Magnesium glycinate at 2,000 mg per serving is a chelated form, so the elemental number on the panel runs lower than the salt weight. Check that row before you compare prices.
If you want to see this on a real label, the Aged Garlic Extract Gummies 90 Count - 45 Day Supply, Subscribe and Save Available product page carries the full Supplement Facts panel.
Why the magnesium glycinate label and the certificate disagree
It's common to see 2,000 mg on the front of a bottle and 200 mg on the back, and both figures can be accurate. The salt weight includes the glycine carrier. A certificate of analysis lists the assay as a percentage of the finished lot, usually 98 to 101 percent of label claim, which is a different question from how much elemental mineral you swallow.
You can ask for a lot specific certificate by email. Most brands send one within a week.
What the four magnesium glycinate assays actually cover
Read the assay list left to right and you'll see which questions got answered. Identity is a spectrum match, potency is an HPLC figure against the label, and the metals screen is a separate ICP-MS run that most contract labs charge for by the panel.
Microbial testing covers total aerobic count, yeast and mould, and the pathogens a lab routinely screens for. Ask for the two page report, not the one line summary on a product page.
Identity, potency, heavy metals and microbial counts are four separate tests. A panel that lists identity and potency but skips lead and cadmium tells you the powder is the right molecule and says nothing about what else came with it.
Arsenic, cadmium, lead and mercury limits are often set at 10 ppm under California's Proposition 65 for lead, which is a ceiling and not a target. A lot tested at 0.2 ppm lead is a different product from one at 4 ppm even though both pass.
Asking for the batch, not the magnesium glycinate brand
Brand level certificates are marketing. You want the lot number printed on the bottle, the lab that ran it, the date, and which four assays were ordered. If a seller posts a certificate with no lot number it's decoration.
When you buy a 60 count bottle at $25.99 and take two gummies a day, you're buying a 30 day supply at about 87 cents a day, so a certificate request once per batch is cheap insurance. Test results cost the brand between $300 and $1,200 per lot depending on the panel.
Two more points worth stating plainly. A certificate of analysis describes a powder lot, not your specific gummy, so the manufacturing step between them is documented separately. And a passing certificate is not a claim about what magnesium glycinate does in your body, only that the material matched its specification.
I'd rather see a boring scan of a real lab report with a lot number and a date than a badge on a homepage.
Where the store gets this wrong
Ordering two bottles together is the usual pattern here, and the second bottle often arrives from a different production run. That's normal at this volume. It also means the certificate you saved in March may not describe what showed up in June, and the seller knows it.
Bundles tend to hide this. A three pack at a lower per unit price may come from three different lots, and the certificate you were shown covers one of them. Ask which lot shipped before you assume the discount bought the same material.
There is one more wrinkle. A retailer can publish a certificate for a grade of magnesium glycinate it stocks rather than for the lot in the warehouse, and the two documents look identical at a glance. Lot numbers and dates are what separate them.
A 120 count bottle of the same material at $0.31 per serving changes the arithmetic but not the question you should be asking the seller.
That's the part worth your time.
Frequently asked questions
What does a certificate of analysis cover?Show answerHide answer
Whatever assays were ordered. Ask which were run before assuming anything.
Is testing legally required?Show answerHide answer
Verification is voluntary in most of the market, which is why brands differ so much.
What should I ask a brand?Show answerHide answer
Which batch was tested, by which lab, and for which four things.
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.
