cGMP: what current good manufacturing practice means when you buy

Which rules apply to which products

cGMP is not one rulebook. FDA has separate good manufacturing practice regulations for food, dietary supplements and drugs, and the one that applies to your product is the one a factory has to meet.

The supplement rule reaches further than many brands expect: packaging, labeling and holding are covered, not just making. If a factory abroad makes your supplements, the supplement company guide covers what the rule means for you as the brand.

What cGMP tells you, and what it does not

The rules are about how a product is made, not only how it tests. FDA's own explanation of drug cGMP is that testing alone is not adequate to ensure quality^[1], because testing looks at a sample of a batch. A certificate of analysis for one batch is useful, but it does not show that the plant controls every batch.

For drugs, the legal stakes are direct: in the regulation's words, failing to follow the rules shall render such drug to be adulterated^[4]. FDA adds that this kind of adulteration does not mean that there is necessarily something wrong with the drug^[1]. It is a finding about the process, which is exactly why a buyer should care about the process and not only the lab result. FDA inspects pharmaceutical manufacturing facilities worldwide^[1], so an overseas drug plant is not outside its reach.

When a factory says it follows cGMP, ask what the statement rests on. It might be the outcome of an FDA inspection, an audit report from a third party, or only the factory's own word. Those are very different levels of evidence, so ask to see the document behind the statement before you order.

Example: comparing two factories' claims

Two capsule factories, both saying they follow cGMP for supplements

What each sent	Factory A	Factory B
Basis for the claim	A third-party audit report against the supplement rule, dated this year, with findings and corrective actions	A logo on its brochure
Batch evidence	A batch record summary and a certificate of analysis for a recent batch of a similar product	A certificate of analysis only
Specifications	Written specifications it would set for your product	Offered after you place the order
Who releases a batch	Named quality staff, with their sign-off on the batch record	Not stated

Illustrative figures, not a quote. Real prices depend on the spec, quantity and factory.

Factory A has shown how it runs; Factory B has only said it does. Ask B for the same documents A sent before choosing it, and consider a factory audit by an auditor you pick. Whatever the factory sends, the contract should still say who writes the specifications and who decides whether a batch ships, the split that contract manufacturing arrangements live or die on.

What to ask about a facility

• Which regulation applies to the product, and which parts of the process does the facility do in house?
• When was the facility last inspected by FDA, and what was the outcome?
• Is there a recent third-party audit report against that regulation, with its findings?
• Is there a batch record summary and certificate of analysis for a recent batch of a similar product?
• Who in the quality team releases a batch, and does their sign-off appear on the batch record?