If you buy supplements, you have probably seen phrases such as “third-party tested”, “lab tested" or “independently tested” on product pages and packaging.
They sound reassuring, but what do they actually mean?
Not all supplement testing is the same. A product may be manufactured to a specification, tested by the manufacturer, or independently analysed by an external laboratory. Even when a supplement is described as third-party tested, what was tested, which batch was tested and which laboratory performed the analysis all matter.
Here’s what to look for.
What Is Third-Party Testing?
Third-party testing means a supplement is sent to a laboratory that is independent of the company manufacturing or selling the product for analysis.
The purpose is simple: rather than relying solely on information supplied by the manufacturer, an independent laboratory can provide additional verification of what is actually in the product.
Depending on the supplement and the tests requested, a laboratory may analyse:
- Identity - is the ingredient actually what the label says it is?
- Assay or potency - how much of the active ingredient is present?
- Heavy metals - such as lead, cadmium, mercury and arsenic
- Microbiology - testing for potentially harmful microorganisms
Why Does Independent Testing Matter?
In the UK, food supplements are regulated as foods, and businesses selling them are responsible for ensuring their products are safe and comply with applicable food law.
Independent testing can add another layer of quality control providing verification and proof of quality.
What Does ISO/IEC 17025 Mean?
Another phrase worth understanding is ISO/IEC 17025.
ISO/IEC 17025 is an internationally recognised standard for the competence of testing and calibration laboratories. In the UK, UKAS accredits testing laboratories against this standard.
Accreditation considers factors including:
- the competence and training of laboratory staff
- the suitability and maintenance of equipment
- appropriate and valid testing methods
- sampling and handling procedures
- measurement traceability
- quality assurance
- accurate recording and reporting of results
Third-Party Tested vs Manufacturer Tested
These terms can easily be confused.
Manufacturer testing means testing is performed by the manufacturer itself or as part of its internal quality-control process.
Third-party testing means the analysis is performed by an independent external laboratory.
Internal quality control can still be an important part of manufacturing. The difference is independence.
A strong quality-control process can therefore include both: controls and testing during manufacturing, followed by independent testing of the finished supplement.
What Is a Certificate of Analysis?
A Certificate of Analysis (CoA) is a document showing the results of laboratory analysis for a particular sample or batch.
- Depending on the testing performed, a CoA might show:
- the product or sample tested
- batch or lot information
- the testing date
- the analytical method
- the tests performed
- the measured results
- specification or acceptance limits
- whether the sample passed those specifications
A CoA can therefore give consumers considerably more information than simply seeing “third-party tested” on a label.
Is Testing Every Batch Better?
Testing one product sample can tell you about that sample.
It does not automatically prove that every future production batch will produce identical results.
This is why batch-level testing provides greater transparency. When new batches are independently tested, the results relate more closely to the product currently being sold.
If a company publishes testing information, look for a batch or lot number and compare it with the number printed on your product.
That allows you to see whether the test results actually correspond to the supplement you have purchased.
What Should You Look For When Buying a Third-Party Tested Supplement?
Rather than stopping at the words “third-party tested”, ask a few more questions:
What has actually been tested?
Look for details such as identity, active ingredient content, heavy metals and microbiological testing.
Was the testing independent?
Check whether an external laboratory performed the analysis.
Is the laboratory appropriately accredited?
ISO/IEC 17025 accreditation is an important indicator of laboratory competence.
Can you see the results?
Brands that make relevant testing information or Certificates of Analysis available give consumers the opportunity to verify their claims.
Can the results be linked to a batch?
A batch number makes it possible to connect a laboratory report with a particular production run.
How We Approach Third-Party Testing at Everyday Supplements
At Everyday Supplements, transparency is one of the principles behind how we develop our products.
Our L-Theanine contains 200 mg of L-Theanine per capsule with no fillers or unnecessary additives, and we don't believe customers should simply have to take our word for what's inside.
That is why every batch is independently third-party tested.
Our testing includes checks for:
- L-Theanine identity and assay
- Lead
- Cadmium
- Mercury
- Arsenic
- Aerobic plate count
- Yeast and mould
- Coliforms
- E. coli
- Staphylococcus aureus
- Salmonella
Testing is carried out independently through an ISO/IEC 17025 accredited laboratory, providing an additional level of verification beyond the manufacturing process.
We also make our testing information available so customers can see the evidence behind the product. Because when it comes to supplements, transparency shouldn't just be a marketing claim, you should be able to see the evidence.