Creatine GuidesOct 22, 2026

Does Creatine Break a Fast? It Depends on Your Fast (and Your Creatine)

Plain creatine won't break most fasts, but gummies and flavoured powders can. Here's how to check yours.

Woman drinking water at a kitchen bench while fasting, creatine gummies set aside

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

Plain creatine monohydrate mixed with water almost certainly doesn't break a fast. It has no sugar, fat or protein, and in a classic 1996 study, 5g of creatine on its own had no effect on insulin. Gummies and flavoured powders are a different story: most contain carbohydrate or sweeteners, so whether yours breaks a fast depends on what's on the label and what kind of fast you're doing.

That last bit matters more than most articles admit. A 16:8 fast for weight loss, a fast for autophagy, Ramadan, and the fast before a blood test all have different rules. We make creatine gummies, and ours aren't zero-calorie, so we'll show you our own label too.

The short version

Plain creatine powder in water doesn't contain carbs, fat or protein, and it doesn't raise insulin on its own. For an intermittent fast, it's fine.
Gummies, flavoured powders and pre-workouts can break a fast. GUMO gummies have 147 kJ and 8.6g of carbohydrate per serve, so take them in your eating window if your fast is strict.
No human study has tested creatine and autophagy. The claim that creatine switches on mTOR comes from a study that actually found the opposite.
For Ramadan, anything you swallow counts, so take creatine at suhoor or iftar. Before surgery, gummies count as solid food.
Creatine and fasting can both raise creatinine on a blood test. Tell your doctor you take it.

Does creatine break a fast?

Plain creatine doesn't break a fast in any way that matters for most people, but it depends on how you define "breaking" it.

Most people fasting are going by one of three rules. Calories: anything with energy breaks the fast. Insulin: anything that raises insulin breaks the fast, because keeping insulin low is the point for a lot of people. Or a set of religious or medical rules, where swallowing anything at all counts. Plain creatine passes the first two easily and fails the third.

Creatine isn't a carbohydrate, a fat or a protein. Your body makes it from three amino acids and stores it mostly in your muscles, where it helps recycle energy during short, hard efforts. If you're new to it, our guide to what creatine is and how it works covers the basics.

One error to clear up: a top-ranking article calls creatine "a peptide" and suggests it probably carries the same calories as protein. It isn't a peptide. It's made from amino acids, but it isn't a chain of them. Australia's food labelling rules list energy values for protein, fat, carbohydrate and a handful of specific ingredients, and creatine isn't one of them.

Does creatine spike insulin?

No, not on its own. The best direct test is a 1996 study by Green and colleagues. Twenty-four men took 5g of creatine four times a day for five days, either dissolved in water or followed by 93g of sugar. The researchers reported that creatine alone "had no effect on serum insulin concentration". Adding the sugar sent insulin soaring.

Longer studies point the same way, with a twist. In a 2008 trial of 22 inactive men doing aerobic training, about 10g of creatine a day for three months improved glucose tolerance and didn't change fasting insulin. A 2003 study in vegetarians also found no change in the insulin response after six weeks, although blood sugar after a glucose drink was actually a little higher with creatine. So "creatine improves blood sugar" is overselling it. "Creatine doesn't raise insulin" is fair.

Does creatine break a fast for autophagy?

Nobody knows, because no one has tested it in people. A search of PubMed for creatine and autophagy in humans turns up no trials at all.

Autophagy is your cells' clean-up process. A 2014 review in Cell Research explains that it ramps up when nutrients run low, and that it's controlled by nutrient-sensing signals, including a pathway called mTOR that responds to amino acids. One popular article claims creatine activates this pathway and cites a 2008 study by Deldicque and colleagues as the proof. We read it. Nine people took creatine or a placebo for five days, with muscle samples taken after an overnight fast. Creatine lowered the activity of Akt, a step on the way to mTOR, by 60% at rest, and the authors concluded that five days of creatine didn't boost this growth signalling at all. That's close to the opposite of what the article says.

The only study we found that measured autophagy directly was in mice on a high-fat diet, and there creatine increased a type of autophagy in fat and liver tissue. Mouse results often don't carry over to people, so we'd call the whole question open.

My take: if autophagy is the main reason you fast, take creatine in your eating window. It costs you nothing, because creatine works by building up in your muscles over weeks, not by timing.

