Dietary and Herbal Supplements - Background Information
What is a dietary supplement?
As defined by Congress in the Dietary Supplement Health and
Education Act, which became law in 1994, a dietary supplement is
a product (other than tobacco) that
- is intended to supplement the diet;
- contains one or more dietary ingredients (including vitamins;
minerals; herbs or other
- botanicals; amino acids; and other substances) or their constituents;
- is intended to be taken by mouth as a pill, capsule, tablet,
or liquid; and
- is labeled on the front panel as being a dietary supplement.
What is a new dietary ingredient?
A new dietary ingredient is a dietary ingredient that was not sold
in the United States in a dietary supplement before October 15,
Are dietary supplements different from foods and
Although dietary supplements are regulated by the U.S. Food and
Drug Administration (FDA) as foods, they are regulated differently
from other foods and from drugs. Whether a product is classified
as a dietary supplement, conventional food, or drug is based on
its intended use. Most often, classification as a dietary supplement
is determined by the information that the manufacturer provides
on the product label or in accompanying literature, although many
food and dietary supplement product labels do not include this information.
What claims can manufacturers make for dietary supplements
The types of claims that can be made on the labels of dietary supplements
and drugs differ. Drug manufacturers may claim that their product
will diagnose, cure, mitigate, treat, or prevent a disease. Such
claims may not legally be made for dietary supplements.
The label of a dietary supplement or food product may contain one
of three types of claims: a health claim, nutrient content claim,
or structure/function claim. Health claims describe a relationship
between a food, food component, or dietary supplement ingredient,
and reducing risk of a disease or health-related condition. Nutrient
content claims describe the relative amount of a nutrient or dietary
substance in a product. A structure/function claim is a statement
describing how a product may affect the organs or systems of the
body and it can not mention any specific disease. Structure/function
claims do not require FDA approval but the manufacturer must provide
FDA with the text of the claim within 30 days of putting the product
on the market. Product labels containing such claims must also include
a disclaimer that reads, "This statement has not been evaluated
by the FDA. This product is not intended to diagnose, treat, cure,
or prevent any disease."
How does FDA regulate dietary supplements?
In addition to regulating label claims, FDA regulates dietary supplements
in other ways. Supplement ingredients sold in the United States
before October 15, 1994, are not required to be reviewed by FDA
for their safety before they are marketed because they are presumed
to be safe based on their history of use by humans. For a new dietary
ingredientone not sold as a dietary supplement before 1994the
manufacturer must notify FDA of its intent to market a dietary supplement
containing the new dietary ingredient and provide information on
how it determined that reasonable evidence exists for safe human
use of the product. FDA can either refuse to allow new ingredients
into or remove existing ingredients from the marketplace for safety
Manufacturers do not have to provide FDA with evidence that dietary
supplements are effective or safe; however, they are not permitted
to market unsafe or ineffective products. Once a dietary supplement
is marketed, FDA has to prove that the product is not safe in order
to restrict its use or remove it from the market. In contrast, before
being allowed to market a drug product, manufacturers must obtain
FDA approval by providing convincing evidence that it is both safe
The label of a dietary supplement product is required to be truthful
and not misleading. If the label does not meet this requirement,
FDA may remove the product from the marketplace or take other appropriate
What information is required on a dietary supplement
FDA requires that certain information appear on the dietary supplement
- Name of product (including the word supplement or
a statement that the product is a supplement)
- Net quantity of contents
- Name and place of business of manufacturer, packer, or distributor
- Directions for use
Supplement Facts panel
- Serving size, list of dietary ingredients, amount per serving
size (by weight), percent of Daily Value (%DV), if established
- If the dietary ingredient is a botanical, the scientific name
of the plant or the common or usual name standardized in the reference
Herbs of Commerce, 2nd Edition (2000 edition) and the name of
the plant part used
- If the dietary ingredient is a proprietary blend (i.e., a blend
exclusive to the manufacturer), the total weight of the blend
and the components of the blend in order of predominance by weight
- Nondietary ingredients such as fillers, artificial colors, sweeteners,
flavors, or binders; listed by weight in descending order of predominance
and by common name or proprietary blend
The label of the supplement may contain a cautionary statement
but the lack of a cautionary statement does not mean that no adverse
effects are associated with the product.
Does a label indicate the quality of a dietary
It is difficult to determine the quality of a dietary supplement
product from its label. The degree of quality control depends on
the manufacturer, the supplier, and others in the production process.
FDA is authorized to issue Good Manufacturing Practice (GMP) regulations
describing conditions under which dietary supplements must be prepared,
packed, and stored. FDA published a proposed rule in March 2003
that is intended to ensure that manufacturing practices will result
in an unadulterated dietary supplement and that dietary supplements
are accurately labeled. Until this proposed rule is finalized, dietary
supplements must comply with food GMPs, which are primarily concerned
with safety and sanitation rather than dietary supplement quality.
Some manufacturers voluntarily follow drug GMPs, which are more
rigorous, and some organizations that represent the dietary supplement
industry have developed unofficial GMPs.
Are dietary supplements standardized?
Standardization is a process that manufacturers may use to ensure
batch-to-batch consistency of their products. In some cases, standardization
involves identifying specific chemicals (known as markers) that
can be used to manufacture a consistent product. The standardization
process can also provide a measure of quality control.
Dietary supplements are not required to be standardized in the
United States. In fact, no legal or regulatory definition exists
in the United States for standardization as it applies to dietary
supplements. Because of this, the term standardization
may mean many different things. Some manufacturers use the term
standardization incorrectly to refer to uniform manufacturing practices;
following a recipe is not sufficient for a product to be called
standardized. Therefore, the presence of the word standardized
on a supplement label does not necessarily indicate product quality.
What methods are used to evaluate the health benefits
and safety of a dietary supplement?
Scientists use several approaches to evaluate dietary supplements
for their potential health benefits and safety risks, including
their history of use and laboratory studies using cell or animal
models. Studies involving people (individual case reports, observational
studies, and clinical trials) can provide information that is relevant
to how dietary supplements are used. Researchers may conduct a systematic
review to summarize and evaluate a group of clinical trials that
meet certain criteria. A meta-analysis is a review that includes
a statistical analysis of data combined from many studies.