Is creatine harmful? Side effects and who should not take it

What research says about the safety of creatine

Creatine is a substance the body produces itself from amino acids, and we also get some from meat and fish. As a food supplement, it is one of the most researched of all. In a 2017 position statement, the International Society of Sports Nutrition (ISSN) reviewed several hundred studies: short-term and long-term use of creatine monohydrate in recommended doses in healthy adults without disease showed no harmful effects. In some studies, people took it for up to five years, including amounts of up to 30 g per day.

The European Food Safety Authority (EFSA) assessed in 2004 that a daily intake of 3 g of creatine monohydrate probably does not pose a risk if the product is of suitable purity. So choose a product from a known manufacturer that clearly states the form of creatine and the amount per serving.

Side effects of creatine

Most people tolerate creatine without problems. If anything does appear, it is most often one of the following:

• More on the scale. In the first few weeks, body weight often goes up by one or two kilograms. This is mainly water that creatine holds in the muscles, not fat.
• Bloating or diarrhea. These appear mainly with large single doses, for example 10 g at once during the loading phase. The solution is smaller doses with a meal and taking it without a loading phase.
• Cramps and dehydration. These were long considered a side effect of creatine, but research has not confirmed this. A 2021 review (Antonio et al.) did not find a higher risk of cramps or dehydration, even during exercise in the heat. Still, drink enough fluids during the day.

If the problems do not go away, stop taking creatine and consult a doctor or pharmacist.

Does creatine harm the kidneys?

Not in people with healthy kidneys, according to research. A systematic review and meta-analysis from 2019 (de Souza e Silva et al.) did not show any effect of creatine on kidney function. An important detail is creatinine: this is a breakdown product of creatine, which the lab measures in blood as an indicator of kidney function. When taking creatine, it may be slightly higher without the kidneys being affected. So before blood tests, tell your doctor that you are taking creatine.

If you have kidney disease or reduced kidney function, do not take creatine without consulting a doctor.

Creatine and hair loss

The story comes from a single small study from 2009, in which 20 rugby players took creatine for three weeks. The researchers measured a higher ratio between the hormones DHT and testosterone, but they did not measure hair loss at all. The study was not repeated, and later studies found no significant changes in testosterone or DHT with creatine use. There is no evidence that creatine causes hair loss.

Who should not take creatine without consulting a doctor

• people with kidney disease or reduced kidney function,
• pregnant women and breastfeeding mothers, because there is too little safety data,
• children and teenagers,
• anyone who regularly takes medications that put strain on the kidneys (for example painkillers or diuretics), or other medicines.

For everyone else, the simple rule is: follow the recommended daily dose on the product label.

How to take creatine safely

For most adults, the usual amount is 3–5 g of creatine per day, every day. A loading phase is not necessary, and without it there is less chance of digestive problems. Take creatine with a meal or in a drink after training, and drink enough fluids during the day. You can calculate how much creatine per day, when and how to take it with the creatine calculator. Read more about creatine as an ingredient on the Creatine page, and about creatine for women in the article Creatine for women.

Kreatin Body Redefined is micronized creatine monohydrate, 5 g per serving, without flavors or sweeteners. A daily intake of 3 g of creatine increases physical performance in successive bursts of short-term, high-intensity exercise.