The science of creatine, and why electrolytes are part of the same story.
Creatine is one of the most studied supplements in sports nutrition. But most of what gets sold alongside it skips a real, underexplored piece of the picture: creatine doesn't just get "taken" into your cells, it's actively transported, using a system built on sodium and chloride.
That's the mechanism this page walks through. It's also why Rephora Labs™ builds creatine and a full electrolyte formulation into one formula, instead of treating them as separate products.
Your cells don't just absorb creatine. They transport it.
Creatine crosses into muscle and brain cells through a dedicated transporter protein, CreaT (SLC6A8), that is sodium- and chloride-dependent by design.1 This is basic, well-established physiology, confirmed by research on the human intestinal creatine transporter going back over two decades.
It's a detail most creatine products don't build around. Rephora Labs™ does, every stick pack pairs creatine with IonGate™, our proprietary sodium, potassium, magnesium, and chloride formulation, matched to the same system the transporter relies on.
The core benefits, substantiated.
Creatine is one of the most studied supplements in sports nutrition. The evidence below is not sex-specific in most cases, but the research on strength training, muscle preservation, and bone health has been run separately in women's and men's cohorts. Presented as it was studied.
Builds lean muscle and strength, when combined with resistance training13
Helps preserve lean mass during and after menopause13
May help preserve hip bone density post-menopause; not consistent across all trials14,15
Supports memory and processing speed8,9
Early evidence: helps preserve cognitive performance during sleep deprivation, e.g. for shift workers or new parents18
Builds lean muscle and strength, when combined with resistance training16
Improves power output during short, high-intensity exercise16
Helps preserve muscle mass with age17
Supports memory and processing speed8,9
Early evidence: helps preserve cognitive performance during sleep deprivation, e.g. for shift workers or new parents18
14 Chilibeck et al., 2015, Medicine & Science in Sports & Exercise; 2-year follow-up, 2023: postmenopausal women on creatine lost significantly less hip bone density than placebo.
15 Most recent pooled meta-analysis across all trials did not find a statistically significant overall bone-density effect.
16 Lanhers et al., 2015, Sports Medicine: meta-analysis of RCTs found creatine supplementation with resistance training increased maximal strength and power output versus training alone.
17 Devries & Phillips, 2014, Journal of Food Science meta-analysis: creatine plus resistance training increased lean tissue mass in older adults versus training alone.
18 Gordji-Nejad et al., 2024, Scientific Reports; follow-up 2025/2026, Nutrients: a single dose of creatine improved cognitive performance during 21 hours of sleep deprivation, replicated at a second, lower dose. Studied doses (0.2–0.35 g/kg) were higher than a standard daily serving, an early, active research area, not yet a settled claim about everyday use. See Section 06 for detail.
Four electrolytes, and what each one actually does.
Sodium: the ion the creatine transporter runs on. It's also the electrolyte with the most direct backing from sports medicine's own governing body: the American College of Sports Medicine recommends adding sodium to fluid replacement during exercise longer than an hour, both to support rehydration and reduce the risk of exercise-associated hyponatremia.2 Separately, sodium-containing electrolyte intake has been linked to more than 2x longer exercise time before muscle cramp onset compared to dehydration.3
Chloride: co-transported alongside sodium and creatine; helps maintain fluid balance.
Potassium: supports intracellular fluid balance and muscle contraction. In controlled research, potassium supplementation measurably countered sodium-driven fluid retention, in one study, subjects retained significantly less fluid (as measured by body weight) when given potassium alongside a sodium-retention-inducing condition, compared to placebo.4
Magnesium: the required cofactor for creatine kinase, the enzyme that converts phosphocreatine back into usable ATP.
Every stick pack delivers 840 mg sodium, 1,519 mg chloride, 250 mg potassium, and 75 mg magnesium: real amounts, not label dressing.
Matched to the sodium- and chloride-dependent system the creatine transporter runs on, in every stick pack.
3 Jung et al., 2005, Journal of Athletic Training: a sodium-containing electrolyte beverage delayed muscle cramp onset to 36.8 min vs. 14.6 min in a dehydrated control. Delayed onset, not guaranteed prevention.
4 Findling et al., 1993, Kidney International: double-blind, randomized crossover study (n=8), potassium supplementation significantly reduced body weight and increased sodium excretion vs. placebo, in a controlled sodium-retention model. Small sample, and the retention was pharmacologically induced rather than naturally occurring.
Not every electrolyte drink out-hydrates water.
There's a specific, measurable reason why. Research using the Beverage Hydration Index, a standardized method for measuring how much of what you drink is actually retained versus excreted, found that a beverage needs at least 40 mmol/L of sodium to produce a measurably better fluid-retention outcome than water alone.5 Below that threshold, a drink isn't meaningfully out-hydrating water, it's just flavored water.
This math isn't just for the gym, it's the same math behind everyday hydration. Most commercial sports drinks fall short of that number. The leading sports drink, for example, works out to roughly 19.6 mmol/L at its own labeled serving size.6 One stick pack of Rephora Labs™, mixed into 16oz of water, works out to roughly 77 mmol/L, well above the threshold shown to matter.
6 Based on Gatorade Thirst Quencher (Original), the top-selling sports drink by market share: 160mg sodium per 12oz serving per label, standardizing to ~19.6 mmol/L. Rephora Labs™ figure assumes 840 mg sodium in 473ml (16oz) of water, per official mixing instructions.
