Supplements are invaluable tools in helping to create better nutritional balance. The regulations that govern how these products are manufactured and tested aren’t always concise and require some explanation. We’ve created this guide to help better understand how to find, and purchase, quality supplements from trustworthy sources.


The FDA is responsible for regulating the supplement industry but, in many instances, only steps in after the fact. That means that consumers might be exposed to harmful or ineffective products long before the FDA gets involved. There are several aspects of dietary supplements and how they are produced that anyone looking for quality and purity should be aware of. Some involve third-party testing while others are simply knowing what not to believe. Regardless, the information presented here is meant to serve as a helpful guide in understanding how to better find, purchase, and use supplements. For anyone looking for a quick recommendation, we maintain a list of the best supplement brands to help guide your purchase.

FDA & Supplement Regulation

The United States Food and Drug Administration (FDA) oversees the manufacturing, testing, and sales practices of many industries. Dietary supplements fall under the purview of this agency and are such regulated with the goal of assuring safety and honest marketing. The FDA has established and helped facilitate the establishment of many formally-worded regulations to define how supplements can be manufactured and marketed in the United States. It’s a large number of regulations and, by most accounts, a grey area at best. We’ll get into some of the types of supplement regulations defined by the FDA but first, let’s take a minute to recognize what the FDA considers a dietary supplement.

FDA Definitions

The FDA cites the lawful definition of a dietary supplement to be, at least “in part,” as products taken by mouth that contain a dietary ingredient.” It’s important to note that the FDA emphasizes the term “dietary ingredient” with the implication that supplements must only contain ingredients that could also be found in food items.

Dietary supplements can be sold just about any form, provided they aren’t “represented as conventional food or as the sole item of a meal” and that they are clearly marked as dietary supplements. Some examples of acceptable types of supplements are as follows:

  • Tablet
  • Capsule
  • Powder
  • Softgel
  • Gelcap
  • Liquid

Some common types of dietary supplements, as expressed by the FDA include vitamins and minerals, herbal products, amino acids, and enzymes. Conceivably, for these to be considered food products, one must be able to find them in nature within a consumable item. For example, magnesium is a dietary ingredient because it is found naturally in foods like rice, spinach, and meats. Aspirin is not.

Labeling Laws

Any product that wishes to be regulated as a dietary supplement must be labeled as such, explicitly. In such cases that manufacturers wish to be more specific, the FDA allows appropriate variations such as Calcium Supplement, Amino Acid Supplement, and even Herbal Supplement. Additionally, there are concerns on how ingredients must be included on labels and the types of statements allowed regarding the efficacy of ingredients.

For example, supplements aren’t allowed to be marketed as a “treatment,” “cure,” or having the ability to alleviate any “symptoms” of any medical condition. A supplement can be advertised to “support bone health” but can’t be advertised to “improve bone health,” “treat osteoporosis,” or even to “re-mineralize aging bones.” Creating FDA-Compliant supplement labels is both an art and science that, in our opinion, is still often abused by marketers.

Safety Guidelines & New Ingredients

Being that dietary supplements must only contain food ingredients; the FDA doesn’t require them to be proven safe before retail sale. Presumably, the FDA assumes that any ingredient regarded as safe for consumption in food is safe for consumption in dietary supplements. If a supplement intends to contain an ingredient that isn’t currently recognized as a dietary ingredient, however, products have to first apply to have that ingredient approved by the FDA. The following section outlines that process in further detail.

Marketing New Ingredients

Manufacturers of dietary supplements are required to notify the FDA of the use of any new dietary ingredients (NDI) that were not marketed before October 15th, 1994. In accordance with FDA ambiguity, they also highlight the fact that “there is no authoritative list of dietary ingredients that were marketed in dietary supplements before October 15th, 1994.”

For a compound to be considered “new dietary ingredients” (or an old one for that matter) it must meet the following criteria, as defined by the FDA: “vitamin; a mineral; an herb or other botanical; an amino acid; a dietary substance for use by man to supplement the diet by increasing total dietary intake; or a concentrate, metabolite, constituent, extract, or combination of any of the above dietary ingredients.”

Existing Ingredients

For an ingredient to not require FDA notification of new ingredient status, it must fall into one of the following two categories:

  1. Must be an ingredient present in the food supply that has not been chemically altered.
  2. A manufacturer must present evidence to the FDA, and gain approval, supporting claims of the safety of that ingredient as a food ingredient.

GRAS Approval

In practice, this requires manufacturers to seek an FDA approval known as Generally Regarded as Safe (GRAS). This approval indicates that an ingredient is regarded as safe for the addition to food items. Compounds such as Niacin (used to “fortify” some foods) are examples of compounds that have earned GRAS status.

