Of all the supplements marketed to people who lift weights, creatine monohydrate has by far the largest body of research behind it, and it is one of the few where the evidence for both safety and effectiveness is genuinely strong rather than marketing-driven. For anyone training at home and wondering whether it is worth adding to a routine, the International Society of Sports Nutrition’s (ISSN) position stand is the most authoritative single summary of what is actually known.
What Creatine Does
Creatine supplementation increases the concentration of creatine and phosphocreatine stored in muscle tissue. Phosphocreatine is used to rapidly regenerate ATP, the immediate energy source for short, high-intensity efforts — the kind of effort involved in a heavy set of squats or a short sprint. With more phosphocreatine available, the ISSN position stand notes that performance of high-intensity and/or repetitive exercise is generally increased by roughly 10–20%, depending on how much intramuscular phosphocreatine rises with supplementation. In practical terms, this tends to show up as being able to complete an extra rep or two at a given weight, or recovering slightly faster between hard sets, rather than a dramatic single-session transformation.
Safety: What the Position Stand Actually Concludes
Creatine is one of the more thoroughly safety-tested supplements available. The ISSN position stand states that short and long-term supplementation, at doses up to 30 g per day for as long as five years, has been shown to be safe and well-tolerated in healthy individuals, and in a number of patient populations ranging from infants to the elderly. The position stand also directly addresses several long-running myths: it found no credible evidence linking creatine to kidney dysfunction, muscle cramping, dehydration or gastrointestinal distress in healthy users, and noted that in some studies creatine users experienced fewer injuries than non-users, not more. The one consistently reported side effect is a degree of weight gain, driven mainly by water retention in muscle tissue during the initial loading phase.
Dosing: Loading Versus Maintenance
Two dosing approaches are supported by the evidence:
- Loading protocol: approximately 0.3 g per kilogram of body weight per day, split into several doses, for 5–7 days. For a 70 kg person, that works out to roughly 20 g per day during the loading phase. This saturates muscle creatine stores faster.
- Maintenance dose: 3–5 g per day thereafter, though larger athletes may need towards the upper end, or 5–10 g per day.
- Slow-loading alternative: skipping the loading phase entirely and taking 3 g per day consistently for around 28 days produces a similar saturation of muscle creatine stores, just more gradually, with less associated water-retention weight gain in the short term.
Who the Position Stand Considers It Appropriate For
The ISSN position stand describes creatine as appropriate across a wide age range when used sensibly, including children and adolescents engaged in serious, supervised competitive training, and older adults, where creatine has also been studied in the context of preserving muscle mass and strength. It specifically characterises the common label warning against use under 18 as being driven by legal caution rather than by scientific safety data. That said, anyone under 18, pregnant, or managing an existing health condition should still involve a GP or qualified practitioner in that decision rather than treating a supplement position stand as individual medical advice.
Practical Notes for Home Training
Creatine monohydrate is the specific form with by far the largest evidence base — other forms marketed as superior (creatine ethyl ester, buffered creatine, and similar) do not have comparable research support and are typically more expensive for no demonstrated advantage. It does not need to be taken at a specific time relative to training; total daily intake and consistency matter more than timing. It is also not a substitute for progressive overload, adequate protein intake or sufficient sleep — it is a modest, well-evidenced addition on top of a training programme that is already working, not a replacement for one.
Sources
- Kreider, R.B., Kalman, D.S., Antonio, J., et al. (2017). “International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine.” Journal of the International Society of Sports Nutrition, 14:18. pmc.ncbi.nlm.nih.gov