Taking creatine supplements at the normal dose won’t hurt your kidneys if you’re healthy — lots of studies over many years have shown no consistent sign of kidney problems.

Taking creatine powder for about a week—first a lot, then a little—can boost the amount of creatine in your muscles by over 13%, which helps your muscles store more energy.

Taking creatine monohydrate every day for up to five years, even at high doses, doesn’t seem to harm your kidneys, liver, or blood in healthy people or those with brain-related diseases like Parkinson’s or ALS.

Taking creatine supplements the way some athletes do—starting with a big dose, then switching to a smaller one—might temporarily boost the sugar stored in your muscles, but that boost fades once you switch to the smaller daily dose.

Taking 21 grams of creatine a day for 5 days can boost the amount of creatine in your muscles by about 30%, but it doesn’t make your muscles build protein faster or break it down slower, whether you’ve eaten or not.

Taking creatine supplements for about six weeks doesn’t seem to change the levels of a specific protein and its genetic instructions in your muscles, even if you’re healthy.