Draft
Does electrolytes break a fast?
Unflavoured, unsweetened electrolytes — sodium, potassium and magnesium — do not break a fast. They contain no calories and do not raise insulin. Most commercial electrolyte sachets are not pure: many contain sugar, dextrose or added flavourings that do break a fast, so the answer depends on the specific product.
| Fasting for | Verdict | Why |
|---|---|---|
| Weight loss | Depends | Pure mineral salts are calorie-free. Many sachets contain 5 to 15 g of sugar, which is not. |
| Autophagy | Depends | Minerals alone do not activate mTOR. Products containing amino acids or sugar do. |
| Blood work | Depends | Can affect sodium, potassium and glucose panels. Ask the clinic. |
| Ketosis | Depends | Pure electrolytes support ketosis. Sugar-containing sachets interrupt it. |
| Gut rest | Doesn't break it | Minimal digestive load in mineral form. |
Why
Sodium, potassium and magnesium are minerals, not energy substrates. They pass through no metabolic pathway that yields calories or provokes insulin release. Replacing them during an extended fast is often actively recommended, because the drop in insulin during fasting increases renal sodium excretion, which is a common cause of fasting headaches and fatigue.
Approximately 0 kcal for pure mineral salts. Commercial sachets vary from 0 to 60 kcal.
The exceptions
This is usually where the real question lives.
- Check the label rather than the marketing. Several popular sachets contain added sugar or dextrose.
- Products containing BCAAs or amino acids do break a fast for autophagy purposes.
- Sugar-free versions using stevia or monk fruit are a separate question — see those pages.
Sources
Not yet sourced. Primary references are added before an entry is reviewed and indexed.
Awaiting clinical review.
Last updated 2026-08-15.
Related
Fasting Index sells no supplements and takes no affiliate revenue. General information only, not medical advice.