Elemental magnesium cost per serving is the only figure that matters
Elemental magnesium cost per serving comes from dividing the pack price by the number of servings, not the count of capsules. A 120 capsule pack at $24 sounds cheap until you notice the label asks for 3 capsules a day, which makes it 40 servings at $0.60 each. A 90 capsule pack at $27 that asks for 1 capsule daily is 90 servings at $0.30. The second pack wins, and the sticker price told you the opposite.
Servings first. Sticker price last.
Why capsule counts mislead you
Capsule size, mineral yield and the form of magnesium all change how many you swallow per day. Magnesium oxide packs a lot of the mineral per gram and sits cheap on the shelf. Magnesium glycinate carries less magnesium per capsule, so a day's worth can run to 2 or 3 capsules. Same milligram target, very different counts.
Compare 2 products by capsule count and you compare nothing at all. The count describes packaging. The serving describes what you take.
Run the arithmetic once
Take the price, divide by servings per pack, and write the result down. Then divide by the servings you take each day to get a monthly cost. A jar of 180 capsules at $30, requiring 3 per day, gives 60 servings at $0.50, and 30 days of use costs about $15. A jar of 60 capsules at $18, requiring 1 per day, gives 60 servings at $0.30, and 30 days costs about $9.
The bigger jar costs more per day in that example. Larger isn't automatically cheaper, and a 90 count can beat a 180 count on cost even before you check the dose.
A counter conversation about value
A regular came in and told me she'd found magnesium at $0.43 per day on a subscription and wanted to know if the larger tub beat it. We did the division together at the counter. Her 300 count tub worked out to $0.71 per day, because the label asked for 4 capsules. She'd been paying 65 percent more and feeling clever about the size.
That's the trap. Volume feels like value.
Check the dose hasn't dropped
Here's the limit on this method. A low per-serving cost only means something if the mineral amount per serving stays steady. Some brands trim the dose when they enlarge the package, and the per-serving figure looks flat while the amount you get falls. Read that line on both labels before you celebrate a cheaper day.
Subscription pricing changes the per-order number and removes the reorder decision, which is its own kind of value. It doesn't change the arithmetic. Price divided by servings, every time.
Keep one number on your phone
Work out the cost per day for whatever you buy now and keep it in a note. Next time you shop, do the same division for the new pack before you reach the till. Two minutes, and the cheapest sticker price stops being your default.
Where the cheap bottle hides its cost
A bargain bottle usually wins on one line and loses on another. It may use a cheaper form that asks for 4 capsules instead of 1, or it may pad the count with a lower mineral yield per serving. Neither is dishonest. Both change the number you actually pay each day.
Read 3 things on any magnesium label before you compare prices. The magnesium per serving, the serving size in capsules, and the total servings in the bottle. With those 3 figures and the price, you can rank any two products in under a minute.
Frequently asked questions
How do I compare two bottles?Show answerHide answer
Divide price by servings, then check the servings per day the label asks for.
Is buying larger always cheaper?Show answerHide answer
Usually, but check the per-serving dose has not quietly dropped.
Does subscription change the price?Show answerHide answer
It reduces the per-order figure and removes the reorder decision.
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.
