What creatine actually does, by mechanism

What people ask us next.

Q01

What does creatine actually do in the body?

It refills your fast energy system. Creatine is stored in muscle as phosphocreatine, which regenerates ATP, the cell's energy currency, during short maximal efforts under ~10 seconds. Supplementing raises muscle phosphocreatine ~20% (Harris 1992), so you can do 1-2 more hard reps or sprints before fatiguing. Over a training block that extra volume drives ~5-15% greater strength and ~1-2 kg more lean mass (Kreider 2017).

Q02

How long does creatine take to work?

Muscle stores saturate in ~3-4 weeks at 3-5 g/day, or ~1 week if you load with 20 g/day for 5-7 days first (Hultman 1996). The performance benefit appears once stores are saturated, not on day one; creatine is not a pre-workout stimulant and you feel nothing acutely. Final saturation is identical whether you load or not, so loading only buys speed.

Q03

Does creatine build muscle directly?

No, indirectly. Creatine does not signal muscle growth itself; it lets you perform more total training volume (extra reps and sprints), and that added volume is what builds muscle over weeks. Rawson & Volek 2003 found creatine plus lifting produced ~8% more strength than lifting plus placebo. Part of the early 1-2 kg gain is also intracellular water (Francaux 2003), which is muscle-bound, not fat.

Q04

Does creatine help the brain?

There is emerging evidence, strongest under stress. The brain uses phosphocreatine for energy, and Avgerinos et al. 2018 found creatine improved short-term memory and reasoning, with the largest effects in older adults and during sleep deprivation. In well-rested young people the cognitive effect is smaller and less consistent. It is a legitimate secondary benefit, not the primary reason most people supplement.

Q05

What is the right dose of creatine?

3-5 g/day of creatine monohydrate, taken every day. Scale to ~0.03 g/kg for body size. Loading (20 g/day for 5-7 days) only speeds up saturation by a couple of weeks and is optional; it also causes more GI upset. No cycling is needed, timing around workouts barely matters, and plain monohydrate beats the pricier HCl or buffered forms on cost with no loss of effect.

Q06

Does everyone respond to creatine?

Most people do, but roughly 20-30% are 'non-responders' whose muscle creatine is already near-saturated from diet, typically high meat-eaters (Syrotuik & Bell 2004). Vegetarians and vegans tend to respond most strongly because their baseline stores are lower. If you see no strength change after 4-6 weeks of consistent 5 g/day with progressive training, you may be a non-responder; the supplement is still safe, it just has less room to help you.