Is Creatine Safe for Your Kidneys?

November 24, 2019

by Cathe Friedrich

Creatine is one of the more popular supplements that bodybuilders and active people use. It has several benefits that make it attractive for people who lift weights or play sports. The main reason people use it is hoping to lift heavier, improving exercise performance, or building more muscle. There is evidence that creatine can help with these goals. However, you should always consider safety when taking a supplement. Occasionally, people who take creatine develop a rise in creatinine in their bloodstream. High creatinine in the blood is a marker of worsening kidney function. Is creatine harmful to the kidneys?

Fitness Benefits of Creatine

First, let’s look at the fitness benefits of creatine. Taking creatine boosts the amount of phosphocreatine inside muscle cells. That’s important since muscle cells can use phosphocreatine for energy. You use phosphocreatine as a short-term energy source when lifting weights or doing short-term, high-intensity exercise. It also helps recycle ATP, a cell’s energy currency. Therefore, it has performance benefits, mainly for short-term, high-intensity exercise. There’s no evidence that it enhances performance for endurance exercise. Studies also show that it increases growth factors, such as IGF-1, within muscle cells. This may boost muscle hypertrophy.

Beyond the performance benefits, creatine may also make your muscles look “beefier.” When you have more creatine phosphate inside your muscle cells, the muscle retains more water and look larger. Serious bodybuilders like the way their muscles look when they take creatine, although it’s mostly due to swelling and the swelling will reverse if they stop taking it. It’s not because of an increase in muscle fiber size, although some evidence suggests that creatinine can improve strength-training performance. Some research also suggests that creatine supplements help muscles recover faster after a workout.

How it makes your muscles look and perform is one thing, but the most important issue to consider before popping a creatine supplement is safety. One question some people raise is how safe is creatine for the kidneys?

Creatine, Creatinine, and Your Kidneys

People often confuse creatine and creatinine but they are different. Health care professionals use creatinine as a marker of kidney function. In fact, one way they screen for kidney failure is to measure how much creatinine is in the bloodstream. Creatinine levels above normal suggest that the kidneys aren’t working as well as they should. A rise in creatinine can be the first sign of kidney failure.

Despite being different molecules, creatine and creatinine are related. When you take in creatine in the form of a supplement or from natural sources like meat, certain tissues, including your muscles, convert it to phosphocreatine. When your muscles need energy, cells can use the phosphate group to make ATP, the energy that drives muscle contractions. What’s left over is creatinine and your kidneys have ways of handling that. In a healthy person, only a certain amount of creatinine stays in the blood You can measure how much through a blood test and it’s one of the most useful markers of kidney function.‘

Therefore, if you have a creatinine level out of range on a blood test, it raises red flags about the health of your kidneys. But if you’re flooding your body with creatine by taking a supplement, wouldn’t you expect the amount in your blood to go up? That’s exactly what studies show. If you’re taking a moderate dose of creatine, it may raise your creatinine level. However, the rise isn’t associated with worsening kidney function. But don’t overboard. Some research suggests that taking over 10 grams of creatine daily could be unsafe longer term.

How much does creatine do you have to take to see a rise in creatinine? Most research shows you won’t see a significant bump up in creatinine if you take less than 5 grams of creatine daily but taking more can cause a small rise in blood creatinine. However, this rise in creatinine isn’t linked with abnormal kidney function.

Is Creatine Safe to Use Long-Term Use

Although the rise in creatinine in people who take a high dose of creatinine doesn’t indicate kidney problems, it’s not clear whether taking creatine long-term is safe for people who already have kidney disease. At least short-term, it doesn’t seem to worsen kidney function, but few studies have looked at how creatine affects kidney function over a long period in those who already have kidney disease. It’s reassuring that short-term studies in people with kidney disease and type 2 diabetes show no harm, but it’s safest to get a doctor’s okay before taking it if you have a history of kidney disease or abnormal kidney function.

Can You Get Enough Creatine from Food Sources?

The dosage of creatine athletes take varies from 3 grams up to 10 grams daily. Ten grams is at the high end of what research finds is safe and would only be appropriate for larger people who exercise intensely. You can get creatine from natural sources like meat and fish, but you’d have to eat a lot. One pound of beef or salmon only supplies 1 to 3 grams of creatine. For most people, especially those who eat a vegetarian diet, it’s not practical to get that amount through diet alone.

Should You Take Creatine?

Creatine is safe for a healthy person short-term, but there are still questions about whether people who have certain health conditions should take it longer term. Plus, most of the studies looking at its benefits are in men. Some research suggests that the benefits may be less impressive in women. Whether you take it should depend on your goals. If you compete in sports where you exercise at a high intensity or if you are a natural ectomorph who wants more lean body mass, supplementing with creatine may be helpful. If you’re a vegetarian or vegan, supplementing with creatine makes sense too since you’re not getting a lot from dietary sources. Plants are not a good source of creatine. However, studies suggest that people have varying responses to creatine. Some people get little or no benefit. Also, keep in mind that we don’t know if it’s safe to use over a very long period.

References:

Acta Physiol Scand. 1995 Jul;154(3):303-10.
Int J Sport Nutr Exerc Metab. 2008 Aug;18(4):389-98.
Am J Kidney Dis. 2010 Mar;55(3):e7-9. doi: 10.1053/j.ajkd.2009.10.053. Epub 2010 Jan 8.
Eur J Appl Physiol. 2011 May;111(5):749-56. doi: 10.1007/s00421-010-1676-3. Epub 2010 Oct 26.
Perm J. 2012 Spring;16(2):51-2.
Journal of the International Society of Sports Nutrition volume 14, Article number: 18 (2017)
com. “An Overview of Creatine Supplements”