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Creatine side effects and how to avoid them

Creatine side effects are rare but some users have reported mild symptoms like stomach discomfort and muscle cramps, which may or may not be related to the supplement
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By | Dec. 29, 2023 Medically reviewed by Josephine Bawab, Pharm.D.
A spilled bottle of capsules: Creatine side effects

Key takeaways

  • Creatine side effects are rare, with weight gain from increased muscle mass or fluid retention being the only significant side effect supported by clinical studies.

  • Anecdotal reports link creatine usage to various minor side effects such as muscle cramps and stomach upset, but these are not consistently backed by scientific research.

  • There is no evidence of serious health risks associated with creatine supplementation, including no proven impact on kidney function or long-term negative effects when taken as recommended.

  • To minimize potential side effects, individuals should consult healthcare professionals before use, avoid excessive doses, and maintain proper hydration and exercise practices.

In this article:

Creatine is a naturally occurring amino acid that is vital to producing short-burst muscle energy. It’s also vital to brain function, muscle repair, muscle hydration, and the body’s production of hormones, such as estrogen, testosterone, and insulin. Most people get all of the creatine that they need from eating red meat and fish, in addition to the creatine naturally produced in the body. Even so, creatine dietary supplements are popular among strength athletes, professional athletes, and bodybuilders to improve athletic performance, muscle growth, and overall strength. 

Some healthcare providers recommend or prescribe creatine supplements to vegetarians who don’t get enough naturally occurring creatine in their diet and people with creatine deficiency disorders or diseases that reduce lean muscle mass. Creatine supplements may also improve blood sugar levels in people with diabetes, improve cognitive functioning, and slow down age-related muscle and bone loss. 

Common side effects of creatine

Clinical studies have found no significant side effects from creatine supplementation when recommended dosages are followed, and the International Society of Sports Nutrition supports its use. The only potential side effect consistently reported in clinical studies is weight gain, but researchers believe this weight gain is largely due to increased lean muscle mass or increased fluid concentrations in muscle tissues.

However, there are anecdotal reports of creatine side effects. Although most have been disproven in clinical studies, the most common creatine side effects reported outside of clinical studies include:

  • Muscle injuries
  • Muscle cramps
  • Dehydration
  • Stomach upset
  • Bloating
  • Hair loss
  • Headache
  • Irritability
  • Aggression
  • Edema
  • Electrolyte imbalance
  • Weight gain

Some reported side effects may be related to high-intensity exercise or the use of other performance-enhancing substances, such as anabolic steroids. 

Serious side effects of creatine

Clinical studies have found no evidence of serious side effects of creatine supplementation, even when creatine supplements are taken in excess. 

Does creatine make you gain weight?

The only demonstrated side effect of creatine is weight gain. Healthcare professionals believe this increase in body weight is largely due to an increase in skeletal muscle mass or water retention in the muscle cells rather than fat deposition. Neither of these is unhealthy. 

Does creatine cause hair loss?

Hair loss is a reported side effect of creatine use, but the International Society of Sports Nutrition has not found evidence of hair loss caused by creatine supplementation. Hair loss may be associated with creatine because the supplement is popular among bodybuilders and strength athletes who may also be using testosterone. A prominent side effect of testosterone use is hair loss.

Does creatine cause acne?

There is no scientific evidence that creatine supplementation causes acne. However, acne may be a side effect of other substances people are taking, such as anabolic steroid injections.

How soon do creatine side effects start?

Except for weight gain, side effects attributed to creatine are based on case reports rather than clinical studies. Because of this, there’s no information about when the side effects of creatine start. However, there may be side effects due to other substances or impurities in the supplement, such as gastrointestinal problems or allergic reactions. These reactions may start shortly after the supplement is taken.

What are the long-term side effects of creatine?

There are no long-term side effects associated with creatine supplements. Based on clinical and anecdotal evidence, no negative side effects are associated with chronic supplementation of creatine. 

Creatine interactions that increase the risk of side effects

There are no proven creatine drug interactions. However, some healthcare professionals worry that creatine can hurt the kidneys, so they warn users to avoid drugs that are known to harm the kidneys, such as nonsteroidal anti-inflammatory drugs (NSAIDs), diuretics (water pills), cimetidine (a stomach acid reducer), and other drugs that can be toxic to the kidneys. Additionally, caffeine may reduce the energy and exercise benefits of creatine supplements.

Safety measures while using creatine

Although no clinical study has shown that creatine causes kidney damage, at least one case study indicates that normal doses may cause kidney injury. For this reason, healthcare providers caution anyone with reduced kidney function or taking drugs that can harm the kidneys to seek medical advice before taking creatine.

Some healthcare professionals may warn people with liver dysfunction or high blood pressure to avoid creatine supplementation. 

Children

No studies have determined whether or not creatine is safe for children or adolescents to take. Creatine supplements are commonly used in children for certain disorders, but healthcare professionals generally advise that teen and child athletes should not take creatine to improve athletic performance. 

