Creatine is the single most studied and most reliably effective performance supplement that exists. It increases strength, power output, and how much muscle you can build over time, and it does this by saturating the phosphocreatine energy system in muscle, the system that powers the first 10-15 seconds of every maximal effort. If you lift, sprint, play sports, or do anything involving short bursts of high output, creatine gives you more reps per set, more power per rep, and faster recovery between sets. Those small per-session gains compound into meaningfully more muscle and strength over months.
Creatine also has a meaningful cognitive side. The brain runs on the same phosphocreatine system as muscle, and keeping those stores saturated supports mental performance, particularly memory and reasoning under cognitive load. it increases ATP availability in neurons.
Creatine is also one of the few supplements where the downside risk is essentially zero in healthy people and the upside is consistent across virtually every study ever done on it. It works for men, it works for women, it works for vegetarians (who often see the biggest response because they start with lower baseline stores), it works for older adults, and it works regardless of training style. Decades of safety data across tens of thousands of subjects.
Your body makes roughly 1-2g of creatine daily in the liver and kidneys from the amino acids glycine, arginine, and methionine. You get another 1-2g from dietary meat and fish (red meat and herring are the richest sources). The total is enough to keep muscle creatine stores at roughly 60-80% of their maximum capacity in most people. Supplementation pushes those stores toward full saturation, which is where the performance benefit comes from. Vegetarians and vegans start significantly lower because they're not getting the dietary contribution, and they typically see the largest absolute improvements with supplementation.
deep dive
How it works in the muscle. During any maximal effort, the muscle spends ATP faster than it can regenerate it through glycolysis or oxidative metabolism. Creatine phosphate donates its phosphate group directly to ADP via the enzyme creatine kinase, regenerating ATP almost instantly without needing oxygen or glucose. The size of your phosphocreatine reservoir determines how long this system can run before tapping out. More creatine in the muscle means more phosphate available, which means more reps at maximal output, more power on each rep, and faster recovery between sets. The effect is most pronounced on short, explosive, high-output work: heavy lifting, sprints, jumps, throws. It doesn't meaningfully help steady-state endurance because endurance runs on the oxidative system, which doesn't use phosphocreatine.
Muscle growth. Creatine builds muscle through two mechanisms. First, the direct performance benefit: more reps and more load across sets translates to more mechanical tension over time, which is the primary driver of hypertrophy. Someone who can do 8 reps instead of 6 on their working sets for months will build more muscle. Second, cell volumisation: creatine draws water into muscle cells osmotically, which modestly increases muscle size (typically 1-2 kg of weight gain in the first few weeks, most of it intracellular water) and may create a more favourable signalling environment for protein synthesis. A meta-analysis of 22 trials found creatine supplementation combined with resistance training produced an average 8% greater gain in strength and 14% greater gain in performance compared to training alone.
Cognitive effects. Creatine isn't just a muscle supplement. The brain uses phosphocreatine to regenerate ATP the same way muscle does, and cognitive tasks that demand high energy turnover benefit from saturated brain stores. A systematic review found creatine supplementation improved short-term memory and reasoning in healthy adults, with the largest effects in vegetarians and older adults (the groups most likely to have lower baseline stores). The effect is modest but real. It's also being investigated for depression, traumatic brain injury, and neurodegenerative disease, with early evidence supporting a benefit particularly in women, who appear to show larger cognitive and mood responses than men.
Women specifically. Women have been historically underrepresented in creatine research and there's a persistent myth that creatine is a "male" supplement. The opposite is closer to the truth. Women typically have 70-80% of the muscle creatine stores men have at baseline, meaning they have more headroom to respond to supplementation. Women also show equal or greater gains in strength and lean mass from creatine across studies, and may see larger cognitive and mood benefits. Creatine does not cause virilisation, it's not hormonally active. The water weight gain (1-2 kg of intracellular water in the muscle) is sometimes mistaken for fat gain or bloating but is cosmetically invisible on the body, it's held inside muscle tissue, not under the skin. A review focused on women concluded creatine is particularly beneficial across the lifespan, with specific relevance for postmenopausal women where it supports bone density, muscle mass, and mood alongside resistance training.
What creatine doesn't do. It doesn't cause kidney damage in healthy people, this myth has been studied exhaustively and consistently debunked. It doesn't cause hair loss, the one often-cited 2009 study in rugby players showed a transient DHT increase that has never been replicated and wasn't tied to any actual hair outcomes. It doesn't cause dehydration or cramping, the evidence points the other way (better hydration status in trained athletes). It doesn't suppress natural creatine production permanently, stopping supplementation just drops you back to your baseline within a few weeks. None of these concerns are supported by the actual evidence base.
