Creatine Side Effects: What's Real, What's a Myth

By Roy Anderson, Founder of GUMO · Reviewed by Koji Wang, Physiotherapist · Last updated 23 October 2026

The most common side effects of creatine are a small amount of water weight and, at high doses, an upset stomach. Both are mild and easy to avoid. The scarier claims you'll see online, like kidney damage, dehydration, cramps and hair loss, aren't supported by the research in healthy people.

You don't have to take my word for it as someone who sells creatine. The Australian Institute of Sport puts it plainly: "There is no evidence of systematic serious adverse effects related to creatine monohydrate supplementation." Below is what's real, what's a myth, and who should check with a doctor first.

What are the side effects of creatine?

Creatine monohydrate side effects are a short list. The rumoured ones are a much longer list. Here's how they stack up against the evidence.

Water retention and weight gain

This is the side effect almost everyone notices. Creatine draws water into your muscle cells, so the scales usually go up a little in the first few weeks. It's water inside the muscle, not fat, and it's actually part of how creatine works.

According to the AIS, the gain is a maximum of about 1 or 2kg, and it stays while your muscle creatine stays topped up. If you stop, it drops back to normal over 4 to 6 weeks. The only people who really need to think about it are athletes in weight-class sports trying to make weight.

It's more noticeable if you load. When I did a loading phase, the main thing I noticed was how much more water I was drinking and how often I was running to the toilet. Taking 3 to 5g a day instead lets it happen gradually, and most people barely notice. More in does creatine make you gain weight?

Stomach upset, bloating and diarrhoea

Gut issues are the second most common side effect, and they're strongly linked to dose. A 2008 study in athletes found that taking 10g in a single dose caused diarrhoea far more often than the same amount split into two 5g doses, which was no different from a placebo.

The AIS describes gut upset as mild and temporary, and suggests a few simple ways to avoid it: skip the loading phase, take creatine with meals, and don't take it at the same time as high fibre foods or supplements known to upset the stomach, like sodium bicarbonate.

If creatine does bother your stomach, halve your dose for a week or two and build back up. And if you take creatine gummies, check the sweetener, which I'll come to below.

Does creatine damage your kidneys?

Not in healthy people. This is the biggest worry people have, and it's been studied a lot. A 2019 systematic review published by the National Kidney Foundation reviewed 15 studies and concluded creatine "does not induce renal damage in the studied amounts and durations". An earlier review in Sports Medicine monitored athletes' kidney function for up to five years of creatine use and found no adverse effects.

So where does the worry come from? Creatine breaks down into creatinine, and creatinine is what doctors measure in a standard kidney blood test. Taking creatine can nudge your creatinine up, which can look like a kidney problem on paper when your kidneys are fine. Tell your doctor you take creatine before any blood test.

The exception is people who already have kidney disease. There isn't enough research to say creatine is safe for them, so talk to your doctor first.

Does creatine cause dehydration or cramps?

No. This one's been around since the 1990s, but the research doesn't back it up. A 2009 systematic review found that creatine doesn't hinder heat tolerance or hydration status, and studies in athletes have found creatine users actually reported fewer cramps and muscle injuries than non-users. The AIS says claims about creatine causing muscle, kidney or overheating problems "are not supported with research".

Does creatine cause hair loss?

There's no good evidence that it does. The idea traces back to one small 2009 study in rugby players, which found a rise in DHT, a hormone linked to hair loss. It didn't measure hair loss, and it's never been replicated. A 2021 review of creatine myths concluded the evidence doesn't show creatine increasing testosterone or DHT, or causing hair loss. For what it's worth, my dad was bald by about 40, and three-plus years of daily creatine hasn't done anything to my hair. More in does creatine cause hair loss?

Other creatine myths

A few other side effects come up often online. None of them hold up well.

The liver gets mentioned because it helps make and process creatine, but studies in healthy people haven't found liver problems. The 2000 Sports Medicine review checked liver markers in athletes over four weeks of creatine use and found no sign of dysfunction. If you drink, our guide to creatine and alcohol covers the liver research in more detail.

