Draft
Does creatine break a fast?
Pure creatine monohydrate does not break a fast. It contains no calories and does not raise insulin. Flavoured blends, creatine gummies, and creatine mixed with juice or milk do break a fast, because of what is added to them rather than the creatine itself.
| Fasting for | Verdict | Why |
|---|---|---|
| Weight loss | Doesn't break it | No calories, so it cannot affect an energy deficit. |
| Autophagy | Depends | Creatine is not an amino acid and is not strongly mTOR-activating, but direct human evidence on autophagy is thin. Strict autophagy fasters often skip it. |
| Blood work | Depends | Creatine raises serum creatinine, which can make kidney markers read falsely high. Tell the clinic you take it, and follow their instructions. |
| Ketosis | Doesn't break it | No carbohydrate, no effect on ketone production. |
| Gut rest | Depends | A powder in water is a minimal digestive load, but it is not nothing. |
Why
Creatine monohydrate is not metabolised for energy. It is taken up by muscle and phosphorylated to phosphocreatine, a process that neither yields usable calories nor triggers a meaningful insulin response. The two mechanisms that normally define "breaking a fast" — energy intake and insulin signalling — are therefore both absent.
Approximately 0 kcal per 5 g of pure monohydrate.
The exceptions
This is usually where the real question lives.
- Creatine gummies contain sugar or sugar alcohols and calories. These break a fast.
- Flavoured blends often contain maltodextrin or dextrose, both of which spike blood glucose.
- Pre-workout formulas containing creatine usually also contain BCAAs or carbohydrate, which do break a fast.
- Creatine taken with juice or milk breaks a fast because of the juice or milk.
Sources
Not yet sourced. Primary references are added before an entry is reviewed and indexed.
Awaiting clinical review.
Last updated 2026-08-15.
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