New Ingredient Registration Example

Another example is Niagen, a niacin metabolite manufactured by Chromadex, which is a chemical analog to the compound Nicotinamide Riboside. Our bodies naturally convert Niacin into this compound before using it on a cellular level. However, this compound was considered a “new” ingredient because it was a chemical alteration of Niacin (an already-approved food ingredient) that wasn’t marketed as a supplement prior to October 15, 1994. The Chromadex corporation had to first seek GRAS approval status before the FDA would consider this a “new” dietary ingredient.

Practical Implications

A noteworthy by-product of such approval status is that not only can Niagen now be sold as a dietary supplement but it can also be added to food products, just like Niacin can be. That means that nasty “enriched” wheat flour could very well contain Niagen as a fortifying vitamin now, as opposed to the usual Niacin.

Source: FDA’s NDI Guidelines

Mixing Pharmaceuticals & Supplements

Dietary supplements aren’t allowed to contain any compounds that are approved as a new drug or biologic, for which clinical trials and scientific study has been completed. Once a product contains any such ingredient it can no longer be labeled as “dietary supplement.” This means that an herbal antioxidant blend isn’t allowed to contain ibuprofen and be marked as a supplement but that an over-the-counter medication such as ibuprofen could contain an herbal blend and still be marketed as an approved treatment for inflammation. The purpose of this distinction, among others, is to prevent dietary supplements from containing non-natural ingredients having able to treat certain health conditions effectively (through their use of pharmaceutical compounds) and still be marketed as natural products.

Current Good Manufacturing Practices (cGMP)

Dietary supplements aren’t subject to the more rigorous manufacturing and quality assurance practices required for the manufacture of pharmaceuticals. The FDA has released a large set of guidelines to help instruct manufacturers, across many industries, on responsible manufacturing practices. These guidelines are to ensure that products sold to consumers don’t cause them harm. There are specific rule sets for different types of manufacturing processes and different industries.

cGMP for Dietary Supplements

The rule set governing the guidelines for dietary supplement manufacturing was last updated in 2007 and is found in Chapter 21 of the Code of Federal Regulations, part 111 (21 CFR Part 111) and is titled Current Good Manufacturing Practice in Manufacturing, Packaging, Labeling, or Holding Operations for Dietary Supplements. That rule set can be read in its entirety here. Just a fair warning, it’s really long and really hard to understand. We’d argue that the FDA, when uncertain of its position on a particular matter, opts to be as ambiguous as possible. We believe our opinion is evidenced by their election to address many common concerns on a case-by-case basis, posted in a Q&A format rather than specifically-outlined regulation.

Quality Control

These guidelines establish industry-standards for more than just keeping the floors clean. cGMP guidelines cover things like batch-production records, ingredient verification processes, storage, distribution, and even the labeling of dietary supplements. In addition, they also outline the responsibility of involved parties in assuring cGMP compliance.

Contract Manufacturing

For example, many supplement brands work with another company to manufacture their products. This is common practice. Even though the “own label distributor” doesn’t have a manufacturing facility they are still responsible for asserting cGMP compliance in whichever facility they choose to contract their manufacturing too. The FDA will come down hard on anyone discovered to not be in cGMP compliance, but there is no FDA cGMP certification process. This means, at least for consumers, bad products can reach the shelves before the FDA is able to catch them.

Third Party GMP Certification

The lack of a formal FDA cGMP certification process creates a market demand that has been met by several third-party agencies. The most notable, and most respected in the industry, is the NSF International (NSF). This agency provides certification and quality guidelines for many industries ranging from Aerospace and plastics all the way to environmental sustainability and wastewater practices.

NSF International

NSF offers specific certifications for the dietary supplement industry including those for ingredient and facility. That means that an NSF-certified product can also be manufactured in an NSF-certified cGMP facility! Typically, not all supplements are NSF-certified but all those that are have been produced in an NSF-Certified cGMP facility.  Here is a full list of NSF-Certified products and facilities, ordered by name of their owner’s legal names: NSF-Certified supplements and facilities.

NOTE: This list is generated from the NSF website by using a blank search. The search parameters may change at some point and require an update.

NSF Certification & Labeling

There are some important things to understand when it comes to a supplement brand’s ability to inform consumers of NSF-Certification status. Historically, manufacturers weren’t able to place NSF-Certification labels on their products even if they were manufactured in an NSF-certified facility. To make use of the NSF mark on an actual product label, that product had to have been produced in a facility that was NSF-Certified for Sport, a novel certification asserting no ingredients banned from athletic competitions are present.

NSF Mark-Use Guidelines

The NSF now offers a Contents Tested & Certified certification for individual supplements to be allowed to express the NSF-Certified mark on their labels. This certification is newer and not fully utilized within the industry yet. In most cases, manufacturers are still in the process of integrating this certification with their products. Below is a table detailing the types of NSF mark usage companies are allowed, depending on the level of certification.

