through the capillary bed per unit time. Second, exercise may upregulate creatine transporter activity. Contraction-induced signaling, including AMPK activation and increased sodium/potassium ATPase turnover, may transiently increase the capacity of muscle fibers to import creatine from the extracellular space.

These mechanisms are plausible but their magnitude is uncertain. Creatine uptake into muscle is a slow process relative to the acute exercise window. The half-life of plasma creatine after a single oral dose is several hours, meaning that creatine is available for muscle uptake long after the post-exercise period of enhanced blood flow subsides. The question is whether the marginal increase in uptake during the peri-workout window produces meaningfully different outcomes over weeks and months of supplementation.

Antonio and Ciccone 2013: The Primary Direct Comparison

The most frequently cited study on creatine timing is by Antonio and Ciccone (2013), published in the Journal of the International Society of Sports Nutrition. This randomized, controlled trial assigned 19 recreational male bodybuilders to one of two groups: creatine immediately before exercise (PRE) or creatine immediately after exercise (POST). Both groups consumed 5 g of creatine monohydrate on training days (five days per week) for four weeks while following a standardized resistance training program.

The results showed a trend favoring post-exercise supplementation. The POST group gained more lean mass (0.4 kg more than PRE, though neither group was compared to placebo) and showed greater improvements in bench press 1RM. However, the between-group differences did not reach conventional statistical significance (p > 0.05) for most outcome measures. The study's primary limitation was its small sample size (n = 19), which severely limited statistical power to detect small between-group differences.

The authors cautiously concluded that post-exercise creatine supplementation may be superior to pre-exercise supplementation for improving body composition and strength, but acknowledged that larger trials were needed to confirm this finding.

Candow et al. 2014: Aging Population Data

Candow et al. (2014) examined creatine timing in an older adult population (50-71 years old), comparing pre-exercise creatine, post-exercise creatine, and placebo groups during a 32-week resistance training program. Published in the Journal of Sports Medicine and Physical Fitness, this study used a dose of 0.1 g/kg/day of creatine monohydrate.

Both creatine groups showed improvements in lean mass, strength, and bone mineral density compared to placebo. However, there were no significant differences between the pre-exercise and post-exercise creatine groups for any outcome measure. The longer study duration (32 weeks vs. 4 weeks in Antonio and Ciccone) and larger sample size provided more statistical power, yet no timing effect emerged.

This null finding is arguably more informative than the suggestive trend in the Antonio and Ciccone study. Over eight months of training and supplementation, any real timing effect should have accumulated to detectable levels. Its absence suggests that the timing of creatine ingestion has minimal practical relevance for long-term outcomes.

Additional Timing Studies

Cribb and Hayes (2006) compared a supplement containing creatine, protein, and carbohydrate taken immediately before and after exercise versus the same supplement taken at times remote from exercise (morning and evening). The peri-exercise group showed greater increases in lean mass, fiber cross-sectional area, and strength. However, this study confounded creatine timing with protein and carbohydrate timing, making it impossible to attribute the observed differences specifically to creatine.

Forbes and Candow (2018) conducted a meta-analysis examining the effects of creatine timing on lean mass and upper-body strength. Their analysis, which pooled data from the available direct comparison studies, found no statistically significant difference between pre-exercise and post-exercise creatine supplementation for either outcome. The pooled effect sizes were small and the confidence intervals broad, reflecting both the limited number of studies and the small between-group differences observed.

Candow et al. (2022) further contributed to this literature with a study comparing creatine supplementation on training days only versus rest days only. Both protocols produced similar outcomes, suggesting that the specific day of ingestion (let alone the specific time) may be less important than cumulative daily intake over the supplementation period.

Effect Sizes in Context

To evaluate the practical significance of creatine timing, it is useful to consider the effect sizes involved. Creatine supplementation itself (versus placebo) produces moderate to large effect sizes for lean mass gain (Cohen's d approximately 0.3-0.5) and strength improvement (d approximately 0.2-0.6) depending on the population and training status. These are meaningful, consistently replicated effects.