That's why IonGate™ is built into every stick pack as a daily formula, not just something to reach for around a workout.
Here's what's actually going on.
It's one of the most common reasons people quit creatine, and it's usually not the creatine itself. Training hard means sweating out real amounts of sodium, and low sodium during exercise has a measurable effect: in one controlled study, a sodium-containing electrolyte drink more than doubled the time before muscle cramping set in, compared to a dehydrated control (36.8 minutes vs. 14.6 minutes).3 Bloating and cramping tend to travel together, and both trace back to the same root cause, electrolytes lost in training, not the compound.
That's the case for building sodium into the formula from the start, rather than treating it as optional.
The ions being moved.
Roughly half of the brain's total energy budget goes toward one job: pumping sodium and potassium across neuron membranes so they can fire.7 Creatine's role is keeping the ATP supply available for that process, which means the electrolytes aren't a separate story from cognition, they're the ions actually being moved.
Two independent meta-analyses support creatine's cognitive case: a 2018 review linked it to measurable memory improvements,8 and a larger 2024 review of 16 randomized trials confirmed benefits for memory and processing speed specifically, though it found no significant effect on overall or executive function, worth noting alongside the positive result.9
Separately, hydration status itself has a documented relationship with how your mind feels under pressure. A meta-analysis of 30+ studies found dehydration impairs performance on tasks requiring concentration, though the research is genuinely split, other analyses have found dehydration's clearest, most consistent effect isn't on raw task performance but on mood, perceived effort, and fatigue.10 Either way, staying properly hydrated is part of the same story as staying mentally sharp.
A newer, more specific line of research is worth watching: a single dose of creatine measurably improved cognitive performance during 21 hours of sleep deprivation, with the effect replicated at a second, lower dose in follow-up work.11 The doses studied were higher than a standard daily serving, this is an early, active research area, not yet a settled claim about everyday use.
8 Avgerinos et al., 2018, Experimental Gerontology.
9 Xu et al., 2024/2025, Frontiers in Nutrition (16 RCTs).
10 Wittbrodt & Millard-Stafford, 2018, Medicine & Science in Sports & Exercise (meta-analysis of 30+ studies, found cognitive impairment from dehydration). Contrast: Goodman, Moreland & Marino, 2019, Physiology & Behavior (found no significant cognitive impairment, but consistent mood effects). The literature is genuinely split on task performance; mood/perceived-effort effects are more consistent across studies.
11 Gordji-Nejad et al., 2024, Scientific Reports; follow-up 2025/2026, Nutrients. Studied doses (0.2–0.35 g/kg) were higher than a standard daily serving.
Being specific rather than rounding up.
Creatine research has historically underrepresented women. That's shifting. A 2025 review mapped what's currently known across menstruation, pregnancy, and menopause.12 The strength of the evidence varies by outcome, and it's worth being specific rather than rounding up:
Lean mass and strength: well-supported. A 2025/2026 systematic review of 7 randomized trials in postmenopausal women (n=608) found meaningful gains in lean mass and strength when creatine was combined with resistance training.13
Bone density: promising in individual research, not yet consistent overall. A 12-month trial found postmenopausal women on creatine lost significantly less hip bone density than placebo,14 with a 2-year follow-up from the same research group. But when the full body of trials is pooled, the most recent systematic review did not find a statistically significant overall effect on bone density.15
Perimenopause and pregnancy remain areas the research itself flags as needing more study.
13 2025/2026 systematic review, 7 RCTs, n=608 postmenopausal women.
14 Chilibeck et al., 2015, Medicine & Science in Sports & Exercise; 2-year follow-up, 2023.
15 Most recent pooled meta-analysis found no statistically significant overall bone-density effect.
Human & Clinical Studies.
The following studies are provided for transparency and scientific context. Studies cited examine specific ingredients, doses, or formulations that may differ from this product and are not claims about this product's tested effects.
Peral et al., 2002, The Journal of Physiology
American College of Sports Medicine, Position Stand: Exercise and Fluid Replacement
Jung et al., 2005, Journal of Athletic Training
Findling et al., 1993, Kidney International
Maughan, Watson & Cordery, 2016, American Journal of Clinical Nutrition
Avgerinos et al., 2018, Experimental Gerontology
Xu et al., 2024/2025, Frontiers in Nutrition
Wittbrodt & Millard-Stafford, 2018, Medicine & Science in Sports & Exercise
Goodman, Moreland & Marino, 2019, Physiology & Behavior
Gordji-Nejad et al., 2024, Scientific Reports (with 2025/2026 follow-up, Nutrients)
Lanhers et al., 2015, Sports Medicine
Devries & Phillips, 2014, Journal of Food Science
Smith-Ryan et al., 2025, Journal of the International Society of Sports Nutrition
2025/2026 systematic review, 7 RCTs (n=608 postmenopausal women)
Chilibeck et al., 2015, Medicine & Science in Sports & Exercise (2-year follow-up, 2023)
The transport system creatine relies on. Built into every formula.
Creatine is one of the most studied supplements in sports nutrition. Rephora Labs™ pairs it with IonGate™, a full sodium, potassium, magnesium, and chloride formulation, matched to the transporter system creatine already depends on, in a single daily stick pack.
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