VITAMINS & SUPPLEMENTS · GUIDE
Good Manufacturing Practice (cGMP) and What FDA Inspections Cover
What the US good manufacturing practice rule (cGMP, 21 CFR Part 111) requires of supplement makers, what FDA inspections and oversight cover, and what a GMP claim on a label cannot tell you.
Content last updated . This page has not been medically reviewed.
Back to Supplement FormulasThis page describes the US rules as FDA and the federal regulations state them. Other countries are not covered in the sources we read; see supplement regulation by country.
What the rule asks makers to do
The rule is long. These are examples taken from the regulation text, not a full list.| Area | What Part 111 says |
|---|---|
| Who is covered | Anyone who manufactures, packages, labels or holds a dietary supplement, including imported products [1] |
| Retail shelves | Holding requirements do not apply to a retail establishment holding products only for direct sale to individual consumers [1] |
| Ingredient identity | Makers must conduct at least one appropriate test or examination to verify the identity of each component that is a dietary ingredient, unless FDA grants an exemption petition [1] |
| Specifications | Makers must set specifications for identity, purity, strength and composition, and limits on contamination that could adulterate the product [1] |
| Finished batches | For a subset of batches chosen by a sound statistical sampling plan, or for every batch, the maker must verify the finished product meets its specifications [1] |
| Supplier paperwork | For components other than dietary ingredients, a maker may rely on a supplier's certificate of analysis only after qualifying the supplier and re-confirming it periodically [1] |
| Reserve samples | Makers must collect and hold reserve samples of each lot of packaged and labeled product that they distribute [1] |
| Complaints | Quality control must review decisions about whether to investigate a product complaint [1] |
Every multi-ingredient formula has several components, and the rule treats each dietary ingredient as a component to be identity-tested. [1]
What FDA does about it
FDA says its role includes inspecting dietary supplement manufacturing establishments, reviewing new dietary ingredient notifications, investigating complaints, monitoring the marketplace and examining imported products. [2] Facilities that make, pack or hold dietary supplements for US consumption must register with FDA. [2] FDA issues warning letters to companies it finds have violated the laws it enforces. [4]FDA also says its resources for analyzing products are limited, so it focuses first on public health emergencies and products that may have caused injury or illness. [2] It can act against an adulterated or misbranded supplement after it reaches the market. [5]
What is not described in the sources we read
- How often a given facility is inspected, or how many pass: Proper evidence not found. We read FDA's consumer Q&A, its supplement overview pages and the regulation text, and searched PubMed for studies of cGMP inspections and violations. None gave inspection frequency or results.
- What "GMP certified" or "made in a GMP facility" means on a label: not described in the sources we read. FDA warns to be cautious when a product says it is made in an "FDA-approved facility," because FDA does not approve facilities. [3]
- Whether following cGMP means a product works or is safe for you: the rule is about manufacturing quality. It does not review a formula's benefit or its fit with your medicines.
Why it still matters
Authors of a 2025 review note that manufacturers selling in the US are required to comply with GMP, which includes quality control testing, and that certification programs, supplier agreements and third-party testing are further tools against adulteration. [6] See what third-party testing can and cannot show and contamination, adulteration and recalls.Frequently asked questions
What does cGMP stand for?
Current good manufacturing practice. For dietary supplements the US rule is 21 CFR Part 111. [9]
Does FDA approve supplement factories?
FDA says it does not approve facilities. [3] It does require facilities to register and can inspect them. [2]
Does cGMP mean every product is tested for what is on the label?
The rule requires identity testing of dietary ingredients and finished-batch verification on a subset chosen by a sampling plan, or on every batch. [1] It does not say FDA tests every product; FDA says it does not test supplements before sale. [2]
Is a "GMP certified" claim the same as FDA approval?
No. FDA does not approve facilities. [3] What a particular "GMP certified" claim means is not described in the sources we read.
Where can I report a quality problem?
FDA's Safety Reporting Portal takes reports of adverse events and product problems such as foreign objects or quality defects. [2] See side effects and reporting.
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Safety and who should ask a clinician
References
- eCFR: 21 CFR Part 111, Current Good Manufacturing Practice for Dietary Supplements (source 72 FR 34942, 2007) Read 2026-10-23.
- FDA: Questions and Answers on Dietary Supplements (content current 27 Aug 2026) Read 2026-10-23.
- FDA: Avoiding Products Contaminated with Hidden Ingredients (content current 10 Jun 2025) Read 2026-10-23.
- FDA: What's New in Dietary Supplements Read 2026-10-23.
- FDA: Dietary Supplements (overview, content current 1 Oct 2024) Read 2026-10-23.
- Dietary Supplement Adulteration: Laboratory Approaches to Risk Mitigation (2025) Read 2026-10-23.
- NCCIH: Using Dietary Supplements Wisely Read 2026-10-23.
- FDA: How to Report a Problem with Dietary Supplements (content current 13 Mar 2025) Read 2026-10-23.
- FDA: Current Good Manufacturing Practices (CGMPs) for Food and Dietary Supplements Read 2026-10-23.