Acne is another one. No research links creatine to breakouts. If you're training harder and sweating more, that's a far more likely culprit.

Then there's rhabdomyolysis, a serious condition where muscle tissue breaks down. The myth seems to have started because a similarly named marker, creatine kinase, is used to diagnose it. There's no evidence that creatine supplements cause it.

And no, creatine isn't a steroid. It isn't a hormone at all; it's a compound your body makes every day from amino acids. More in is creatine a steroid?

Creatine side effects in women

Women get the same side effects as men, and the same myths apply. The two questions women ask most are about weight gain and hormones.

On weight, any early gain is water in the muscles, not fat, and a 2021 review of creatine in women found it caused no more side effects than a placebo. On hormones, the small studies that measured oestrogen haven't found creatine changing it. The one group that should hold off is pregnant or breastfeeding women, because there isn't enough safety data yet. For the full picture, see creatine for women.

Side effects of creatine gummies

Gummies have the same creatine side effects as powder, plus a couple that come from what else is in them (if you're still choosing a format, see powder vs capsules vs gummies). They're worth knowing about if you're choosing a gummy.

Sugar is the obvious one. Some gummies use glucose syrup and sugar, which adds up if you take them every day. Sugar-free gummies often use sugar alcohols instead. Maltitol and sorbitol are the ones most likely to cause bloating, wind and loose stools in larger amounts. If a gummy upsets your stomach, check the ingredient list before blaming the creatine.

For transparency, our creatine gummies contain no sugar. They're sweetened with maltitol syrup, along with small amounts of stevia and sucralose, and a four-gummy serve contains 8.6g of carbohydrate in total. That's a long way below the amount that caused problems in a 2003 tolerance study, where 12 healthy adults needed an average of about 92g of maltitol in a day before they got diarrhoea or severe symptoms. Everyone's gut is different, though, so if sugar-free lollies tend to upset you, take your serve with food.

The bigger issue is quality. Lab tests have found many creatine gummies are underdosed, and poorly made creatine can contain extra creatinine and other by-products. A 2011 study of 33 creatine supplements found creatinine was the main contaminant, above 100 mg/kg in 44% of samples. Choose a brand that publishes independent batch testing.

A note on bias: GUMO makes creatine gummies, so we have an interest here. That's why every claim in this guide links to its source, and why we're telling you to check any gummy's label, including ours.

Who should avoid creatine?

Creatine is safe for most healthy adults. Mayo Clinic rates it generally safe at recommended doses for up to five years. But you should talk to your GP before taking it if you:

• have kidney disease or liver disease
• are pregnant or breastfeeding
• are under 18
• have diabetes, or take medication that affects your blood sugar or kidneys
• have bipolar disorder, since Cleveland Clinic notes creatine may increase the risk of mania

Mayo Clinic also flags caffeine as a possible interaction: large amounts might reduce how well creatine works, though the research isn't settled.

What happens when you stop taking creatine?

Nothing dramatic. There's no withdrawal. Your body keeps making its own creatine, and your muscle stores drift back to their normal level over about a month. The water weight goes with them, so you might see the scales drop by a kilo or so over 4 to 6 weeks.

You won't lose muscle you built while taking it, as long as you keep training. You'll just lose the small extra boost in training capacity, which is why you might feel slightly flatter in hard sessions.

How to avoid creatine side effects

Most creatine side effects come down to dose and how you take it. These habits prevent nearly all of them:

1. Take 3 to 5g a day and skip the loading phase unless you have a good reason to load.
2. Never take 10g or more in one go. If you take more than 5g, split it up.
3. Take it with a meal, and not at the same time as high fibre foods or sodium bicarbonate.
4. Drink water normally through the day. You don't need extra, but don't skimp either.
5. Choose creatine monohydrate from a brand with independent batch testing.

For dosing by body weight, see how much creatine per day.