Pregnancy

Pregnant women or women planning to become pregnant should talk to a healthcare professional about the safety of taking creatine before starting it. There is no evidence that creatine causes pregnancy problems or birth defects. Some studies suggest that creatine supplementation may help with problem pregnancies. 

Breastfeeding

Nursing mothers should get medical advice from a healthcare professional before taking creatine supplements. Creatine is naturally present in human breast milk. It hasn’t yet been determined whether taking creatine supplements increases the amount of creatinine in breast milk. It’s also uncertain whether creatine supplements affect lactation or if higher levels of creatine in breast milk affect a nursing baby. 

Dependence

Creatine supplements do not create physical dependence. Some healthcare professionals worry that creatine supplementation may decrease the body’s ability to make or store creatine. However, declining creatine stores in the body seem to be only a temporary problem after discontinuing the supplement. 

Withdrawal

Stopping creatine supplements will not cause withdrawal symptoms. However, creatine levels in the body may fall after discontinuing creatine supplements. As a result, people may not be able to exercise at the same intensity level or may get tired more easily. 

Overdose

If too much of any supplement is taken, call 911 or get immediate medical help. A creatine overdose may or may not cause problems. If too much creatine is ingested, the body eliminates the excess amount since it stores creatine in the muscles, where there’s limited storage space. 

How to avoid creatine side effects

People only rarely experience side effects, and there are not enough instances of side effects occurring to be significant in clinical studies. However, just because creatine side effects are only known from anecdotes and case studies, it doesn’t mean that they aren’t possible. Some people may have unique, idiosyncratic responses to a supplement, especially in high doses. However, there are ways to minimize the risk of possible side effects:

1.  Get medical advice before taking creatine supplements.

Talk to a doctor or other healthcare professional before taking creatine or other performance-enhancing substances. This is important for everyone, but it’s especially important for people with kidney or liver problems and pregnant or nursing mothers. 

2.  Don’t take too much.

If you’re worried about creatine side effects, don’t overdo it. Although athletes are advised to take high doses of creatine during a “loading phase” for several days, there’s no proof that high-loading doses are necessary, so it may be best to avoid them. Older adults taking creatine to preserve cognitive function, bone density, or muscle mass won’t need to take high doses of creatine. 

3.  Don’t overexert yourself.

Creatine supplements are believed to increase a person’s ability to exercise at a higher intensity. That doesn’t mean you should exercise more intensely. Many of creatine’s reported, but unproven, side effects—muscle cramps, muscle damage, rhabdomyolysis (with kidney damage), dehydration, and stomach pain—are similar to problems caused by high-intensity physical activity. If you experience these problems, they may be a sign that you’re working out too hard.

4.  Follow best practices when exercising or playing sports.

Some of the side effects that have been reported in people taking creatine supplements are common problems associated with physical activity or sports. Staying hydrated, stretching, avoiding overexertion, and resting may be the most effective ways to avoid some of the problems associated with creatine supplements.

5.  Be wary when using creatine with other performance-enhancing supplements or drugs.

Many side effects that are reported to have occurred with creatine supplements are known side effects of other supplements and performance-enhancing substances. Some of these, like anabolic steroids, are unsafe. If you’re concerned about creatine side effects, you should look into the potential side effects of other substances that you may be taking.

6.  Be careful about taking drugs that damage the kidneys.

Research indicates that creatine does not damage the kidneys, but some healthcare providers question this. No matter what the reason for taking creatine is, avoid using it with drugs known to damage the kidneys just to be safe.  

7.  Do your research.

The riskiest aspect of most nutritional supplements is product quality. The supplement industry isn’t federally regulated. Read the product label to scan for ingredients that may cause problems, such as allergic reactions or stomach pain. Beware that poor-quality products may contain contaminants or impurities that can cause serious problems, so it is important to research the manufacturer’s quality record and recall record. One way to do this is to check for a label indicating that it has been tested by the U.S. Pharmacopoeial (USP) Convention Dietary Supplement Verification Program. If it’s USP-verified, it ensures that it contains the ingredients listed and isn’t contaminated. You could also ask a healthcare professional for advice.

How to treat side effects of creatine

No study has shown that creatine causes clinically significant side effects. However, there are case reports of muscle damage, kidney damage, and other problems. If any adverse effects are experienced when taking creatine, immediately stop taking all supplements and performance-enhancing substances. You might consider taking a rest from physical activity. Talk to a healthcare professional before resuming the supplement. 

Bottom line: Is creatine safe?

Healthcare professionals and the Food and Drug Administration (FDA) consider the use of creatine to be safe when taken at the recommended dosage by healthy individuals. There are no proven negative side effects or drug interactions other than weight gain. There are no known reports of anyone becoming seriously ill from taking too much creatine, although some people may experience kidney dysfunction. Pregnant women, nursing women, and people with kidney disorders, liver problems, or high blood pressure should first talk to a healthcare professional before taking creatine supplements.