You flip over two electrolyte packets and the numbers don't line up. One says 1,000 mg of sodium. One says 200 mg. One brags about "72 trace minerals." One has as much sugar as a sports drink. They all promise the same thing, and none of them tell you which is right for you.
Learning how to read an electrolyte label takes about a minute once you know where to look. Four numbers, one ingredient form, and one ratio — that's the whole test. Here's how to run it.
Start with the serving size, not the front of the box
The front of the package is marketing. The Supplement Facts panel is the product. And the first line of that panel — serving size — quietly determines whether any of the other numbers mean anything.
A stick pack that delivers 500 mg of sodium in 16 oz of water is a very different drink from one delivering 500 mg in 8 oz, even though the label numbers are identical. Concentration is what your gut actually experiences. Before you compare two products, check whether they assume the same amount of water. If they don't, you're comparing nothing.
Also check servings per container. Some powders list a scoop as one serving but suggest two scoops on the directions, which quietly doubles every number you just read.
How to read an electrolyte label: the four numbers that matter
1. Sodium — the one that does the heavy lifting
Sodium is the primary mineral in the fluid outside your cells, and it's the reason electrolyte drinks work at all. Water follows sodium. Drink plain water with no sodium and your blood dilutes slightly, your kidneys read that as "too much fluid," and a good share of what you drank leaves as urine before it does much for you.
Sodium content is also where brands diverge most. Some heavy-sweat formulas push toward 1,000 mg per serving. Everyday formulas often sit in the low hundreds. Neither is wrong — they're built for different days. What matters is whether the number matches your sweat losses. If you're not producing visible salt on your skin or training hard in heat, a very high-sodium drink isn't doing extra work; it's mostly just making you thirstier.
2. Potassium — the inside-the-cell partner
Potassium is the dominant mineral inside your cells, and it works with sodium to keep fluid distributed correctly across cell membranes. Most electrolyte powders include it in modest amounts, and that's appropriate — you lose far less potassium in sweat than sodium, and most of your daily potassium should come from food anyway.
Be skeptical of a label where potassium is a rounding error, and equally skeptical of one where it dwarfs sodium. Neither pattern reflects what you actually lose.
3. Magnesium — read the form, not just the milligrams
This is the line most people skim, and it's where labels hide the biggest quality difference. Two products can both say "60 mg magnesium" and behave completely differently in your body, because the form determines how much you absorb.
- Magnesium glycinate (also written bisglycinate) — well tolerated, gentle on the gut, a sign the formulator cared.
- Magnesium citrate — absorbs well; in larger doses it has a laxative effect, which is why it shows up in some "cleanse" products.
- Magnesium malate — another well-tolerated option.
- Magnesium oxide — cheap, poorly absorbed, and the most likely to cause digestive complaints. Its presence usually tells you the formula was built to a price.
On a well-labeled product, the form is printed in parentheses after the mineral name, or listed in the ingredients line. If a label just says "magnesium" with no form disclosed, that's information too.
For the record, this is a test we're glad to be measured against: burbo uses magnesium bisglycinate at 100 mg per stick, which is 24% of the Daily Value. We give you the criterion, not just the answer, so you can run it on anyone — us included.
4. Sugar and total carbohydrate
Sugar isn't automatically the villain here. Glucose and sodium share a transporter in the small intestine, so a small amount of carbohydrate can genuinely speed fluid uptake — that mechanism is the basis of clinical oral rehydration solutions.
But that effect is dose-dependent and it saturates fast. Beyond a modest amount, extra sugar stops helping absorption and starts slowing gastric emptying, which is the sloshy, heavy feeling some sports drinks give you mid-run. Roughly: if you're going hard for over 90 minutes, some carbohydrate is useful fuel. For a hot afternoon, a flight, or a Tuesday, 20+ grams of added sugar is a soda with a mineral garnish.
The quirk nobody explains: a missing sugar line
Here's something that trips up even careful label-readers, and almost no one in this category bothers to explain it.
Nutrition Facts panels — the ones on food — print "0g" all over the place. Supplement Facts panels aren't allowed to. FDA's rule for dietary supplements (21 CFR 101.36) says any nutrient present in an amount that rounds to zero shall not be declared. Not "may be omitted" — shall not. So a supplement powder whose sugar rounds down to zero has to leave the line off the panel entirely rather than printing a reassuring zero.
Which means the absence of a sugar line on a Supplement Facts panel is itself information, not evasion. If a supplement panel shows you a sugar number, there is real sugar in there worth accounting for. If there's no line at all, the rounding took care of it.
Same logic applies to calories and total carbohydrate on a supplement panel. This is the single most common reason people email a brand asking "why doesn't your label say how much sugar is in this" — and the answer is usually that the law wouldn't let them.
The ratio tells you what the product is really for
Once you have the four numbers, look at their relationship rather than their size. A formula heavy on sodium with minimal sugar is built for salty sweaters and heat. A formula with high sugar and low sodium is built for taste. A balanced, moderate profile is built for daily use.
None of those is inherently better. But a label that's high in everything usually isn't "more complete" — it's often just trying to win a spec sheet comparison. At burbo, we've deliberately kept the sodium in a moderate range — 327 mg per stick — for exactly this reason: over-salting a drink you sip all day doesn't hydrate you faster, it just makes the drink harder to finish.
Then read the bottom of the panel
Below the minerals sits the "other ingredients" line, and it's where the actual differences in product philosophy live. Scan for:
- Sweeteners. Sucralose, acesulfame potassium, stevia, monk fruit, or Reb M — all legal, all different in taste and tolerance. Reb M is the newer one worth understanding: it's the stevia-leaf molecule that tastes closest to sugar, and it's now typically produced by fermentation rather than leaf extraction, which means a Reb M product isn't necessarily a stevia product. Just know which one you're drinking. Ours is Reb M, paired with a trace of organic agave for flavor — both listed in the other ingredients, if you're wondering.
- Artificial colors. A hydration powder has no functional reason to be neon.
- Fillers and anticaking agents. Fine in small amounts, but if they appear before the active minerals, the scoop is mostly not what you're paying for.
- Proprietary blends. If a "trace mineral complex" doesn't break out individual amounts, you can't evaluate it. Treat it as decoration.
Match the label to the day you're actually having
The right label isn't universal — it's situational:
- Everyday, indoors, moderate activity: moderate sodium, low or no added sugar, well-absorbed magnesium form.
- Long sessions in heat, or visible salt crust on your skin: higher sodium, and carbohydrate if you're going past 90 minutes.
- Travel, dry air, or recovering from a rough night: moderate sodium, low sugar, plenty of plain water alongside it.
The 60-second label test
Next time you're deciding between two products, run this in order:
- Serving size and water volume — are they even comparable?
- Sodium — does it match your actual sweat losses?
- Magnesium form — glycinate, citrate, or malate rather than oxide?
- Added sugar — under a few grams unless you need the fuel. Remember that on a supplement panel, no line at all means it rounded to zero.
- Other ingredients — anything you wouldn't want daily?
That's it. The brand that wins on the front of the box often loses on the back, and once you can read the panel, the marketing stops mattering. Pick the label that fits the day you're having — including ours, if it does.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. How this article was researched and written: our editorial standards.