Repeatedly tested in people, with results that agree.
Yes, if you lift — and only if you lift. It is the most-tested supplement in sports nutrition and one of fifteen practices in our library rated A. Without resistance training there is little to show for it.
Most supplement questions have a disappointing answer. This one does not, which is worth saying plainly on a site that spends most of its time downgrading things.
What the evidence actually is
Hundreds of trials, and a position stand from the International Society of Sports Nutrition (Kreider et al., 2017). The finding: a little more strength and lean mass from resistance training once muscle creatine stores are full, and no harm to kidney function in healthy adults across years of use. That combination — a real effect, repeatedly replicated, with long-run safety data — is what an A means in our library. Fifteen of 204 practices have one.
What it will not do
- Work without training. The effect is on what resistance training produces, not on the body at rest. If you are not lifting, this is a purchase with nothing attached to it.
- Work faster in an expensive form. Plain monohydrate is the form the evidence used. The variants that cost more have not beaten it.
- Reward a loading week. The position stand describes three to five grams a day filling the stores over three to four weeks. A larger loading phase gets there faster; it does not get you further.
The water-weight thing
A kilo or so in the first weeks is normal, it is water, and it is not fat. It is also the single most common reason people stop in the first month, which is why it is on the practice card in the app rather than in a footnote.
Why an A here and a D on magnesium
Because that is what the two literatures look like. A library where everything scored well would be telling you nothing, and one where nothing did would be posturing. Magnesium for sleep is rated D on the same scale by the same method: systematic reviews rate its evidence low to very low. The grades are only useful if they move. All 204 are published, including the 122 rated C or weaker.
Before you try it
An existing kidney condition changes the picture entirely — that is a doctor’s call, not this card’s. A kilo or so of water in the first weeks is normal and is not fat. Education, never advice: nothing here tells you to take anything, and no amount on this card outranks a label or a professional. Talk to a doctor or pharmacist before starting anything — especially if you take any medication, because interactions are real; if you are pregnant or breastfeeding; if you have a kidney or liver condition; or if you have any history of disordered eating.
IntentNorth is an iPhone app that puts practices like this one into your actual week — at real times, around what you already have on, with the grade on each one. It changes the week when your week changes.
How this is graded. Every practice in IntentNorth carries a letter from A to E for the strength of the research behind it, shown on the practice itself rather than in a footnote. All 204 are published, and 122 of them are rated C or weaker. Read the whole library.
Educational information, not medical advice. Nothing here is a diagnosis or a personal recommendation, and none of it replaces a conversation with your doctor or pharmacist.
Last reviewed September 2026