You started using an electrolyte powder to hydrate better, and maybe you picked one with magnesium because everyone online swears by it. But something is off. Your stomach feels loose an hour later, or you're making an extra trip to the bathroom, or you just don't notice much at all. Before you blame yourself, look at the label. The magnesium in your electrolyte powder is not one single thing, and the form a brand chooses quietly decides whether that magnesium helps you or just passes through.
The magnesium in your electrolyte powder isn't one ingredient
"Magnesium" on a supplement facts panel is shorthand. What actually matters is the compound it's bound to, because that pairing determines how much your body can absorb and how your gut handles it. The common forms you'll see are magnesium oxide, magnesium citrate, and magnesium bisglycinate (also written as magnesium glycinate). They are not interchangeable, and the cheapest one to manufacture is usually the one that serves you least.
This is the detail most hydration brands skip. They'll print a big milligram number on the front of the pouch without telling you what portion of it your body can actually use. A large dose of a poorly absorbed form can look impressive and deliver very little.
Why cheap magnesium can send you to the bathroom
Magnesium oxide is the workhorse of the low-cost supplement world because it packs a lot of elemental magnesium into a small amount of powder. The catch is absorption. A 2021 systematic review of magnesium bioavailability found that fractional absorption of magnesium oxide sat around 4 percent, and concluded that inorganic forms tend to be less bioavailable than organic ones (Blancquaert et al., Nutrients, 2021). Most of what you swallow keeps going.
Magnesium citrate is better absorbed than oxide, but it carries a well-known side effect: it draws water into the intestine by osmosis. That's exactly why citrate is sold on its own as a laxative. In a drink you're reaching for to hold onto fluid, an ingredient whose job is to pull water into your bowel is working against the whole point of the exercise, and for sensitive stomachs it means urgency you didn't sign up for.
None of this makes magnesium bad. It makes the form the thing to check.
What magnesium actually does — and doesn't do — for hydration
Here's the part most front labels leave out: magnesium is not the reason an electrolyte drink hydrates you. Fluid retention is driven mostly by sodium, the main electrolyte your body uses to hold onto the water you drink. The landmark Beverage Hydration Index work showed that drinks with more sodium were retained noticeably better than plain water (Maughan et al., Am J Clin Nutr, 2016). If a powder leans on magnesium as its hydration story, it's telling the wrong story.
What magnesium does earn its place for is different and real. Magnesium is a cofactor in hundreds of enzymatic reactions, and magnesium supports normal neuromuscular function. Alongside sodium, potassium, and calcium, electrolytes support normal nerve signaling and muscle contraction. So the framing is simple: sodium handles the fluid; magnesium is a genuinely useful passenger — as long as it's a form your body can use without discomfort.
How burbo handles its magnesium
burbo uses 100 mg of magnesium as magnesium bisglycinate — 24% of the Daily Value, which makes each stick an excellent source of magnesium. Bisglycinate is magnesium bound to the amino acid glycine, an organic form that's well absorbed and notably gentle on the stomach, without the osmotic pull that makes citrate a bathroom liability. It's the more expensive form to use, and it's the one we chose on purpose.
The magnesium sits inside a formula built the right way around: 327 mg of sodium per stick supports fluid absorption and retention, with 200 mg potassium, 50 mg calcium, and 140.3 mg chloride rounding out the electrolyte profile. Every batch is third-party tested for heavy metals, so you know what's in the stick you're mixing. It's sweetened with OnoSweet, a zero-calorie form of Reb M, plus a trace of organic agave for flavor rounding — named plainly because a clean label has nothing to hide.
How much magnesium is the right amount
More is not better with magnesium, and a good formula tells you where it stops. One burbo stick in a full bottle of water covers an ordinary day, a workout, or a flight. In extended heat or a long session, roughly one stick per hour of continued sweating keeps pace. Two sticks a day is comfortably fine; three is the practical ceiling. If you need more sodium beyond that, take it from food rather than stacking more sticks — and always add a full bottle of water with each one, because more sticks should mean more fluid, never a stronger, more concentrated drink.
The takeaway
When you compare electrolyte powders, don't stop at the magnesium number on the front. Turn the pouch over and read the form. Oxide is cheap and mostly passes through; citrate is absorbed but can loosen your gut; bisglycinate is the well-absorbed, stomach-friendly choice. Pair the right magnesium with enough sodium to actually retain fluid, and you've got a drink that works with your body instead of against it.
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.