Most electrolyte labels are designed to look impressive while hiding the information that matters. Brands manipulate serving sizes and bury sodium content in percent daily values that are meaningless for the people who actually buy electrolyte supplements. Once you know what to look for, the tricks become obvious.
Here's how to read any electrolyte label in under 30 seconds.
Nutrition Facts vs Supplement Facts — Why It Matters
The FDA classifies electrolyte products as either foods or dietary supplements, and the labeling rules are different for each.[1]
Nutrition Facts labels appear on products classified as foods or beverages — Liquid IV, DripDrop, Gatorade. These must disclose all macronutrients (calories, total carbs, sugars, protein) and list sodium and potassium with both milligrams and percent daily value. The rules here are relatively transparent.
Supplement Facts labels appear on products classified as dietary supplements — most powder and capsule electrolytes. These follow different rules under 21 CFR 101.36.[2] The requirements for disclosing individual mineral amounts differ, so always look for the actual milligram values for sodium, potassium, and magnesium.
A product can contain the exact same ingredients and be classified either way. The brand chooses. And that choice affects what they're required to tell you.
The Serving Size Trick
Serving sizes vary wildly across electrolyte products, and they're not standardized by the FDA for this category. Some examples from actual products:
- One stick pack (6g) — LMNT, Drip Drop
- One scoop (5.4g) — Hydrate Pro, Redmond Re-Lyte
- One tablet — Nuun
- Two capsules — various capsule brands
- One packet mixed in 16oz water — Liquid IV
A product that says "500mg sodium per serving" where one serving is two scoops is not more generous than a product with "500mg sodium per serving" where one serving is one scoop — it just uses twice as much product. Always check what constitutes a "serving" before comparing numbers.
Better yet, skip the per-serving comparison entirely and calculate cost per gram of sodium. That normalizes everything.
Sodium — Why %DV Is Misleading for Electrolyte Buyers
The FDA daily value for sodium is 2,300mg.[3] That's the recommended upper limit for the general population — sedentary adults eating a standard American diet. When an electrolyte product shows 1,000mg sodium as "43% DV," it looks like a massive amount.
But consider who actually buys electrolyte supplements:
- Athletes losing 500-2,000mg sodium per hour through sweat
- Keto dieters who need 3,000-5,000mg sodium daily
- POTS patients who need 3,000-10,000mg sodium daily
- Fasters consuming zero dietary sodium during fasting windows
For these groups, 43% DV isn't alarming — it's one dose out of several needed per day. The %DV was designed for people who don't need electrolyte supplements. Ignore it. Look at the raw milligram number.
Mineral Forms — What They Don't Tell You
Not all forms of a mineral are equally absorbed by your body. This matters most for magnesium, less for sodium and potassium.
Magnesium bioavailability varies dramatically by form. Firoz and Graber (2001) tested commercial magnesium preparations and found that magnesium oxide — the cheapest and most common form — has roughly 4% bioavailability.[4] Magnesium citrate and magnesium chloride were significantly better absorbed. Magnesium glycinate (also called bisglycinate) is generally regarded as one of the most bioavailable forms, though head-to-head comparisons with citrate are limited.
| Magnesium Form | Relative Bioavailability | Notes |
|---|---|---|
| Magnesium glycinate | High | Well-tolerated, less laxative effect |
| Magnesium citrate | High | Good absorption, can have mild laxative effect |
| Magnesium malate | Moderate-High | Often used in sports supplements |
| Magnesium chloride | Moderate-High | Good absorption from solution |
| Magnesium oxide | Low (~4%) | Cheapest form, mostly passes through unabsorbed |
Bioavailability data from Firoz & Graber 2001.[4] Relative rankings are approximate; individual absorption varies.
Most electrolyte supplements contain only 40-60mg magnesium per serving — a small fraction of the 310-420mg daily requirement.[5] At these low doses, form matters less than it would in a dedicated magnesium supplement. But if you're comparing two otherwise similar products, the one using magnesium glycinate or citrate is giving you more usable magnesium than the one using oxide.
Sodium form matters less. Sodium chloride (table salt), sodium citrate, and sodium bicarbonate are all well-absorbed. The differences are taste and gastric tolerance. Sodium bicarbonate can cause bloating. Sodium citrate tends to taste less salty. Most electrolyte products use sodium chloride, sometimes blended with sodium citrate.
Potassium form also matters less for absorption. Potassium chloride and potassium citrate are both well-absorbed. Potassium citrate may have additional benefits for kidney stone prevention, but for basic electrolyte supplementation, either form works.
Sugar and Sweeteners
Three of the 17 brands in our database contain sugar: Liquid IV, DripDrop (original formula), and Gatorade. Sugar adds calories (typically 35-45 per serving) and will break a fast. If fasting compatibility matters to you, check the total sugar and total carbohydrate lines. Both should be zero.
Sugar-free products use stevia, sucralose, monk fruit, or a combination. Stevia is the most common in the high-sodium electrolyte category. The sweetener choice is mostly a taste preference — research doesn't show meaningful metabolic differences between them for most people, with the possible exception of sucralose in obese non-habitual users.[6]
The Three Numbers That Actually Matter
After you know the tricks, comparing electrolyte products gets simple. You need three numbers:
1. Milligrams of sodium per serving. Not percent daily value. The raw sodium number in milligrams. This is the primary functional ingredient in any electrolyte supplement.
2. Price per serving. Calculate this yourself — divide the product price by the number of servings in the container. Marketing often hides this behind per-pack or per-container pricing.
3. Price per gram of sodium. Divide price per serving by grams of sodium per serving (mg ÷ 1,000). This is the only number that lets you fairly compare a 300mg sodium tablet at $0.58 against a 1,000mg sodium powder at $1.50. In that example: the tablet costs $1.93 per gram of sodium vs $1.50 for the powder. The "cheaper" product is actually 29% more expensive per unit of what you're buying.
We've already done this math for 17 brands. You can see the full comparison sorted by any metric.
References
- U.S. Food and Drug Administration. "21 CFR 101.9 — Nutrition labeling of food." Code of Federal Regulations. eCFR
- U.S. Food and Drug Administration. "21 CFR 101.36 — Nutrition labeling of dietary supplements." Code of Federal Regulations. eCFR
- U.S. Food and Drug Administration. "Daily Value on the New Nutrition and Supplement Facts Labels." Updated February 2022. FDA.gov
- Firoz M, Graber M. "Bioavailability of US commercial magnesium preparations." Magnesium Research, 2001;14(4):257-262. PubMed
- National Institutes of Health, Office of Dietary Supplements. "Magnesium — Fact Sheet for Health Professionals." Updated June 2024. NIH ODS
- Pepino MY, Tiemann CD, Patterson BW, Wice BM, Klein S. "Sucralose affects glycemic and hormonal responses to an oral glucose load." Diabetes Care, 2013;36(9):2530-2535. PubMed