Best Electrolyte Powders for Fasting 2026: 5 Brands With Zero Carbs, Zero Sweeteners (Most Will Break Your Fast)

Jump to product picks ↓

As an Amazon Associate, I earn from qualifying purchases. Learn more.

Why Most Electrolyte Powders Will Break Your Fast

Almost every label says “zero sugar.” Read the back. Nine out of ten contain stevia, monk fruit, sucralose, erythritol, allulose, or a maltodextrin carrier — and several add 1 to 4g of “other carbohydrate” from gum arabic, modified starch, or citric acid blends. None are insulin-neutral in the strict fasting sense.

Sweet taste alone — even from a zero-calorie source — can trigger what physiologists call the cephalic phase insulin response: tongue tastes sweet, vagus nerve signals the pancreas, small insulin bolus before any nutrient hits the blood. Small but real, and enough to blunt the autophagy and growth-hormone elevations that make extended fasting worthwhile. Citric acid and “natural flavors” can engage the same receptors.

Then there’s the carbohydrate question. A 4g sugar serving is 16 calories — negligible by itself, but enough fast-absorbing glucose to spike insulin in most adults. We’ve seen this on continuous glucose monitor traces in our CGM testing guide, where a few grams of dextrose produces a 20–30 mg/dL rise within 20 minutes on a fasted baseline. That’s the difference between staying in ketosis and dropping out.

The true fasting bar: no sugar, no sugar alcohols, no sweeteners (natural or synthetic), no sweet-receptor flavor compounds, ideally no citric acid. Sodium, potassium, magnesium, and trace minerals only. Five products in this guide meet that bar — one barely, and one we include specifically so you know to leave it on fast days.

At a Glance

• Best Overall (Fasting Hero): LMNT Recharge Citrus Salt — 1000 mg sodium, no sweeteners, no carbs, the cleanest mainstream option
• Best Truly Unflavored: Redmond Re-Lyte Unflavored — full sodium-potassium-magnesium-chloride profile, no flavor, no sweetener, mix into anything
• Best Liquid for Strict Fasts: Buoy Electrolyte Drops — no sugar, no sweeteners, 87+ trace minerals, drips into water or coffee
• Best Budget Concentrate: Trace Minerals 40,000 Volts — ionic mineral concentrate, 48 servings for under $20, no sweetener
• NOT Fasting-Safe (Endurance Only): SaltStick FastChews — contains sugar, do not use during fasts but excellent fed-state endurance chew

The Fasting Electrolyte Checklist: Zero Carbs, Zero Sweeteners, Right Sodium Ratio

Before we get into the reviews, here is the standard we used. Any electrolyte you plan to use during a fast should answer yes to all five:

1. Zero grams of carbohydrate per serving — including “other carbs” from gums, starches, or carrier maltodextrin.
2. Zero sweeteners — no stevia, monk fruit, sucralose, aspartame, erythritol, allulose, or xylitol. Even “natural” sweeteners trigger cephalic responses.
3. Zero flavor additives capable of sweet/sour signaling — preferred. We made one exception for LMNT because its citric acid load is low and the salt content dominates the taste profile.
4. At least 800 mg sodium per serving — the minimum dose Volek and Phinney’s Art and Science of Low Carbohydrate Living recommends for fat-adapted and fasting adults.
5. Real magnesium and potassium — not trace amounts. Aim for 200+ mg potassium and 60+ mg magnesium per serving, ideally as glycinate or malate forms rather than oxide.

Comparison Table

*40,000 Volts is a mineral concentrate. It delivers potassium and magnesium but minimal sodium — pair with a pinch of pink salt for a full fasting stack.

Detailed Reviews

BEST OVERALL

1. LMNT Recharge — Citrus Salt

4.7★ (6,600+ reviews)

$44.97 (30 sticks)

Key Features:

• 1000 mg sodium, 200 mg potassium, 60 mg magnesium per stick
• Zero sugar, zero sweeteners (artificial or natural — no stevia, no monk fruit)
• Ingredients: salt, potassium chloride, magnesium malate, citric acid, malic acid, natural citrus flavor
• Formulated by Robb Wolf for keto and fasting athletes
• $1.50/stick full price; ~$1.27 with Subscribe & Save

Pros:

• Highest sodium dose in any mainstream electrolyte powder
• Genuinely zero sweetener — most “no sweetener” claims fail on close reading; LMNT doesn’t
• Citrus Salt has the lowest citric acid load of all LMNT variants
• Most-trusted brand in the fasting community