The timing-specific effect sizes, where detectable at all, are small. The Antonio and Ciccone data suggest a Cohen's d of approximately 0.1-0.2 for the POST versus PRE comparison. Effect sizes of this magnitude are below the threshold of practical significance for most individuals and are easily obscured by normal training variability, dietary fluctuations, and measurement error.

Put differently: taking creatine at all produces a detectable performance benefit. Taking creatine at a specific time relative to exercise produces, at most, a very small additional benefit that has not been consistently replicated and may not be statistically real.

The Saturated Pool Argument

A fundamental pharmacological argument undermines the importance of acute timing. Creatine's ergogenic effects depend on the chronic elevation of intramuscular phosphocreatine stores, not on acute plasma creatine levels during a single training session. Once the intramuscular pool is saturated (which occurs after loading or several weeks of daily supplementation), the daily dose serves to replace turnover losses, not to acutely fuel that day's workout.

The phosphocreatine used during a workout was already present in the muscle before the session began. It was deposited there over the preceding days and weeks of supplementation. The creatine ingested immediately before or after a workout does not become available as intramuscular phosphocreatine during that session. Absorption from the gut takes approximately 60-90 minutes to peak in plasma, and muscle uptake from plasma is a gradual process that occurs over hours. The acute dose taken peri-workout is essentially a contribution to tomorrow's (or next week's) muscle creatine pool, not today's.

This logic suggests that timing is mechanistically unlikely to matter once stores are saturated. Any timing effect, if real, would need to operate through a mechanism other than acute substrate availability, such as a transient increase in transporter activity that improves the efficiency of daily replenishment. While possible, this mechanism has not been directly demonstrated in humans.

Rest Day Supplementation

The question of timing on rest days is straightforward. On non-training days, there is no peri-exercise window. The daily dose can be taken at any convenient time. Some practitioners recommend taking creatine with a meal on rest days to ensure consistent daily intake and to take advantage of any insulin-mediated enhancement of uptake (discussed in the companion article on creatine with carbs or protein). However, there is no direct evidence that rest-day timing affects outcomes.

The most important factor on rest days is simply remembering to take the dose. Consistent daily intake maintains the elevated intramuscular pool. Skipping rest-day doses means that turnover losses accumulate without replacement, gradually depleting stores. This effect is small on any given day but compounds over weeks of inconsistent use.

Consensus View

The current scientific consensus, as reflected in the 2017 ISSN position stand (Kreider et al., 2017), does not specify a preferred timing for creatine supplementation. The position stand recommends 3-5 g/day of creatine monohydrate and notes that timing relative to exercise has not been conclusively shown to affect outcomes. The emphasis is on consistent daily intake.

If pressed to make a recommendation beyond "take it daily," the slight trend in the Antonio and Ciccone data would favor post-exercise timing. This is also the most practical approach for many users, as it can be combined with a post-workout protein shake. However, this recommendation carries low confidence and should not be treated as a meaningful optimization.

Practical Recommendations

1. Take 3-5 g of creatine monohydrate daily at whatever time is most convenient and sustainable for consistent use.
2. If choosing between immediately before and immediately after exercise, the available evidence provides a very slight signal favoring post-exercise timing. The effect, if real, is small.
3. On rest days, take the dose at any time. With a meal is convenient but not required.
4. Do not stress about timing. Consistent daily intake is the primary variable that determines creatine's effectiveness. Missing the post-workout window but still taking the dose later in the day is vastly preferable to skipping the dose entirely.
5. Creatine taken pre-workout does not acutely fuel that workout. The phosphocreatine used during exercise was already stored in the muscle from prior days of supplementation.

Summary

The evidence for a meaningful timing effect of creatine supplementation is weak. The one direct comparison study (Antonio and Ciccone, 2013) showed a non-significant trend favoring post-exercise timing, while the longer and more statistically powered Candow et al. (2014) study found no timing difference. Meta-analytic data confirms that the effect, if present, is very small. The pharmacological reality that creatine operates through chronic saturation of intramuscular stores — not acute substrate delivery — further argues against the importance of timing. Consistent daily intake of 3-5 g is the evidence-based recommendation; the specific time of day is a minor detail.

Bibliography

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