Certification TypeMarketing MaterialsWebsiteAdvertisingLabel
Registered FacilityYesYesYesNo
Contents Tested & ApprovedYesYesYesYes
Certified for SportYesYesYesYes

What one needs to pay attention to, practically speaking, is that labels of products produced in an NSF-Registered cGMP facility aren’t allowed to signify such. That means one must look to the manufacturer’s website to ensure such compliance has been taken. A facility that is FDA cGMP compliant is generally regarded to be of lower quality than one that is also NSF-Registered GMP. Not to say that one without is producing bad products; just that an extra layer of assurance is better.

United States Pharmacopeia (USP)

USP certification is another popular form of ingredient and retailer certification, though not nearly as widely used as NSF or GMP. These guidelines and certifications are provided by a non-profit group named The United States Pharmacopeia Convection and updated yearly to reflect currently agreed-upon best practices.

They have verification services for pharmaceuticals, dietary supplement ingredients, and for excipients (inactive ingredients) in addition to GMP verification services. USP-certified products are an excellent means of assuring quality and efficacious products, but in practice is less commonly used than NSF. For a full list of products, brands, and retailers of dietary supplements that have USP certification consult the following webpage:

How to Check Supplement Quality Yourself

With all this information, it’s easy to recognize the potential dangers of dietary supplements more fully. The FDA requires GMP compliance, but it won’t certify it. NSF International will certify that a facility is cGMP compliant, but manufacturers can always express that on labels. The FDA requires any ingredients not marketed before 1994 to apply for new ingredient status, but there’s no list of pre-1994 ingredients. The regulations involved in the manufacturing, certification and sale of dietary supplements creates, at best, a grey area for consumers. Knowing how to do your own research is helpful in feeling confident the supplements you choose to purchase will offer you the best results. This section covers actions you can take to research and qualify your products before purchase.

FDA Warning Letters

The FDA issues warning letters in cases where they determine cGMP violations to occur. Remember that the FDA doesn’t offer GMP certification services, and manufacturers have enough freedom to have many violations before anyone would be the wiser. Nonetheless, checking to see if there have been any FDA warning letters issued with regards to a supplement manufacturer, or specific products, can help better qualify your products before purchase. To do so, we recommend starting by searching the FDA Warning Letter Database made available by the Council for Responsible Nutrition.

NOTE: Older results from this database may give 404 errors to pages not found on the website. The FDA has, for some odd reason, chosen to archive older pages on a separate domain provided by a third party. You can access these pages from the FDA database.

Practical Advice

If you find a warning letter issued regarding your favorite supplement brand, or a new brand recommended to you by your doctor don’t freak out. Part of the process is investigating how these situations were handled, by examining the responses from manufacturers. If a manufacturer or brand has a few outdated warning letters don’t worry too much. If there are dozens of warnings, spanning across many years, it’s time to start getting alarmed.

NSF Facility Certification

As mentioned earlier, NSF International is one of the gold standards within the dietary supplement certification industry. They help certify specific ingredients, products, and manufacturing facilities. Their website offers a comprehensive listing of such certifications they’ve completed. Here, you can check the status of NSF GMP registration as well as NSF GMP Registration for Athletic Banned Substances (NSF Certified for Sport). It’s important to note that not all supplement brands will be listed because many of them contract out their manufacturing to third-party facilities. In such cases, you would have to contact the supplement brand directly and ask them who their manufacturer is (often a trade secret) and then check that facility against the above lists.

Practical Advice

Don’t stress if you’re favorite supplement brand is listed as an NSF Registered GMP facility. If they are reasonably well-known and advertise themselves as NSF Registered on their website, chances are their products are produced in an NSF-Registered GMP facility. If you’ve clicked on some random Facebook ad for a supplement you’ve never heard of, that claims to be NSF-Certified, don’t take them at their word!

Reviews Aren’t Gospel

Reading reviews of dietary supplements before purchasing is an important aspect of quality assurance, at least from a consumers’ perspective. Understanding the impressions of others can help better understand what to expect from your purchase. There are some special circumstances that are important to consider.

Negative Reviews

Many negative supplement reviews say something along the lines of “Zero stars. Horrible product. Didn’t work at all!” In other words, someone ordered that product and didn’t receive efficacious results. That doesn’t necessarily speak to any quality issues, or even indicate that you might not experience the benefits of the product.

Positive Reviews

The reviews on a manufacturers website don’t often have any assurance of being real. That’s not to say that the reviews of your favorite supplements are fake—just that they could be and you’d have no idea. Third-party retailers such as Amazon, PureFormulas, or iHerb don’t have any incentive to fake reviews of any particular brand. Sellers and the brands of products being sold there do have such incentive and often go to astounding lengths to post fake reviews with very positive regard.

