Supplements aren’t regulated like medicines — so what actually guarantees the label matches the contents? Independent testing. Here’s how it works and what to look for.
In the UK and EU, supplements are regulated as food, not medicines. Manufacturers are legally responsible for making products that are safe and accurately labelled — but there’s no pre-market approval of every batch the way there is for drugs. Independent testing exists to close that trust gap, because surveys have repeatedly found products that under-deliver, over-deliver, or contain unwanted contaminants.
A COA is a lab report for a specific batch. It covers two things you care about: identity and potency (does it contain what the label says, at the stated amount?) and purity (is it free from meaningful levels of heavy metals, microbes and other contaminants?). Ideally that testing is done by an accredited, independent laboratory.
Several independent programmes put a mark on products that pass their checks — for example NSF, Informed Sport (which screens for substances banned in sport, useful for athletes) and USP. Each verifies slightly different things, but all signal that someone other than the brand has looked inside the bottle.
Finally, look for GMP. Making a product in a GMP-certified facility means it’s produced to consistent, controlled quality and hygiene standards — the foundation that testing then verifies. UK manufacturing to these standards is a quiet but meaningful quality signal.
Because supplements are regulated as food, independent testing is your best assurance the label matches the bottle. Look for batch testing or a Certificate of Analysis, GMP manufacturing, and recognised third-party marks.
Manufacturers are legally responsible for safety and accurate labelling, but independent third-party testing provides extra, unbiased verification of potency and purity.
A document from a laboratory confirming a batch's identity, potency and purity, including tests for contaminants such as heavy metals.
Good Manufacturing Practice: a certified standard for making products consistently and hygienically to controlled quality specifications.