Best Electrolytes for Keto, Fasting, and GLP-1

Electrolytes come up constantly in keto, intermittent fasting, and GLP-1 medication communities for the same underlying reason: all three change how much sodium, potassium, and water your body holds onto. Keto and fasting lower insulin, which causes the kidneys to excrete more sodium. GLP-1 medications slow digestion and reduce appetite, which can mean less fluid and electrolyte intake overall, especially if nausea is part of the picture.

Here’s how five widely recommended electrolyte products actually differ — because “electrolytes” is not a single product category, and the sugar content varies enormously.

Quick comparison

Figures are typical values and vary by flavor/line — check the current label, especially for Liquid I.V. and Pedialyte, which both sell separate zero-sugar versions.

The picks, in more detail

LMNT

A zero-sugar stick-pack mix with a notably high sodium dose, built specifically for the keto/low-carb and endurance-athlete crowd.

• Pros: Zero sugar, strong flavor despite no sweetener beyond stevia, convenient single-serve packets, popular sampler packs for trying flavors.
• Cons: ~1,000mg sodium per stick is a lot in one serving — not ideal if you’re sodium-sensitive or managing blood pressure; sold mostly through subscription, which can cost more than one-off purchases.
• Best for: Keto, carnivore, and fasting dieters, or high-sweat athletes who want a strong, zero-sugar sodium dose.
• Typical price: ~$1.50–2.00 per stick pack (subscription discounts available).

Ultima Replenisher

A zero-sugar, stevia-sweetened powder with a fuller six-electrolyte spectrum but a much lower sodium dose than LMNT.

• Pros: Zero sugar and calories, broader mineral spread (sodium, potassium, magnesium, calcium, phosphorus, chloride), lighter “water-like” taste that’s easy to drink often, vegan/allergen-friendly.
• Cons: Low sodium may not be enough on its own during intense keto-flu symptoms or heavy sweating; less of a sodium “punch” than LMNT if that’s specifically what you need.
• Best for: Everyday hydration and people who want a lighter, lower-sodium option they can drink multiple times a day.
• Typical price: ~$20–25 for a 30-serving canister (roughly $0.70–0.85 per serving).

Nuun Sport

Effervescent tablets you drop into a water bottle — built primarily for athletes, with several spin-off lines (Sport, Rest, Immunity).

• Pros: Very portable (a tablet tube fits in any bag), low calorie, wide flavor range, established brand with a long track record.
• Cons: Lower sodium than LMNT (may not be enough for strict keto-flu relief); some lines carry a small amount of sugar/carbs; fizzy texture isn’t for everyone.
• Best for: Athletes and travelers who want a compact, portable tablet format.
• Typical price: ~$7–8 per tube of 10 tablets (roughly $0.70–0.80 per serving).

Pedialyte

Originally a pediatric rehydration solution, now sold in adult-marketed “Sport” and “Zero Sugar” lines too, with a sodium-glucose ratio specifically designed for fast absorption during illness.

• Pros: Gentle on the stomach, purpose-built for rehydration during nausea/vomiting/illness, widely available in pharmacies and grocery stores, Zero Sugar line is keto-compatible.
• Cons: The original formula does contain sugar (not keto-friendly); tastes more “clinical” than sport-drink competitors to some people; not formulated around athletic performance.
• Best for: GLP-1 nausea support, illness recovery, or anyone who needs a gentler rehydration option than a sports drink.
• Typical price: ~$6–10 per 1L ready-to-drink bottle, or ~$10–12 for a powder-packet box.

Liquid I.V.

Powder stick packs built around “Cellular Transport Technology” — a specific sugar-sodium-potassium ratio designed to pull more fluid into the bloodstream than water alone.

• Pros: Strong, pleasant flavor; widely available (grocery stores, Costco, Amazon); Zero Sugar line available for low-carb users; well-known, trusted brand.
• Cons: The original formula carries meaningfully more sugar (~11g) than the other options here — not ideal for strict keto unless you pick the Zero Sugar version specifically.
• Best for: General travel or everyday hydration when carbs aren’t a primary concern, or the Zero Sugar line if they are.
• Typical price: ~$1–1.50 per stick pack in multi-packs.

How to actually choose one

If you’re strict keto or fasting

LMNT and Ultima Replenisher are both zero-sugar and built specifically for the “keto flu” sodium deficit — the main difference is sodium load. LMNT packs roughly 1,000mg of sodium per stick, which is a lot in one serving; Ultima runs much lower and leans more on potassium and magnesium. If you already eat salty foods, Ultima may be the better fit; if you’re cutting sodium from food entirely, LMNT’s higher dose can be useful.

If you’re managing GLP-1 side effects

Nausea and reduced intake are common early on GLP-1 medications, and that’s exactly the scenario Pedialyte was designed for — it’s formulated to be gentle and easy to tolerate, with a glucose-sodium ratio built for absorption during illness. The original formula does contain sugar, so the “Zero Sugar” version is the better match if you’re also watching carbs.

If you just want convenient everyday hydration

Nuun’s tablet format is easy to toss in a bag, and Liquid I.V.’s “cellular transport technology” formula (a specific sugar-sodium-potassium ratio) is designed to help you absorb fluid faster than water alone — useful for travel or general dehydration, less useful if you’re strictly limiting carbs.

Watch for over-supplementing sodium

More electrolytes isn’t automatically better. If you have high blood pressure, kidney issues, or take medication that affects sodium/potassium balance, talk to your doctor before adding a high-sodium product like LMNT daily.

Frequently asked questions

Do I need electrolytes on keto?

Many people do, at least during the first few weeks. Low-carb diets drop insulin levels, which causes the kidneys to release more sodium (and water) than usual — this is the main driver of “keto flu” symptoms like headaches and fatigue.

Are electrolyte drinks safe with GLP-1 medications?

Generally yes, and many people find them helpful for nausea and reduced fluid intake — but check with your prescribing provider, especially if you have any kidney, heart, or blood pressure conditions.

LMNT vs. Pedialyte — which is better?

They’re built for different problems. LMNT is a high-sodium electrolyte mix aimed at active, low-carb people. Pedialyte is a gentler rehydration formula originally designed for illness and is often better tolerated when you’re nauseated.

How much sodium is too much in an electrolyte drink?

There’s no single safe number for everyone — it depends on your baseline diet, activity level, and any health conditions. If you have hypertension or kidney disease, talk to a healthcare provider before adding a high-sodium product to your routine.