Dosage
- Standard dose: 5g daily of creatine monohydrate, taken at any time. Timing doesn't meaningfully matter, creatine builds up in muscle over weeks rather than working acutely. Take it whenever is most consistent for you
- Loading protocol (optional): 20-25g per day split into 4-5 doses for 5-7 days, then drop to 3-5g maintenance. This saturates muscle stores faster (within a week instead of 3-4 weeks) but produces the same end result as just taking the maintenance dose from day one. Loading can cause more GI upset, most people skip it and just start at 5g daily
- Bodyweight-adjusted dose: Larger individuals may benefit from the higher end of the range. A practical target is 0.1g per kg of bodyweight, so 8-10g for a 100kg person. Most people do fine on a flat 5g regardless of bodyweight
- Vegetarians and vegans need higher end and respond better
- Older adults: particularly worth supplementing. The age-related decline in muscle creatine stores, combined with the protective effect on muscle mass and cognitive function, makes creatine one of the highest-value supplements over 50. Standard 5g daily
- Form: creatine monohydrate is the form to use. It's cheapest, most studied, and the most bioavailable. Other forms (creatine HCL, creatine ethyl ester, buffered creatine, creatine nitrate) have been marketed as "better absorbed" or "less bloating" but head-to-head comparisons consistently show no advantage over monohydrate. Pay for monohydrate, it's what the research is done on
- Micronised vs regular monohydrate: micronised is ground to a finer powder and dissolves more completely in water. Functionally identical once absorbed, but mixes better. Worth the small price difference for mixing quality
- Creapure: a branded form of monohydrate manufactured in Germany with quality certification. Not necessary, but if you want a purity guarantee, Creapure is the standard
- Absorption: creatine is absorbed well on its own. Taking it with carbs or a carb+protein meal can modestly increase muscle uptake through the insulin response, but the effect is small and not worth engineering your meals around. If you have it post-workout alongside food, that's fine. If you have it with water first thing in the morning, also fine
Here's what you can expect
If you're training regularly, you'll notice a small bump in strength and rep performance within 2-4 weeks as muscle stores fill up. Think an extra rep or two on working sets, a slightly heavier load moving cleanly, better performance on the last set of a session. The effect is not dramatic per session, it's a small per-workout advantage that compounds over months. Cumulatively, people supplementing creatine gain noticeably more strength and muscle over a training block than the same program without creatine.
You'll also gain 1-2 kg of bodyweight in the first 2-4 weeks, almost entirely intracellular water in the muscle. This is cosmetically invisible (muscles look slightly fuller, not bloated), doesn't make you look worse, and is the normal signature of successful saturation.
Side effects & risks
- Water weight gain of 1-2 kg in the first few weeks is expected and is the supplement working as intended. Intracellular, not subcutaneous, so cosmetically invisible
- GI upset (bloating, stomach discomfort, loose stools) is the most common complaint, particularly during loading or with large single doses. Resolved by splitting the dose across the day and taking with food. Skip loading if GI is an issue, just start at 5g daily
- Elevated creatinine on bloodwork. Creatine supplementation raises serum creatinine levels because creatinine is the metabolic breakdown product of phosphocreatine. This is not kidney damage, it's the normal consequence of having more creatine in your system. A comprehensive review found no evidence of kidney damage from creatine in healthy individuals. However, creatinine is used to estimate kidney function (eGFR), so creatine supplementation can cause eGFR to appear artificially low. Always flag creatine use when getting bloodwork interpreted, and ideally use cystatin C as a kidney function marker instead of creatinine if you're on creatine long-term. More detail on Bloodwork
- Kidney disease: if you have pre-existing kidney disease, talk to a doctor before supplementing. In healthy kidneys creatine is safe, in compromised kidneys the added creatinine load may be problematic
- Dehydration and cramping: these are commonly cited concerns but aren't supported by evidence. A review of 18 studies found creatine does not increase risk of dehydration, cramping, or heat illness. If anything, creatine improves hydration status by drawing water into cells. Drink water normally and there's no issue
- Hair loss: the 2009 rugby study showed a transient DHT increase during loading, and this single unreplicated finding has been used for years to claim creatine causes hair loss. Follow-up research hasn't confirmed the DHT effect and no study has ever demonstrated actual hair loss from creatine. If you're genetically predisposed to male pattern baldness, the drivers are DHT exposure over decades and hair follicle sensitivity, not creatine supplementation. The evidence doesn't support this concern
- Caffeine interaction: an older theory suggested caffeine blunts creatine's effect. Follow-up research hasn't consistently supported this. Practically, take them together if convenient
- Quality: buy monohydrate from a reputable manufacturer or a Creapure-certified product. Cheap creatine has occasionally been found contaminated with heavy metals or diluted with fillers. This is a lower concern than with some supplement categories, but still worth spending the few extra dollars on a trusted brand
Blood markers
Creatinine will be elevated during creatine supplementation, this is expected and not a sign of kidney damage. Always flag creatine use to whoever interprets your bloodwork. Typical supplementation pushes serum creatinine up by 0.1-0.3 mg/dL
eGFR (calculated from creatinine) may appear artificially low on creatine. If kidney function is a concern, request cystatin C as an alternative kidney marker, it's not affected by muscle mass or creatine intake and gives a cleaner read on actual filtration rate
BUN should be checked alongside creatinine. Normal BUN with elevated creatinine on creatine is the expected pattern and not concerning. Elevated BUN alongside elevated creatinine warrants actual kidney evaluation
Who actually needs this tested: anyone with pre-existing kidney concerns, family history of kidney disease, diabetes, or hypertension. For healthy individuals with no risk factors, baseline kidney bloodwork before starting is sensible but ongoing monitoring is unnecessary. Recheck at 3-6 months if there are concerns
Creatine is avalible in supplement shops everywhere.
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