Do creatine gummies break a fast?

Usually, yes. Gummies need something to make them taste good and hold their shape, and that something tends to have energy. Here's how the common formats compare.

Format	Energy and carbs	Intermittent fast (16:8)	Strict zero-calorie or autophagy fast	Ramadan
Plain creatine powder in water	Close to zero	Fine	Fine for calories; autophagy untested	Breaks it
Flavoured powder or pre-workout	Check the label: anything from zero to dextrose	Depends on the label	Usually take in eating window	Breaks it
GUMO creatine gummies (4 gummies)	147 kJ, 8.6g carbohydrate, 0g sugars	Small effect; best in eating window	Breaks it	Breaks it
Creatine mixed with juice or a protein shake	Plenty	Breaks it	Breaks it	Breaks it

Does creatine break your fast: plain creatine powder in water is fine for an intermittent fast, GUMO creatine gummies have 147 kJ and 8.6g carbohydrate per serve so are best taken in your eating window, and during Ramadan any creatine should be taken at suhoor or iftar

What's in our gummies

I'll be upfront: I don't fast, and nobody has ever asked us whether GUMO breaks a fast. But when we pulled out our own label for this guide, the answer was clear. A serve of four GUMO gummies has 147 kJ (about 35 calories), 8.6g of carbohydrate and 0g of sugars. The carbohydrate is maltitol syrup, a sugar alcohol, and the gummies are also sweetened with a little stevia and sucralose. So they don't fit a strict zero-calorie fast, and we'd rather tell you that than pretend otherwise.

Maltitol is gentler on blood sugar than sugar, but it isn't nothing. A 2003 review of sugar alcohols gave maltitol a glycaemic index of 35 and an insulin index of 27, compared with 65 and 43 for table sugar and 100 for glucose. In other words, gram for gram it has well under half the blood sugar effect of glucose. Energy-wise, the Australia New Zealand Food Standards Code counts maltitol as 13 kJ per gram, against 17 kJ for ordinary carbohydrate.

If you're doing 16:8 for weight loss, 147 kJ is small next to everything else you'll eat that day, and I wouldn't stress about it. If you're doing a strict water fast, a fast for autophagy, or you're keto and counting every gram, take your gummies with your first meal.

Sweeteners and "cephalic" insulin

Some people avoid sweet tastes during a fast altogether. There's a reason for that: a 2020 meta-analysis found the body can release a small amount of insulin within minutes of simply tasting or smelling food. How much sweeteners alone trigger it isn't settled. For a strict fast, it's one more reason to keep sweet-tasting supplements to your eating window.

Can you take creatine on an empty stomach?

Yes. The main thing that upsets stomachs is the dose, not the timing: a 2008 study in athletes found 10g in one go caused diarrhoea far more often than two 5g doses. The Australian Institute of Sport suggests skipping the loading phase and taking creatine with meals to avoid it.

So if you fast, a standard 3 to 5g dose in water is the gentlest option. Don't try a 20g loading phase on an empty stomach. Our guide to the creatine loading phase explains why you don't need one.

Does creatine still work if you take it while fasting?

Yes. A common claim on fasting forums is that creatine needs insulin to get into your muscles, so taking it fasted is a waste. The research says otherwise.

In the same Green study, the men who took creatine in plain water still increased the creatine and phosphocreatine in their muscles. The group that added 93g of sugar stored about 60% more, which is where the "take it with carbs" advice comes from. But that was during a five-day loading phase at 20g a day. At a normal 3 to 5g a day, the AIS says your muscles fill up over about four weeks without loading, and what matters is taking it every day. More in when to take creatine.

Does creatine break a fast for blood work?

For the fast itself, plain creatine in water usually isn't a problem. For the results, it can be. Creatine breaks down into creatinine, which is what labs use to estimate how well your kidneys are working.

Kidney Health Australia's 2024 handbook for GPs lists "creatine supplements" among the situations where an eGFR, the kidney score on your blood test, may be "unreliable and/or misleading". Fasting can push creatinine up too. In a 2023 study of 24 healthy young adults, a 24-hour fast raised serum creatinine by 14.7% on average. Put the two together and healthy kidneys can look worse on paper than they are.