Cons:

• $1.50/serving is ~5x the cost of a DIY salt + potassium + Mg stack
• Contains citric acid — true purists should choose Re-Lyte Unflavored
• 1000 mg sodium is a lot on non-fast days if you eat the standard American diet

Why it’s #1: LMNT is the default fasting electrolyte for good reason. Right sodium dose, no sweetener, no carbs, and the brand has been formulated from day one for the keto and fasting audience rather than the general hydration market. Citrus Salt keeps citric acid low enough that salt dominates the taste, minimizing any cephalic signaling. If you buy one product on this list, buy this one.

Check Price on Amazon →

BEST PURIST PICK

2. Redmond Re-Lyte Unflavored

4.5★ (3,200+ reviews)

$39.95 (60 servings)

Key Features:

• 810 mg sodium, 400 mg potassium, 120 mg magnesium, plus chloride and trace minerals per serving
• Zero sweetener, zero flavor, zero citric acid — the strictest formula on this list
• Made from Redmond Real Salt (ancient sea bed in Utah) — same source as Redmond’s table salt product
• 60 servings per tub at roughly $0.67 per serving — best cost-per-mg of any clean-label option
• Mixes into water, coffee, tea, broth, or anything else — no flavor to fight

Pros:

• Highest potassium dose on this list (400 mg) — closer to the 1000 mg/day RDA most fasters undershoot
• 120 mg magnesium is double LMNT’s, which matters for extended fasts (magnesium deficiency drives cramps and insomnia by day 3+)
• Zero flavor means zero sweet-receptor signaling — the closest thing to “pure mineral water” you can buy
• Cheapest per-serving cost of any genuinely clean-label option

Cons:

• Unflavored is actually salty-mineral tasting — some users find it unpleasant in plain water (mix into coffee or sparkling water instead)
• Does not dissolve as cleanly as LMNT — leaves slight sediment if undermixed
• Less brand recognition outside the keto community

Why it’s here: If LMNT is the popular pick, Re-Lyte Unflavored is the purist pick. Shorter label, higher potassium and magnesium, and no citric acid or natural flavor — the only product here we’d call “absolutely zero sweet signal.” For 48+ hour fasts, the higher mag and potassium matter; those are the electrolytes that drop first.

Check Price on Amazon →

BEST LIQUID

3. Buoy Electrolyte Drops (3-Pack)

4.2★ (1,800+ reviews)

$39.95 (120 servings)

Key Features:

• No sugar, no sweeteners (any kind), 87+ trace minerals, vitamins, and antioxidants per dropper serving
• Liquid format — 6 to 8 drops per glass of water, coffee, or tea
• Lower per-serving sodium (~16 mg) but designed to be added to multiple drinks throughout a fast
• “Purposefully unflavored” — subtle mineral taste, no sweet-receptor signaling
• 120 servings per 3-pack at ~$0.33 per serving — cheapest electrolyte on this list per dose

Pros:

• The only liquid option here — drips directly into your morning coffee without changing the flavor
• No sweet-receptor activation at all, which makes it the safest pick for autophagy-focused fasts
• Travel-friendly — one small bottle replaces an entire box of sticks
• Dietitian-recommended formula with antioxidants and trace minerals beyond just Na/K/Mg

Cons:

• Low sodium per serving — you need to stack it with a pinch of pink salt if you want a full 800+ mg sodium dose
• Subtle mineral taste in plain water can be off-putting; works better in coffee
• The 3-pack is only worthwhile if you actually use it daily — single bottles are better for trials

Why it’s here: Buoy is the pick for the strictest fasters — the ones who won’t use LMNT because they worry about citric acid signaling. The drops are genuinely flavorless and let you “salt your coffee” without ending the fast. The catch is low sodium per dose, so stack with a quarter teaspoon of Redmond Real Salt for 36–72 hour fasts.

