The short version
Take 3–5 grams of creatine monohydrate every day. That's about 0.03 g per kilogram of body weight, and it fills your muscle creatine stores in three to four weeks. If you want to get there in a week, do a loading phase first: about 0.3 g/kg per day (roughly 20 g) split into four doses for 5–7 days, then drop back to 3–5 g. Timing barely matters; consistency matters completely. Expect a couple of pounds of water inside the muscle in the first weeks. Stay hydrated the way you should anyway, plus a glass with each dose.
Where the numbers come from
| Rule | Number | Source |
| Maintenance dose | 3–5 g/day (~0.03 g/kg) | ISSN position stand, 2017 |
| Loading dose | ~0.3 g/kg/day × 5–7 days, 4 doses | ISSN position stand; Hultman 1996 |
| No-load saturation | 3 g/day × 28 days = 20 g/day × 6 days | Hultman et al., J Appl Physiol 1996 |
| Older adults 60+ | ~0.1 g/kg/day with resistance training | Candow et al. |
| Women's stores | 70–80% lower than men's | Smith-Ryan et al., Nutrients 2021 |
| Water | 3.7 L men / 2.7 L women total, ~80% from drinks | National Academies DRI |
| Safety | No harm at up to 30 g/day for 5 years in healthy adults | ISSN position stand |
Who should check with a doctor first
Creatine has an excellent safety record in healthy adults. If you have kidney disease, are pregnant or breastfeeding, take medications that affect the kidneys, or are under 18, talk to your doctor before starting. And whatever your situation, tell your doctor you take creatine before blood work — it raises creatinine, which can look like a kidney problem if they don't know.
What these calculators do — and don't do
They apply the published rules to your body weight and situation and convert the answer into real units you can measure. They are educational estimates, not medical advice, and they assume creatine monohydrate — the form every major study used. They don't diagnose, don't account for medical conditions, and don't replace the label on the product in your hand.