FDA Good Manufacturing Practices

FDA Good Manufacturing Practices

by Zoe Gardner

The Myth of “Unregulated” Herbal Products

One of the most commonly repeated myths about herbal products in the U.S. is that they are “unregulated,” and along with this comes the implication that herbal products are therefore dangerous. In the U.S., herbal products are regulated as dietary supplements, a category that includes vitamins, minerals, enzymes, amino acids, and herbal products. In some circumstances, herbal products can also be sold as over-the-counter drugs or prescription medicines. The myth of “unregulated” products comes from the fact that dietary supplements, including herbal products, have different regulations than drugs or OTC products. Dietary supplements do not require FDA approval prior to sale, but companies must instead notify the FDA of each new product that is launched, have evidence on hand to demonstrate that the product is safe for its intended use, and have evidence available to support any claims that are being made on the product. Claim language is closely regulated. Only structure-function claims are permitted. This means that any claims must be based on how the product effects the structure or function of the body (i.e. calcium supports strong bones), and products may not claim to treat any disease or condition.

Good Manufacturing Practices

In 2007, FDA published the Good Manufacturing Practices (GMPs) for dietary supplements which are in effect today. Compliance with GMPs requires ingredient and product testing and extensive paperwork to ensure that the manufacturing process for each product is properly designed, controlled, and monitored. GMPs help to ensure that products are consistent from batch to batch and that each product is properly made with all of the correct ingredients, at the right dose, and no unwanted ingredients, helping to ensure product safety and efficacy. As part of GMP compliance, FDA requires that companies do testing to ensure the “identity, purity, strength, and composition” of each ingredient and product.

Proper identification of ingredients is essential for herbal products and has been a key concern for FDA. In some cases, identification is relatively easy, when whole or nearly whole herbal ingredients are received by the manufacturing company. As the size of the herbal ingredient gets smaller, as with a finely cut herb or powdered herb, identification becomes more difficult and more expensive to do properly. Herbs that are processed into rough cut or fine cut can be identified through traditional methods such as macroscopic identification (using the naked eye to identify visible characteristics), microscopy (examining visible characteristics under a microscope), and organoleptic evaluation (using smell, taste, and other senses). Because botanical features cannot be seen in powders or extracts, these forms require chemical methods of identification along with organoleptic evaluation. One of the best steps to ensure proper identity of herbal ingredients is to observe the plants in the field prior to harvest, this observation along with careful documentation at each step of processing helps ensure that the finished products will contain the correct herbs.

Purity, Strength and Composition

With proper identification as the foundation for a GMP-compliant product, manufacturers must also evaluate each batch of ingredients and products for purity, strength, and composition. For each herbal product, FDA does not provide required testing but instead requires that each manufacturer determine their own set of tests for every ingredient and finished product. The manufacturer must be able to justify that the tests used are suitable for the ingredients or products being tested and that the test methods are scientifically sound. Tests for purity and composition might include foreign matter tests (observing herbs under a microscope to make sure that the herbs are free of weeds), heavy metal testing, and microbial testing. Strength testing most often uses contemporary methods such as chromatography to measure the amount of a select compound, but can also use more traditional methods such as distillation to measure the content of essential oil or “bitterness value” to determine the level of bitterness. Every ingredient and finished product needs to have a specification that details exactly which tests are to be conducted in order to demonstrate the identity, purity, strength, and composition of the ingredient or product.


Good manufacturing practices require an impressive amount of paperwork to document that each step of the manufacturing process, and all ingredient and product testing has been completed as planned. Paperwork, which starts as soon as an herb is harvested, ensures that each crop of herbs can be traced from the field, to the processing facility, to the manufacturing facility, to the finished product, and then to where the herb is sold.

For a broader discussion of quality in terms of cultural, ecological and economic sustainability, watch Quality and Sustainability.

For information on specific procedures, examples of templates etc. see AHPA Resources.