Reading labels

How do you read an electrolyte label?

The front of the pack rarely tells you what you are buying. The back panel does. Five checks, about a minute, and they work on any tub or sachet, ours included.

Rawstone Learn · general education, not medical advice

Electrolytes are minerals your body loses in sweat, mainly sodium, plus potassium and magnesium. They help your body hold on to the water you drink. Every tub and sachet in the category claims to replace them. The labels, though, vary wildly, and the front of the pack rarely tells you what you are buying. The back panel does. Here are the five checks we run on any electrolyte product, ours included. They take about a minute in the aisle or on a product page.

Check one: sodium per serve

Sodium is the electrolyte you lose most in sweat, and it is the main signal that tells your body to keep fluid rather than pass it straight through. Research on fluid retention backs this up. A 2021 review in the journal Nutrients found the electrolyte content of a drink, mostly its sodium, mattered more for holding fluid than anything else in it. Below roughly 500mg of sodium per litre the effect is weak. The best-supported range sits around 900 to 1,400mg per litre.

Here is the felt version. If you have ever drunk a "hydration" drink, felt no different, and gone back to plain water, a token sodium dose is the likely reason.

On the panel: find the nutrition table and run your finger down the per-serve column to sodium. Ignore the per-100g column, because nobody drinks 100g of powder. Serves in this category run anywhere from about 100mg of sodium to over 1,000mg. That is a tenfold difference between products that sit on the same shelf. Also glance at the serve size itself. A big sodium number achieved with a two-scoop serve means the tub holds half the serves you think it does.

To be fair to the lighter products, not everyone needs a heavy dose. If you eat plenty of salt and sweat lightly, a small top-up may be all you want. The point of the check is knowing which one you are holding. If you want the full science, we have written up whether 1000mg of sodium is too much separately.

Check two: how much sugar is in it

A surprising share of hydration products are mostly sugar. That is not a scandal by itself. Sugar is cheap, it tastes good, and a little glucose can help the gut take up fluid, which is why medical rehydration formulas include some. The problem is when a product sold on its minerals is really a soft drink with a pinch of salt, and the label lets you catch it.

On the panel: two places. First, the ingredient list. By law, ingredients are listed by weight, biggest first. If the first ingredient is sucrose, glucose, dextrose or fructose, you are buying sugar with minerals added. Second, the nutrition table. Look at the "sugars" row per serve. It is common to find sticks carrying 10g or more of sugar next to a modest sodium number.

One more word to know: maltodextrin. It is a cheap processed starch used to bulk out powders. Your body treats it much like sugar, but it does not have to appear in the sugars row, so a panel can read "low sugar" while the first ingredient is maltodextrin. If you are keto, fasting or just avoiding sugar, scan the ingredient list for it by name.

Check three: which sweetener, and which grade

If the powder is sugar free, something else is making it sweet, and this is where labels get genuinely unhelpful. Most sugar-free electrolyte powders are sweetened with stevia, an extract from a South American plant. Stevia is not one single thing. The common cheap grade, called Reb A, is what leaves that bitter, liquorice-like aftertaste many people blame on the whole category. A different grade from the same plant, called Reb M, tastes clean. It costs a lot more, which is why most brands do not use it. Monk fruit is the other one you will see. It is a small Asian fruit whose extract is intensely sweet with no bitter finish, and it often gets blended with stevia.

Here is the catch. Australian labels usually just say "sweetener (steviol glycosides)" or the additive number 960. Steviol glycosides is simply the chemistry name for the sweet compounds in stevia, and it covers Reb A and Reb M alike. The grade is almost never printed. So you have two options. Ask the brand which grade they use, or run the taste test: a bitter finish that hangs around after you swallow usually means the cheap grade.

Artificial sweeteners are the third path. Sucralose (number 955) and acesulfame K (950) are approved by food regulators and are considered safe at normal intakes. Plenty of people still prefer to skip them, and that is a fair preference. The check is simply knowing which of the three paths your powder takes. We have a longer piece on monk fruit versus stevia if you want the detail.

Check four: the form of magnesium, and of potassium

"Magnesium 75mg" on two labels can behave very differently, because magnesium is never in a powder on its own. It is always bound to a partner compound, and the partner decides how much your body absorbs. The two forms you will see most are magnesium oxide and magnesium citrate. Oxide is dense and cheap, which makes label numbers easy to hit, but it barely dissolves in water and your gut takes in only a small fraction of it. Citrate dissolves fully and absorbs well, so more of the number on the label actually reaches you. Oxide is not dangerous, and it is a reasonable choice in a tablet. In a drink it mostly settles as grit.

Potassium has a version of the same story, and here it is about taste. Potassium chloride is the cheap form and it carries a metallic edge you can taste. Potassium citrate costs more and tastes clean.

On the panel: the ingredient list has to name the compound. Look for the word after "magnesium" and after "potassium". Citrate is the answer you want to see in a drink powder. If the marketing shouts about magnesium but the ingredient list says oxide, the brand chose the label number over your absorption. The full comparison is in our piece on magnesium citrate versus oxide.

Check five: is every batch tested, and can you see the result

Minerals come from mines, salt lakes and evaporation ponds, so every batch of raw material is slightly different, and mineral salts can carry traces of heavy metals like lead and arsenic. Good makers manage this by testing. The document that proves it is called a certificate of analysis. In plain words, that is a one-page report from a testing laboratory listing what was actually measured in a specific batch: the mineral amounts, and the contaminant levels. "Independent" means the lab is not owned by the maker.

Two questions separate a real testing habit from a marketing line. Is every batch tested, or was one sample tested once, years ago? And can you, the buyer, actually see the report for the batch in your hand?

On the panel: find the batch number, usually stamped on the base or shoulder of the tub. Then look for a way to check that batch, such as a QR code or a web address for lab results. If there is nothing, email the brand and ask for the certificate for your batch number. A maker who tests properly can usually send it within a day.

One thing worth knowing before you read your first certificate: every salt-based mineral product on earth will show trace heavy-metal numbers, because they occur naturally in the source. That alone is not alarming. What matters is where the number sits against the food-standards limit. An honest report shows you both, so you can see the margin for yourself.

Where we stand on our own five checks

We should be upfront: we sell in this category. Rawstone is a sugar-free electrolyte hydration powder launching on Amazon Australia in November 2026, so it is fair to score us on the same test. Per serve it carries 1,000mg of sodium, zero sugar and no maltodextrin. It is sweetened with monk fruit and Reb M rather than the cheap Reb A grade. The magnesium is citrate, at 75mg, which makes it a source of magnesium, and the 250mg of potassium is citrate too. Every production batch will go to an independent laboratory, and we will publish each certificate on this site from batch one, with every number shown next to the food-standards limit. One honest caveat: this is a deliberately high-sodium formula for people who genuinely need the salt. If you want something sweet and mild, a mainstream sachet will suit you better.

This article is general education about food labels and nutrition, not medical or dietary advice. If you have a health condition, or you have been told to watch your sodium, talk to your doctor about your intake.