Does creatine break a fast?

Why plain creatine fits a fast

If you fast so that your body runs on stored fat, what matters most is keeping insulin low, because insulin tells your cells to store fuel rather than release it. Creatine isn't sugar, fat or a meal's worth of protein. Your muscles store it and use it to recharge their quick energy during hard efforts, such as a heavy lift or a sprint.

The clearest evidence comes from a study in Nottingham. Twenty-four men took 5 g of creatine four times a day for five days, either on its own or followed by a large sugary drink. Creatine alone had no effect on the insulin in their blood. Creatine with sugar sent insulin sharply up ¹.

Check what's in your tub

Product	While fasting
Creatine monohydrate powder in water	Fine
Capsules of plain creatine	Fine
Creatine gummies	Usually made with sugar: take them in your eating window
Pre-workouts and flavoured mixes	Check the label for sugar, carbohydrate or added protein
Creatine stirred into a shake or juice	Breaks your fast: it's the shake, not the creatine

When to take it

Creatine works by building up in your muscles over days and weeks, so taking it every day matters more than the hour you take it. The International Society of Sports Nutrition suggests 3 to 5 g a day to keep your muscles topped up, after an optional loading week of about 20 g a day split into four doses ².

• Fasting all morning? Stir it into a glass of water whenever it suits you.
• Want a little more of it to reach your muscles? Take it with your first meal: with carbohydrate, or carbohydrate and protein, muscles take up more creatine, though that may not make a difference to performance ^2,1.
• Training to keep muscle? Strength work and enough protein are what kept muscle and strength in people following 16:8 ^3,4. Creatine is an extra, not a replacement.

Is it safe to take while fasting?

For healthy adults, the same position stand found creatine safe and well tolerated, in studies of up to 30 g a day for as long as five years ². The side effect people notice most is a little weight gain: a loading week can hold around half a litre to a litre of extra water in your body. If you track your weight, expect a small jump that isn't fat.

MYTH

Creatine needs sugar to work, so it's pointless on an empty stomach.

FACT

Sugar helped men store more creatine in one study, but plain creatine raised their muscle stores too ¹. Taking it daily is what fills them up over time ².

Sources

1. Green AL, Hultman E, Macdonald IA, et al. Carbohydrate ingestion augments skeletal muscle creatine accumulation during creatine supplementation in humans. Am J Physiol. 1996;271(5 Pt 1):E821-6. doi.org/10.1152/ajpendo.1996.271.5.E821
2. Kreider RB, Kalman DS, Antonio J, et al. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. J Int Soc Sports Nutr. 2017;14:18. doi.org/10.1186/s12970-017-0173-z
3. Moro T, Tinsley G, Bianco A, et al. Effects of eight weeks of time-restricted feeding (16/8) on basal metabolism, maximal strength, body composition, inflammation, and cardiovascular risk factors in resistance-trained males. J Transl Med. 2016;14(1):290. doi.org/10.1186/s12967-016-1044-0
4. Tinsley GM, Moore ML, Graybeal AJ, et al. Time-restricted feeding plus resistance training in active females: a randomized trial. Am J Clin Nutr. 2019;110(3):628-640. doi.org/10.1093/ajcn/nqz126