Both of these show up constantly in the same conversation, usually because someone tried LMNT, found it too salty or too expensive, and started looking for an alternative. Instant Hydration is the one that comes up most often. The two products are built on genuinely different philosophies rather than one just being a cheaper copy of the other, so a real side-by-side is more useful than a "which one is better" verdict. Here's what's actually in each one, and I'll flag where I think the comparison misses something if what you're using electrolytes for is fasting rather than general hydration.

What Actually Matters When You're Comparing Two Electrolyte Products

Sodium, potassium, and magnesium as real milligram numbers. Not a "mineral blend" hiding behind a single combined figure. Both of these brands are decent about this, which already puts them ahead of a lot of the category.

Calories. Zero-calorie is the assumption most people bring to this category, so it's worth checking rather than assuming.

What's sweetening it. Stevia is the industry default. Monk fruit shows up less often. Neither is dangerous, but if you're trying to keep sugar cravings quiet or you're strict about what touches your fasted state, the sweetener matters.

Sodium source. Standard sodium chloride versus an unrefined salt that carries trace minerals along with it. Cosmetic to some people, meaningful to others.

Price per serving, because clean formulation costs money and it's fair to know what you're paying for it.

LMNT

• Sodium: 1,000mg

• Potassium: 200mg

• Magnesium: 60mg

• Calories: 0

• Sweetener: Stevia leaf extract

• Natural flavors: Yes

• Price: About $1.50 per serving

LMNT's entire formula is built around one number: sodium. A thousand milligrams in a single stick is more than double what Instant Hydration carries, and it's aimed squarely at people who sweat heavily, train hard, or run longer fasted or low-carb stretches where sodium loss is the dominant concern. Potassium and magnesium are both present but modest next to the sodium dose. The sodium itself is standard sodium chloride, not a sea salt, so what you're getting is sodium and chloride and nothing else riding along with it. There's stevia and natural flavors in the mix, and the formula doesn't try to do anything beyond the three electrolytes. If your only question is "which one replaces the most sodium in one serving," LMNT wins that question outright.

Instant Hydration

• Sodium: 500mg

• Potassium: 470mg

• Magnesium: 100mg

• Calcium: 170mg

• Calories: 10

• Sweetener: Organic stevia leaf extract and organic monk fruit extract

• Natural flavors: Yes

• Price: About $1.65 to $1.85 per serving one-time, lower with a subscription

Instant Hydration spreads the dose out instead of maxing out one mineral. Potassium comes in more than double LMNT's, magnesium nearly double, and it adds calcium, which LMNT doesn't include at all. The sodium source is Sel Gris, a French grey sea salt the brand markets as carrying trace minerals along with the sodium, similar in spirit to what Redmond's Re-Lyte does with Real Salt. Where it splits from LMNT is the sweetener and the calorie count: it uses both organic stevia and organic monk fruit rather than stevia alone, and it isn't actually zero-calorie. Ten calories a stick is small, but it's not nothing, and it's worth knowing if you're using this during a strict caloric fast rather than just for general hydration. It's also priced higher than LMNT per serving at full price, though the brand's subscription discounts can bring that down meaningfully.

How They Actually Compare

If you want the single highest sodium dose available and don't mind paying for it, LMNT is still the more direct answer, and nothing about Instant Hydration's broader mineral spread changes that. If you want potassium, magnesium, and calcium alongside a lighter sodium dose, and you don't mind two sweeteners and a small calorie count, Instant Hydration is the more complete mineral profile of the two. Neither is doing anything dishonest with their labels, which is more than you can say for a lot of the category. The real difference is philosophy: LMNT bets everything on sodium being the mineral that matters most, Instant Hydration bets on covering four minerals at once and accepting a small calorie tradeoff to get there.

Where Fasting Changes the Calculus

Here's the part that doesn't show up in either brand's marketing, because neither one is built with fasting specifically in mind. Both of these are designed around a single serving: one big dose before a workout, one stick in a water bottle for the day. That's a reasonable way to think about hydration generally. It's a less complete way to think about a fasting window, where the demands change from the first hour to the twelfth.

LMNT's sodium ceiling is the more obvious issue for a faster who takes electrolytes more than once. General guidance caps daily sodium around 2,300 milligrams, and two servings of LMNT alone puts you at 2,000 of that before you've eaten anything. That's fine for one hard training session. It's not something you want to be doing morning, midday, and pre-refeed. Instant Hydration's lighter sodium dose gives you more room there, but its 10 calories a stick means it isn't technically calorie-free if you're fasting for autophagy or a true caloric deficit rather than just staying low-insulin, and the added sweetness from two different sources is more to weigh if part of your goal is letting sugar cravings actually settle during a fast.

Neither product addresses anything past the mineral question either. Fasting fog, blood sugar swings before you break your fast, digestion once your gut has gone quiet for half a day, none of that is what either of these formulas was built to do. That's the gap Optimize was built to close: zero sugar, zero calories, no sweeteners of any kind so there's nothing to weigh against a strict fast, and a formula light enough to use more than once through a fasting day without running into the ceiling the higher-dose products hit. L-theanine for the mental fog that shows up hours into a fast, Ceylon cinnamon for blood sugar support, ginger and lemon peel for digestion once you're ready to eat again. It doesn't carry LMNT's single-serving sodium peak or Instant Hydration's four-mineral spread, and I'd rather tell you that directly than pretend it wins a fight it wasn't built for. What it's built for is the parts of a fasting day neither of these products is thinking about at all.

The Bottom Line

If you're comparing these two for general hydration, hard training, or everyday electrolyte use, the choice comes down to whether you want maximum sodium in one dose or a broader mineral spread with a small calorie tradeoff. Both are honest, reasonably formulated products. But if the reason you're reaching for electrolytes is a fasting window specifically, the more useful question usually isn't LMNT versus Instant Hydration at all. It's whether either one was built for a fast in the first place, and what electrolytes are actually doing for you during one.

Fuel your fast, feel your best.

Sources and Further Reading

Sodium and Potassium: Effects on Health https://www.cdc.gov/salt/sodium-potassium-health/index.html

Potassium: Fact Sheet for Health Professionals, National Institutes of Health, Office of Dietary Supplements https://ods.od.nih.gov/factsheets/Potassium-HealthProfessional/

Best Electrolyte Drinks for Fasting: An Honest Comparison, Fasted State Supplements https://getfastedstate.com/blogs/news/best-electrolyte-drinks-for-fasting

The Truth About Stevia and Fasting, Fasted State Supplements https://getfastedstate.com/blogs/news/the-truth-about-stevia-and-fasting