A Certificate of Analysis is the single document that proves a batch is what the label says it is. Most people never see one, and most companies would rather nobody asked. Here’s how to actually read one.
What a CoA is, and isn’t
A Certificate of Analysis is a record of measured values from QC testing, compared against the specification for that product. It’s a snapshot of one specific batch, not a generic claim about a product line.
Every batch we release has its own CoA, identified by batch number, manufacturing date, and expiry date. Two laboratories clear it first: our own internal lab, and one independent accredited third-party lab. Email the batch number printed near the expiry date to info@pharmscale.com and we send the independent lab’s certificate for that exact batch, usually within a few hours.
The anatomy of a proper CoA
Header section, identity
- Product name, matches the label on the bottle
- Batch / lot number, this is the unique key for traceability
- Manufacturing date and expiry / best-before date
- Quantity manufactured, the size of the batch this certificate covers
- Manufacturer name and registration, ours: Pharm Scale d.o.o., Srebrenik, FDA Reg. 14287957814
Specification table, the meat
This is the part worth reading. Each row has three columns:
- Parameter, what was tested (e.g., “Vitamin D3 assay”)
- Specification, what the result should be (e.g., “≥ 90% of label claim”)
- Result, what was actually measured (e.g., “98.2%”)
The 8 lines you should always check
1. Identity test result
Method: HPLC, FTIR, or similar. The result should explicitly confirm the active is what the label says. “Conforms” is acceptable; “passes” is not specific enough, ask what was tested.
2. Active assay result
Should be within ±10% of label claim for most actives. Some thermolabile vitamins (B1, C) need a higher overage during manufacturing because they degrade over shelf life.
3. Disintegration / dissolution time
For solid dose forms only. Capsules should disintegrate in <30 minutes in simulated gastric fluid. If it’s longer, the active won’t release on time.
4. Microbiological, total aerobic count
Look for “< X CFU/g” against the spec. CFU = Colony-Forming Units. Different product types have different limits (botanical ingredients are allowed more than synthetic vitamins).
5. Microbiological, pathogens
E. coli, Salmonella, S. aureus, Pseudomonas. Should ALL read “absent in 1g (or 25g for high-water-activity foods)”. Anything else is a fail.
6. Heavy metals, lead, cadmium, mercury, arsenic
Look for the actual measured value vs the spec, not just “compliant”. A good CoA shows: “Lead: 0.05 mg/kg (spec: < 0.1 mg/kg)”. A poor one says only “compliant”. Our own internal ceiling is one fifth of the EU limit, so the measured value should sit well under the legal figure.
7. Moisture content / water activity
For powders, gummies, and uncoated tablets, this matters for shelf life. Should be within product-specific limits (typically < 5% for powders).
8. Visual / organoleptic
Color, odor, appearance match the reference standard. Sounds soft, it isn’t. Visible discoloration in a finished product is a degradation signal.
Red flags to watch for
- “Compliant” without measured values, the actual numbers weren’t shared, ask why
- Missing test parameters, if nobody is testing for heavy metals on a botanical product, there is a problem
- “Estimated shelf life” without stability data, the shelf life hasn’t actually been tested
- The same CoA issued against multiple batches, major audit failure
- Active assay at <90% of label claim, either underdosed or degraded
- A certificate signed only by the company that made the product, with no accredited third-party lab anywhere on it
What to do with the CoA
If you bought the product
- Match the batch. The number on the certificate has to match the one printed near the expiry date on your bottle. If it doesn’t, you’re reading a different batch.
- Read the assay row. It is the only proof that the milligrams on the label are the milligrams in the capsule.
- Keep it if you are tracking a reaction or a complaint. The CoA tells you whether the product was within spec when it left the facility.
If you stock the product
- Request it per batch. Retailers, especially Amazon, Walmart and the large EU pharmacy chains, will ask for a CoA before listing, and a certificate for last year’s batch does not cover this year’s stock.
- File it. Keep it for the entire shelf life of the batch + 1 year. That is the rule we hold ourselves to under FDA 21 CFR Part 111 and EU good practice.
- Use it. If a customer raises a problem with a specific batch, the CoA is the first document to pull, before anyone talks about a recall.