Certificates, batches and magnesium glycinate

One certificate rarely covers all four magnesium glycinate questions

A certificate of analysis for magnesium glycinate tells you which assays the lab actually ran, and nothing more. Identity, potency, heavy metals and microbial counts are separate tests, and a single-page certificate often documents only one or two. A heavy metals panel alone carries results in mg/kg. That's the whole assurance problem in a sentence.

I learned this the dull way. Years back I asked a supplier for their certificate, got a PDF back the same afternoon, and felt satisfied for about a week. Then I read it properly. The document confirmed the material was magnesium glycinate and nothing else. No lead figure. No microbial plate count. It was genuine paperwork answering a narrower question than the one I thought I'd asked.

Identity testing is the floor, not the ceiling

Identity testing confirms the powder in the drum is what the label says it is. Labs do this with spectroscopy or with a marker compound, and it's the cheapest check available. It rules out substitution. It says nothing about strength.

Potency is the second question, and for a chelated mineral it's more specific than people expect. Magnesium glycinate at 1000 mg of compound delivers roughly 140 mg of elemental magnesium. A certificate that quotes total compound weight without stating the elemental yield hasn't answered the question you're actually asking.

Heavy metals and microbes, the two people skip

Minerals are mined and refined, so they pick up trace metals from the processing chain. A heavy metals panel usually covers lead, cadmium, arsenic and mercury, each with a result in mg/kg against a limit. Common limits sit near 1 mg/kg for lead and 0.5 mg/kg for cadmium. Without those numbers on the page, you're taking the supplier's word on a question nobody tested.

Microbial testing covers total aerobic count, yeast and mould, E. coli and salmonella. A finished powder sitting in a warehouse for 6 months is exactly where a mould problem would show up. Typical acceptance sits under 10,000 cfu/g. Again, it's a separate assay with a separate fee, which is why it's frequently absent.

What I ask a brand now

Three questions, in this order. Which batch was tested, at what lab, and for which of the 4 things. If a supplier can't name the lab, the 1-page certificate is worth very little. If they can name it but won't say what batch, ask again. A certificate from 2 years ago attached to today's shipment proves nothing about what's in the box.

Verification is voluntary across most of this market. That's not a scandal, it's just the structure of supplement regulation in most countries, and it means brands differ enormously in how much testing they commission. Some run all 4 assays every batch. Some run identity once a year.

Where our own answer stops

We commission identity, potency, heavy metals and microbial testing on our magnesium glycinate, and we can tell you which lab ran each panel if you write in. What we won't claim is that testing makes a product effective, because those are separate questions and the second one isn't settled by a lab report.

Testing answers whether the material is what it says on the label and whether it's clean. It doesn't answer whether it does anything for you. Keeping those 2 questions apart is the most useful habit I've picked up in this category.

Three things worth asking before you buy

What does a certificate of analysis cover? Whatever assays were ordered, so ask what was run before you assume anything at all.

Is testing legally required? Verification is voluntary in most of the market, which is the reason brands differ so much here.

What should I ask a brand? What batch was tested, at what lab, and for which of the 4 things.