Does creatine work, and is it safe?

Creatine monohydrate is one of the most researched supplements. The International Society of Sports Nutrition calls it the most effective supplement for increasing high-intensity exercise capacity and muscle mass during training. A typical dose is 3 to 5 grams a day, and the research finds it safe for healthy adults. If you have kidney disease or another condition, ask your doctor first.

1. Pick creatine monohydrate. It's the form with the most research behind it, and usually the cheapest.
2. Take 3 to 5 grams a day. Any time of day works. Taking it daily matters more than timing.
3. Load if you want faster results. Optional. About 20 grams a day split into four doses for 5 to 7 days fills your muscles faster, then drop to 3 to 5 grams.
4. Give it a few weeks. Without loading, it takes about 3 to 4 weeks for your muscles to fill up.

What creatine does

Your muscles use creatine to make quick energy for short, hard efforts like a heavy set or a sprint. Supplementing raises the amount stored in your muscles, which helps you do a little more work in training. Over weeks, that extra work adds up to more strength and muscle.

What the position stand says

The International Society of Sports Nutrition reviewed the research in 2017. Its main points:

• Creatine monohydrate is the most effective supplement available for increasing high-intensity exercise capacity and lean body mass during training.
• Short-term and long-term use appears safe and well tolerated in healthy people.
• A daily dose of 3 to 5 grams keeps muscle stores full after loading, or fills them over a few weeks without it.
• Creatine monohydrate is the form with the most evidence behind it.

Who should be careful

If you have kidney disease, take medicines that affect your kidneys, or are pregnant, talk to your doctor before taking creatine. Buy from brands that use third-party testing, since supplements aren’t checked by regulators before they’re sold.