The Complete Guide to Creatine Supplementation

Creatine monohydrate is, by volume of research, the most extensively studied sports supplement available — and also one of the most misunderstood outside of exercise science circles. This guide brings together what the evidence actually supports, in one place, with links to focused answers on the specific questions people ask most.

How creatine works

Creatine is stored primarily in skeletal muscle as phosphocreatine, which the body uses to rapidly regenerate ATP — the energy currency muscles use during short, high-intensity efforts (think: a heavy set of squats, a sprint, a vertical jump). Supplementing increases the muscle’s phosphocreatine stores beyond what diet alone typically provides, which is why it has a measurable, if modest, effect on strength and power output in trained individuals.

Dosing approaches

Two common protocols show up in the literature:

1. Loading phase: ~20g/day (split into 4 doses) for 5–7 days, followed by a 3–5g/day maintenance dose. This saturates muscle stores faster.
2. Maintenance-only: 3–5g/day from the start, reaching full saturation over roughly 3–4 weeks without a loading phase.

Both approaches reach the same steady-state muscle saturation; the loading phase just gets there faster. Neither is “more correct” — it’s a tradeoff between patience and gut comfort (loading doses are more likely to cause mild GI discomfort in some people).

Hydration

See our focused answer: How much water should you drink daily when taking creatine? — the short version is that normal adult fluid guidance, plus a bit more on training days, is sufficient; there’s no creatine-specific hydration formula validated by research.

Kidney safety

This is the most persistent safety question, and it has a clear answer for the general healthy population: see Does creatine cause kidney damage in healthy adults? for the full sourced explanation, including why creatine raises the standard creatinine lab marker without indicating actual kidney harm.

Special populations and medication interactions

If you’re taking other medications, especially ones that affect kidney function or fluid balance, individualized guidance matters more than general population data. Our answer on creatine and GLP-1 medications is a good example of how to think through a specific interaction question: look for a plausible mechanism, check what’s actually been studied, and identify what’s genuinely unknown versus reassuringly established.

Who should talk to a doctor first

• Anyone with existing kidney disease or a single kidney
• Anyone on medications that affect kidney function
• Anyone pregnant or breastfeeding (limited safety data in this population)
• Anyone under 18 (limited long-term data; consult a pediatrician)

Bottom line

Creatine monohydrate, at standard doses, has one of the strongest safety and efficacy track records of any widely used supplement. The open questions that remain are mostly about specific populations and edge cases — which is exactly what our focused question pages in this cluster are designed to address individually.