The manufacturing rules a supplement is actually held to

A different rulebook, not a missing one

A common assumption about supplements is that nobody checks how they are made. That is not what the regulations say. There is a full manufacturing rulebook for supplements, and it runs to dozens of sections.

It is a different rulebook from the one that governs drugs, with different tests and different burdens. Neither is a subset of the other, and the differences are where the useful information sits.

Its reach is broad. The rule applies to anyone who manufactures, packages, labels or holds a supplement, including one made by you but packaged or labeled by someone else, and one imported or offered for import.

It carves out only a narrow slice. Holding requirements do not apply at a retail establishment holding product for direct retail sale, and the rule says a retail establishment "does not include a warehouse or other storage facility for a retailer."

What the word quality is defined to mean here

The regulation defines its own central term, and the definition is worth reading closely because it sets the ceiling on everything else.

Quality means the supplement "consistently meets the established specifications for identity, purity, strength, and composition, and limits on contaminants." It adds that the product must have been made, packaged, labeled and held under conditions that prevent adulteration.

Notice what is not in there. Nothing about whether the ingredient works, whether the amount is useful, or whether a claim on the carton is supported.

The specifications are also the maker's own. The rule requires a manufacturer to establish them, so meeting specification means meeting a target that the manufacturer set.

The one test with no way around it

The strongest requirement in the whole part concerns identity, and it applies before anything is made.

Before using a component, a manufacturer must "Conduct at least one appropriate test or examination to verify the identity of any component that is a dietary ingredient." A supplier's paperwork does not satisfy it.

There is exactly one way out, and it goes through the agency. A manufacturer may petition for an exemption, and the petition has to set out a scientific rationale with supporting data for alternative testing.

The standard that alternative has to meet is written into the sentence. It must show "no material diminution of assurance, compared to the assurance provided by 100 percent identity testing." Where a petition is granted, the testing then happens on terms the agency specifies.

When a certificate of analysis is allowed to stand in

For components that are not dietary ingredients, a supplier certificate can be relied on. The permission comes with five conditions, and they are the part worth knowing.

The supplier has to be qualified first, "by establishing the reliability of the supplier's certificate of analysis through confirmation of the results of the supplier's tests or examinations." So a certificate is trusted only after somebody independently reproduced what it claims.

The certificate itself must carry the method used, the limits of the test, and the actual results. A number with no method behind it does not meet the description.

Three more conditions follow. The manufacturer keeps documentation of how the supplier was qualified, periodically re-confirms the certificate, and has quality control personnel review and approve the basis for that qualification.

The finished-batch test that is weaker than it sounds

This is the provision that most changes what a supplement label means, and it is easy to read past.

Finished-product verification does not have to happen on every batch. The rule applies it to "a subset of finished dietary supplement batches that you identify through a sound statistical sampling plan (or for every finished batch)."

Nor is every specification tested. The manufacturer selects one or more specifications for identity, purity, strength, composition and contamination limits, which if tested would verify that the process is producing product that meets all product specifications.

A further provision lets specific specifications be exempted from that verification entirely. The exemption applies where the selected tests cannot verify the specification and "there is no scientifically valid method for testing or examining such exempted product specification at the finished batch stage."

What is kept, and for how long

The retention rules are the most checkable thing here, because they create a physical object that outlives the sale.

Reserve samples are mandatory. A manufacturer must collect and hold reserve samples of each lot of packaged and labeled supplements that it distributes.

The holding period is specific. Samples are retained "for 1 year past the shelf life date (if shelf life dating is used), or for 2 years from the date of distribution of the last batch" associated with that sample.

The quantity is specified too. A reserve sample must consist of "at least twice the quantity necessary for all tests or examinations to determine whether or not the dietary supplement meets product specifications." That is what makes a later investigation possible.

What counts as a complaint

The rule defines a product complaint far more widely than a customer service queue usually does.

It is "any communication that contains any allegation, written, electronic, or oral, expressing concern, for any reason, with the quality of a dietary supplement, that could be related to current good manufacturing practice."

Its own list of examples includes foul odor, off taste, illness or injury, color variation, under-filled containers, foreign material, improper packaging and mislabeling.

The list ends somewhere unexpected. It includes supplements that are superpotent or subpotent, that contain the wrong ingredient, or that "contain a drug or other contaminant." A supplement containing a drug is, in this rulebook, a manufacturing complaint.

What this does and does not settle for a peptide buyer

Two things follow, and they point in opposite directions.

Where a product is genuinely sold as a supplement, there is a real rulebook behind it, with identity testing before use, reserve samples, records and inspection access. That is more than the usual shorthand about supplements suggests.

But the rulebook is about consistency with the maker's own specifications. It never asks whether the ingredient does anything, and finished-batch verification can lawfully run on a sampled subset rather than on every batch.

And whether a given peptide may lawfully be sold as a supplement at all is a separate question, with its own answer elsewhere on this site. The category question comes first, and this rulebook only applies to whoever is genuinely inside it.

Sources

Each document below is named as it names itself, with the date printed on that document rather than the day it was read.

1. Title 21 Code of Federal Regulations section 111.75, What must you do to determine whether specifications are met — identity testing of a dietary ingredient before use and the exemption petition at (a)(1), the five conditions for relying on a supplier certificate of analysis at (a)(2)(ii), finished-batch verification of a statistically sampled subset at (c), and the specification exemption at (d) — Electronic Code of Federal Regulations, Office of the Federal Register, May 2008
2. Title 21 Code of Federal Regulations section 111.70, What specifications must you establish — component identity specifications, in-process specifications, label and packaging specifications, and product specifications for identity, purity, strength and composition — Electronic Code of Federal Regulations, Office of the Federal Register, June 2007
3. Title 21 Code of Federal Regulations section 111.83, What are the requirements for reserve samples — the container-closure system, batch identification, retention periods, and the requirement that a sample be at least twice the quantity needed for all tests — Electronic Code of Federal Regulations, Office of the Federal Register, June 2007
4. Title 21 Code of Federal Regulations section 111.3, What definitions apply to this part — the definitions of quality, of batch, of component, and of product complaint, including a supplement that is superpotent or subpotent, contains the wrong ingredient, or contains a drug or other contaminant — Electronic Code of Federal Regulations, Office of the Federal Register, June 2007
5. Title 21 Code of Federal Regulations section 111.1, Who is subject to this part — coverage of manufacturing, packaging, labeling and holding, product packaged or labeled by another person, imported product, and the narrow retail establishment carve-out — Electronic Code of Federal Regulations, Office of the Federal Register, June 2007