Frequently asked questions

Is creatine good for you?

For most healthy adults, yes. Creatine is one of the most researched supplements available, it helps with strength and training performance, and the AIS lists it among the supplements with the strongest evidence. Its main downsides are mild water weight and possible stomach upset at high doses.

Is creatine safe?

Creatine is safe for healthy adults at 3 to 5g a day. Mayo Clinic rates it generally safe for up to five years of use, and reviews of kidney and liver function haven't found harm in healthy people. People with kidney disease, pregnant or breastfeeding women and under 18s should check with a doctor first.

Is creatine bad for you?

Not at recommended doses, if you're healthy. The worst most people experience is a little water weight or an upset stomach from taking too much at once. The bigger risks are low quality products, so choose a brand with independent testing.

What is the biggest side effect of creatine?

Water weight is the most common side effect: a gain of up to about 1 to 2kg from water stored in your muscles. Stomach upset is the second most common, and it's mostly caused by large single doses.

Is it OK to take creatine every day?

Yes. Creatine is designed to be taken daily, and studies of up to five years in healthy people haven't found harmful effects. Daily use keeps your muscle stores topped up, which is how it works.

Why do some doctors say not to take creatine?

Usually because creatine raises creatinine on blood tests, which can look like a kidney problem, or because the person has a condition like kidney disease. For healthy adults, Mayo Clinic rates creatine generally safe. Always tell your doctor you take it.

Does creatine affect sleep?

There's no good evidence that creatine disrupts sleep. Some early research suggests it may even help with tiredness after a poor night's sleep, but more studies are needed. Since timing doesn't matter much, take it earlier in the day if you're unsure.

Can creatine cause headaches?

There's no good research showing creatine causes headaches, though some people report them. If you get one, check you're drinking normally through the day and not taking a large single dose, and see your GP if they keep happening.

Can creatine cause heart problems?

There's no evidence that creatine causes heart problems in healthy people. If you have a heart condition or high blood pressure, check with your doctor before taking any supplement, including creatine.

Will I look leaner when I stop taking creatine?

You may look very slightly less full as the extra water leaves your muscles, and the scales may drop a little. You won't lose fat by stopping, and you'll keep the muscle you built as long as you keep training.

Sources

• Australian Institute of Sport: Creatine, are there any concerns or considerations?
• Poortmans J.R. & Francaux M. (2000). Adverse effects of creatine supplementation: fact or fiction? Sports Medicine, 30(3), 155 to 170
• de Souza e Silva A. et al. (2019). Effects of creatine supplementation on renal function: a systematic review and meta-analysis. Journal of Renal Nutrition, 29(6), 480 to 489
• Lopez R.M. et al. (2009). Does creatine supplementation hinder exercise heat tolerance or hydration status? A systematic review with meta-analyses. Journal of Athletic Training, 44(2), 215 to 223
• Antonio J. et al. (2021). Common questions and misconceptions about creatine supplementation. Journal of the International Society of Sports Nutrition, 18(1), 13
• Kreider R.B. et al. (2017). International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation
• Ostojic S.M. & Ahmetovic Z. (2008). Gastrointestinal distress after creatine supplementation in athletes: are side effects dose dependent? Research in Sports Medicine
• Ruskoné-Fourmestraux A. et al. (2003). A digestive tolerance study of maltitol after occasional and regular consumption in healthy humans. European Journal of Clinical Nutrition, 57(1), 26 to 30
• Mayo Clinic: Creatine (updated April 2026)
• Cleveland Clinic: Creatine
• Moreta S. et al. (2011). Levels of creatine, organic contaminants and heavy metals in creatine dietary supplements. Food Chemistry, 126(3), 1232 to 1238

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About the author
Roy Anderson is the founder of GUMO and has taken creatine daily for over three years. He started GUMO after seeing brand after brand sell creatine gummies with little or no creatine inside. Every batch of GUMO Creatine Gummies is third party lab tested in Australia, with the results published. Read more about Roy →