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Deceptive Marketing
There are entire industries dedicated to providing manufacturers with fake reviews. Review-based ranking algorithms, such as the ones used by Amazon, make it nearly impossible to compete without favorable reviews. This creates a strong incentive to 'game' their systems through such misleading practices.

Trusted Supplement Brands

The surging demand for dietary supplements in the United States has led to an unprecedented number of new supplement brands. Many of these brands are unheard of, are only available online, and have very little credibility in our opinion. In many cases, these brands could be of as pure of quality as possible but the act of asserting such is too burdensome for most consumers to bear. Our advice is to consult with a licensed doctor about which supplement brands they believe offer the purest and most trusted quality. We recognize that this isn’t practical for many. Our site maintains a regularly-updated list of what we believe to be the best vitamin and supplement brands on the market, with many considerations.

Patented Ingredients

Dietary supplements are different from pharmaceutical drugs in many ways. One important distinction is that dietary supplements are unable to be patented because they contain ingredients found in nature. After all, it would be ridiculous to think a company could hold a patent for natural compounds. Imagine if Merck was able to hold the patent for Oxygen, Water, and Nitrogen. It seems silly, but it’s the distinction that helps separate what you can buy from your local health food store to make your knee feel better and what you have to get a prescription and visit the pharmacy to obtain.

Patented Manufacturing Processes

Natural ingredients cannot be patented but the processes by which they are produced can. If a company discovers a novel way to produce a certain type of compound they can patent that process. These types of ingredients are often included in supplements to help assure ingredient quality. These ingredients are produced from a limited number of sources, have far fewer points of possible contamination, and have often been studied under clinical settings. Some such compounds are Meriva (a turmeric extract), Opitac (a reduced Glutathione compound) and TRAACS minerals (varying forms of mineral chelates. These ingredients are still handled and processed (to a degree) by end manufacturers. However, they are much less likely to have impurities or contaminants than non-patented ingredients.

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Standardized Experience
Even manufacturers with their own facilities often utilized such patented formulations of compounds. It's an effective way to help optimize production and assure customers of product consistency. This allows the consumer to value shop with higher confidence; knowing a patented ingredient is the same regardless of brand.


The FDA serves an invaluable role in protecting the safety of American consumers. Their guidelines and regulatory actions help ensure that dangerous products don’t reach the shelves of American stores and homes of American citizens. Despite their purpose, there are many cases where the FDA only takes action after-the-fact and is unable to assure that certain products are safe for consumption.

Dietary supplements are regulated in such a way we’d describe as a “grey area” at best. There are robust guidelines to control manufacturing processes, new ingredient selection, and marketing practices by brands and manufacturers alike. Still, in many cases, there exists the possibility that inferior products would be able to reach consumers before actionable countermeasures could be taken. These might come in the form of warning letters, shutdowns, or even product recalls. These types of actions clean up messes, they don’t prevent them.

Third parties such as NSF International and the United States Pharmacopeia Convention (USP) fill a much-needed demand in the dietary supplement industry. Such organizations help manufacturers take the necessary steps to assure consumers of the quality, purity, and safety of their products. These are still not ironclad measures, but a far greater solution than relying on the FDA alone. Unfortunately, such measures are elective and not taken by every manufacturer.

Knowing which supplement brands can be trusted to produce quality products containing pure ingredients isn’t easy. Practitioner-channel supplements are always our recommendation to those looking for products they are unfamiliar with. These are the brands trusted by licensed medical professionals to deliver clinical strength results to their patients. There are plenty of other brands that offer quality products, many of which are available in health food stores.

Contacting brands directly to ask about their product testing, sourcing, and manufacturing practices is an acceptable approach if you have the time. Companies that aren’t willing to be transparent about what ingredients they use, where they come from, and how they are tested to assert identity and purity are a thing of the past. Modern corporate practices are quickly learning that companies willing to be completely transparent with their customers are most-often ones that are doing exceedingly well.

Final Thoughts

The United States is often criticized for its poor regulation of dietary supplements and pharmaceuticals. It’s true, at least in our opinion, that the FDA doesn’t provide excellent preventative measures to safeguard consumers in the dietary supplement markets. The upside is that Americans are allowed easy access to many compounds that require prescriptions in other nations as well as a wide variety of brands and manufacturers to choose from. The downside is that consumers must be vigilant in doing their due diligence and ensuring the products they buy are of pure quality.

How’d We Do?

Supplement quality is a topic that’s near and dear to our hearts. Much of the research on the potential benefits of dietary supplementation fails to account for the quality of compounds tested. If you thought this article did well in helping to explain the ins-and-outs of the supplement industry let us know by using the rating box below!

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