Three magnesium glycinate bottles sit on our shelf. Their front labels say 1330 mg, 200 mg and 120 mg — numbers that look like a tenfold difference in strength. Read the Supplement Facts panels and the picture flips: two of the three deliver exactly the same magnesium per capsule. This guide walks through those three real labels and shows which line to trust when the front numbers cannot be compared.
The only line that counts: elemental magnesium
A magnesium capsule contains a magnesium compound — glycinate, citrate, oxide — and the compound weighs far more than the magnesium inside it. Some brands put the compound weight on the front; others put the magnesium itself. The Supplement Facts panel is where every brand must state the actual (elemental) magnesium, and here is what our three panels print:
- Horbäach Magnesium Glycinate 1330 mg — front says 1330 mg per serving; the panel says Magnesium 240 mg — 57% DV, from 1,330 mg of a buffered glycinate blend, per 2-capsule serving.
- Bronson Magnesium Glycinate 200 mg — front says 200 mg per serving; the panel confirms Magnesium 200 mg — 48% DV per 2 capsules. Here the front number already is the elemental one.
- Thorne Magnesium Glycinate 120 mg — Magnesium (as Magnesium Glycinate) 120 mg — 29% DV per single capsule.
So the 1330 on one front and the 200 on another are answers to two different questions — one weighs the compound, the other the mineral. Only the panel line makes them comparable.
The division check: all three point at 420 mg
Divide each dose by its printed %DV and the labels reveal the Daily Value they were calculated from: 240 ÷ 57% ≈ 421, 200 ÷ 48% ≈ 417, 120 ÷ 29% ≈ 414 — all rounding to the FDA's 420 mg Daily Value for magnesium. That base matches the Recommended Dietary Allowance for men 31 and older listed by the NIH's MedlinePlus encyclopedia; the RDA for adult women is 310-320 mg, and pregnancy has its own 350-400 mg range. Same capsule, different share of your own number — which number applies to you is a question for your clinician.
Per capsule, not per front label
Serving sizes differ — 2 capsules, 2 capsules, 1 capsule — so the per-capsule math is where the surprise lives: Horbäach 240 ÷ 2 = 120 mg per capsule, Thorne = 120 mg per capsule, Bronson 200 ÷ 2 = 100 mg per capsule. The bottle shouting 1330 and the bottle stating 120 hand you the identical dose per capsule. Bottle life follows serving size, not count: 250 capsules = 125 servings, 90 capsules = 90 servings, 60 capsules = 30 servings.
What “buffered” means on these labels
Shoppers often search “magnesium glycinate vs oxide” as if a bottle must be one or the other. Two of our three glycinate labels are quietly both: Horbäach's panel parenthesis reads “Magnesium Glycinate Chelate Buffered - Magnesium Bisglycinate Chelate, Magnesium Oxide”, and Bronson's panel discloses the same pairing with an Albion® trademark. On these labels, “buffered” is the word that signals an oxide share in a glycinate product — and the parenthesis after the mineral is the only place it is spelled out. Thorne's panel names glycinate alone. Which form suits you is outside this guide; our point is that the answer sits in the parenthesis, not in the product name.
Shells and printed warnings
The Other Ingredients lines separate the three again: Horbäach uses a gelatin capsule; Bronson and Thorne use vegetarian cellulose-based capsules. Bronson also prints a warning block — do not use while pregnant or nursing, and consult a professional first with any medical condition or medication. And as on every supplement we have covered, the front-label phrasing about absorption carries an asterisk leading to the standard federal small print; we leave that conversation to the bottle and your clinician.
Browse the shelf these labels came from: Magnesium. For the same label-first walkthroughs of other nutrients, see the zinc label guide — elemental math's original home — and the biotin label guide for what five-digit %DV numbers mean.