Check Price on Amazon →

4. Trace Minerals 40,000 Volts Concentrate

4.5★ (6,300+ reviews)

$19.99 (48 servings)

Key Features:

• ~250 mg magnesium and 250 mg potassium per teaspoon serving (highest mag/K of any liquid)
• Ionic mineral concentrate from the Great Salt Lake — 72+ trace minerals
• Zero sugar, zero sweeteners, zero flavor additives
• 48 servings per 8-ounce bottle — under $0.42 per serving
• Strong mineral taste — better used in 16+ oz of water or in broth

Pros:

• Cheapest legitimately clean-label option on this list at under $20
• Massive magnesium dose — better than any other product here for the 3rd-day cramp prevention problem
• Vegan, non-GMO, gluten-free, made in the USA
• One bottle lasts 6+ weeks for daily users

Cons:

• Effectively zero sodium per serving — must be paired with salt for a true fasting electrolyte stack
• Concentrated mineral taste is strong and salty-bitter; not enjoyable in plain water
• Brand is more associated with general “trace mineral wellness” than fasting specifically — easy to misuse the dosing

When to choose it: 40,000 Volts is the budget hack. Combine half a teaspoon (250 mg Mg, 250 mg K) with a quarter teaspoon of Redmond Real Salt (~575 mg sodium) and you’ve re-created an LMNT stick for under $0.50. Trade is taste and measuring two ingredients. Also works as a standalone magnesium source on non-fast days — see our magnesium glycinate gummies guide for chewable alternatives.

Check Price on Amazon →

DO NOT USE WHILE FASTING

5. SaltStick FastChews (Endurance Use Only)

4.6★ (1,700+ reviews)

$19.95 (60 chews)

Key Features:

• 200 mg sodium, 60 mg potassium, 22 mg magnesium, 11 mg calcium per 2-chew serving
• Contains sugar and dextrose — about 3g carbs per serving
• Designed for endurance athletes (runners, cyclists, triathletes) who are NOT fasting
• Chewable tablet format — no water required

Pros:

• Best-in-class for hot-weather endurance work and post-meal hydration
• Chewable format is excellent when you cannot stop to mix a drink
• Highly rated and widely used by competitive athletes
• Useful in your stack on non-fast training days

Cons:

• Will break a clean fast — the 3g of carbs from real sugar will spike insulin and end ketosis
• Sweetened with sugar and dextrose, plus natural flavors and citric acid
• Sodium per serving is too low for true fasting electrolyte replacement anyway

Why we included it: FastChews show up in every “best electrolytes for fasting” listing on Google — and they shouldn’t. The product is good, just for a different use case. Long run or HIIT in the middle of a fed day? Reasonable pick. 18 hours into a fast? Choose any of the four products above instead.

Check Price on Amazon →

The Sodium Math: How Much You Actually Need While Fasting

The biggest mistake new fasters make is undershooting sodium. Twenty years of public-health messaging trained us to fear salt — but during a fast, with no food and no carbs to retain water, your kidneys aggressively excrete sodium. Within 24 hours of starting a clean fast, you’re losing 1–3 grams per day in urine. The symptoms most people blame on “low blood sugar” — headache, fatigue, brain fog, dizziness, night cramps — are almost always low sodium, not low glucose.

Volek and Phinney’s keto-adaptation research targets 3–5 grams of sodium per day for fat-adapted and fasting adults — roughly 1.3 to 2.2 teaspoons of salt, or two to four LMNT sticks. Two doses (morning and afternoon) covers it.

For potassium, target 1000 mg daily (RDA), with 200–400 mg from supplementation while fasting. For magnesium, target 200–400 mg supplemental daily — Dr. Jason Fung specifically recommends magnesium glycinate or malate before bed to prevent the day-3 cramp and insomnia issue. Our magnesium glycinate gummies guide covers chewable options (most contain sweetener — read carefully).

Sweeteners and Fasting: Stevia, Monk Fruit, Sucralose — What Actually Spikes Insulin

Most fasting blogs get this wrong. The honest answer: it depends on what you mean by “break the fast.”

For pure caloric fasting, any zero-calorie sweetener is technically fine — Diet Coke all day still counts as a fast. For autophagy, deep ketosis, or metabolic flexibility, the rules change. The cephalic insulin response is real but small — meta-analyses show artificial sweeteners produce roughly 10–20% of the insulin response of actual sugar. Enough to slow autophagy, probably not enough to fully suspend it. Stevia in particular has shown small insulin-stimulating effects in several studies, which is why purists avoid it.

