Third-party tested supplements: what a COA and GMP really mean

Third-party tested supplements have been checked by an independent lab, not just the brand, for things like identity, potency, and contaminants. The results are often summarized in a Certificate of Analysis, or COA. GMP certification means the manufacturing facility follows current Good Manufacturing Practices for quality and consistency.

Why does testing matter for supplements?

In the United States, dietary supplements do not need FDA approval before they are sold. Manufacturers are responsible for making sure their products are safe, correctly labeled, and made under current Good Manufacturing Practices. The FDA can inspect facilities and act on problems, but it does not test every product before it reaches a shelf. That puts real weight on how a brand checks its own work.

What is a Certificate of Analysis (COA)?

A Certificate of Analysis is a document from a laboratory that reports test results for a specific batch or lot of a product or ingredient. It lists what was tested, the method used, the acceptable range, and the actual result, usually with a pass or fail for each.

How to read a COA

1. Match the product name and, if possible, the lot number to your bottle.
2. Note the testing lab and whether it is independent of the brand.
3. Compare each result with its specification or acceptable limit.
4. Check the date; a COA should be reasonably recent.

What does GMP certification mean?

GMP stands for Good Manufacturing Practices. For supplements, the FDA's current GMP rules cover how facilities are run: staff training, cleanliness, equipment, record keeping, ingredient identity testing, and quality control for every batch. GMP certification means an outside organization has audited a facility and confirmed it follows those practices.

GMP is about the process, not a single product. It tells you the factory runs to a documented standard. A COA tells you how a particular batch tested. The two together give a fuller picture.

What does third-party tested mean?

"First-party" testing is done by the manufacturer itself. "Third-party" testing is done by an independent lab with no stake in the result. Independent testing adds a layer of accountability. The term is not regulated, so the most useful brands go further than printing it: they let you see the documentation.

Questions to ask any supplement brand

• Can I see a Certificate of Analysis for this product?
• Who performed the testing, and are they independent?
• What was tested: identity, potency, heavy metals, microbes?
• Is the facility GMP certified, and by whom?
• Where is the product manufactured, and where are ingredients sourced?
• How do I contact you if I have a question about a batch?

A brand that answers these questions clearly is giving you something more valuable than a marketing claim.

How Plum handles testing

Plum products are manufactured in the USA using globally sourced ingredients. They are third-party tested and made in GMP-certified facilities. Our manufacturing partner publishes compliance documentation, including Certificates of Analysis and manufacturing certifications.

You can view the Certificate of Analysis (COA) documents at any time, and the same link appears on every product page.

To see how testing fits with the rest of a label, read how to read supplement labels.

Key takeaways

• Supplements are not FDA approved before sale, so testing practices matter.
• A COA reports lab results for a specific batch.
• GMP certification covers how a facility is run.
• Third-party means an independent lab, and documentation beats a printed claim.
• Ask brands to show their testing, not just describe it.

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.