Creatine, fasting and your blood test: creatine breaks down into creatinine, a 24-hour fast raised creatinine by 14.7% in a 2023 study of 24 adults, and Kidney Health Australia lists creatine supplements as a reason eGFR can mislead, so tell your doctor you take creatine

Don't stop or change anything because of this article. Instead, follow the instructions for your test, and tell your doctor or the collection centre that you take creatine. Healthdirect notes that some tests need you to change how you take a supplement beforehand, and that results are read in light of the supplements you take. If you're curious about the difference between the two, see creatine vs creatinine, and the kidney section of our creatine side effects guide.

Can you take creatine during Ramadan?

Yes, but at suhoor or iftar, not during daylight hours. The Australian Islamic Medical Association notes that medications which "enter the digestive system break the fast", including tablets and syrups, and creatine is no different. Take your usual dose with either meal. Because creatine works by keeping your muscle stores topped up, the time of day doesn't change how well it works.

Does creatine count as food before surgery?

Gummies do. The Australian and New Zealand College of Anaesthetists says to stop solid food at least six hours before surgery, and warns that lollies and mints are a risk if inhaled. Treat creatine gummies the same way, and ask your anaesthetist or pre-admission clinic about any supplement you take, including powder.

Should you keep taking creatine on a long fast?

There's no research on creatine during multi-day fasts, so this is a judgement call. If you stop for a few days, not much changes: the International Society of Sports Nutrition says it generally takes 4 to 6 weeks for muscle creatine to return to normal after stopping. Plain creatine in water is the option that fits most fasting rules if you'd rather keep going.

If you're planning a fast longer than a day or two, it's worth talking to your GP first, especially if you take any regular medication.

Four creatine monohydrate gummies give you the full 5g in one go. If you fast, they're simplest to take with your first meal.

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've shown you our own label, which doesn't fit a strict fast.

5g of creatine with your first meal. Four GUMO Creatine Gummies give you 5g of creatine monohydrate with no sugar, and every batch is lab tested in Australia with the results published. Rated 4.9 stars from 500+ reviews.

Shop GUMO creatine gummies →

Frequently asked questions

Can I take creatine while fasting?

Yes, if it's plain creatine monohydrate in water and your fast is about calories or insulin. It contains no carbs, fat or protein, and studies haven't found it raises insulin. For Ramadan, before surgery or a strict autophagy fast, take it in your eating window.

Does creatine break ketosis?

Plain creatine contains no carbohydrate, so there's no reason it would. Flavoured powders and gummies may contain carbs; GUMO gummies have 8.6g per serve from maltitol syrup, so count them if you're on strict keto.

Does creatine break autophagy?

No human study has tested it. The study often cited to show creatine switches on mTOR actually found creatine lowered that signalling at rest. If autophagy is your goal, taking creatine with food is the cautious option and doesn't reduce its benefits.

Does flavoured creatine break a fast?

It depends on the label. Some flavoured powders use zero-energy sweeteners, others add dextrose or maltodextrin, which will break any fast. Check the energy and carbohydrate lines on the nutrition panel, not the front of the pack.

Why did I gain weight after starting creatine?

Mostly water stored in your muscles. The AIS puts the gain at up to about 1 to 2kg. It isn't fat, but it can make the scales confusing if you're fasting to lose weight.

Can I take creatine with black coffee while fasting?

If your fasting rules allow black coffee, adding plain creatine doesn't change much, since creatine alone has no carbohydrate and didn't raise insulin in studies. Our guide to creatine in coffee covers what the research says about caffeine.

Should I stop creatine before a blood test?

Follow your doctor's or the pathology collection centre's instructions, and tell them you take creatine. It can raise creatinine and make your kidney results look worse than they are, which Kidney Health Australia lists as a known reason eGFR can mislead.

Are there benefits to taking creatine while fasting?

No study has tested creatine during intermittent fasting specifically. The closest is a 2026 trial in adults aged 45 to 65 on a calorie-reduced diet with exercise, where those taking 10g of creatine a day lost more body fat percentage than those on a placebo. People chose for themselves whether to join the diet and exercise group, though, so treat it as a promising sign rather than proof. More in creatine and fat loss.

We keep this guide up to date

22 October 2026: guide published. Reviewed by Koji Wang.

23 October 2026: every source re-checked against the original study, a few figures corrected, and new questions answered. Reviewed by Koji Wang.

Sources

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 →

Roy AndersonGumo Performance