The practical hierarchy, cleanest to dirtiest:

• No sweetener (Re-Lyte Unflavored, Buoy, 40,000 Volts) — gold standard for autophagy fasts.
• Natural flavors, no sweetener (LMNT Citrus Salt) — fine for the vast majority of fasters.
• Stevia or monk fruit — small cephalic response; won’t break a caloric fast but may slow autophagy.
• Sucralose or aspartame — similar cephalic response, plus separate gut microbiome concerns.
• Erythritol, allulose, xylitol — not zero-insulin; allulose specifically has been shown to be insulinogenic.
• Sugar, dextrose, maltodextrin — fast break, end of discussion.

If you wear a CGM, run your own test: take your morning sweetener of choice on a fasted baseline and measure every 10 minutes for an hour. Some people see no response. Others see a 15–25 mg/dL spike from stevia alone. The Dexcom Stelo or Abbott Lingo is the cheapest way to measure rather than guess.

Liquid vs Powder Format

Powder sticks (LMNT, Re-Lyte): Best for accurate dosing — each stick is exactly 1000 mg sodium, no measuring. Throw in a gym bag. Downside is single-use packaging and higher cost per gram.

Powder tubs (Re-Lyte tub): Cheapest per serving by 40–60%. Best for daily home use. Need a measuring scoop and you commit to one flavor.

Liquid drops (Buoy, 40,000 Volts): Best for adding to drinks you’re already having — coffee, tea, sparkling water. Travel-friendly in small bottles. Trade is bitter mineral taste and less precise dosing.

Chewables (SaltStick): Best for endurance activity when you can’t mix a drink. Almost all contain sugar or sweetener — not fasting-appropriate.

For most fasters, the right stack is a powder for the primary morning dose plus a liquid for afternoon top-ups in coffee or sparkling water.

Who Should NOT Use Fasting Electrolytes

1–3g of supplemental sodium per day is safe for most healthy adults — but explicitly not for several groups. Talk to your doctor before supplementing, especially before any multi-day fast, if any of these apply:

• Kidney disease (any stage). Damaged kidneys can’t regulate sodium and potassium properly; hyperkalemia can be fatal.
• Uncontrolled or poorly controlled hypertension. 1000+ mg sodium per dose can spike blood pressure further.
• Heart failure, arrhythmia, or recent cardiac events. Sodium and potassium directly affect cardiac electrical activity. Get cardiologist clearance first.
• Pregnancy or nursing. Extended fasting isn’t recommended, and electrolyte balance during pregnancy needs OB-GYN management.
• Diuretic users (Lasix, HCTZ, spironolactone), lithium, ACE inhibitors, or ARBs. All alter sodium/potassium handling and can cause serious imbalances when combined with supplemental sodium.
• History of eating disorders. Fasting can mask or worsen restrictive patterns.
• Children and adolescents under 18. Extended fasting and supplemental sodium are not appropriate.

How We Picked These

We evaluated every fasting-positioned electrolyte on Amazon with 500+ reviews against six criteria:

1. Ingredient transparency — full disclosure of flavor and sweetener sources, not just “natural flavors.”
2. Zero-sweetener formulation — verified on the back panel, not the front-panel marketing.
3. Sodium dose — minimum 200 mg per serving (Buoy is the stacking exception); 800+ mg for hero products.
4. Real magnesium and potassium in bioavailable forms (glycinate, malate, citrate preferred over oxide).
5. Review depth — 1,000+ Amazon reviews, 4.0★+ average.
6. Brand track record — established makers with public formulation rationale.

We rejected over a dozen popular Amazon brands because they contained stevia, monk fruit, allulose, or undisclosed natural flavors — even though many wouldn’t technically break a caloric fast.

Frequently Asked Questions

Final Thoughts

The fasting electrolyte category is full of products that look fast-safe and aren’t. The five above survive a hard look at the back-panel ingredient list. LMNT Citrus Salt is the default — right sodium dose, no sweetener, strongest brand reputation. Re-Lyte Unflavored is the purist upgrade with the highest magnesium dose. Buoy Drops stack into coffee without changing the taste. Trace Minerals 40,000 Volts is the budget hack when paired with salt. And SaltStick FastChews are the reminder that “looks healthy” isn’t the same as “fast-safe.”

The honest summary: most fasters can run two doses of LMNT per day and be done. Strict autophagy purists should layer in Re-Lyte or Buoy for zero sweet signal. Anyone fasting beyond 36 hours should hit 3+ grams of sodium, 1000 mg potassium, and 300+ mg magnesium daily — or accept that the day-two headache is the salt they forgot, not the fast itself.