Supplement Testing: Why (and How) Brands Back Their Ingredients & Claims

Desiree Delane - The Upside Blog |

by | Updated: July 28th, 2023 | Read time: 7 minutes

The word “test” probably isn’t your favorite. Math tests in school and blood tests at the doctor have given this term an unfavorable turn. But when you think about it, tests are good. They help us learn; they help us improve; they help us protect ourselves.

When it comes to dietary supplements, testing is absolutely a good thing. It helps a manufacturer know that the formula is correct, it helps the brand prove its claims, and most importantly, it helps you, the consumer, feel confident and safe.

Closeup View of Beige Supplement Tablets with Blurred Out Bottle in Background to Represent Supplement Testing Concept

If you’ve ever wondered if, how, and why supplements are tested, now’s your chance to prep for a pop quiz. Let’s go through the answer key!

Supplement Testing: How it Works

The only way to know if something is “good” is to start from a good frame of reference. And that’s the whole idea behind testing. In the case of a supplement, what’s “good” includes what it is and what it’s not. It’s all written down to make it official, and this becomes the standard of reference, or “specification” against which the product will be tested every time it’s made.

Specifications for supplements share at least four common elements that define it as “good” (or “quality” in the manufacturing world): identity, composition, strength and purity. Within each of these categories are qualitative (yes/no) and quantitative (1=1) ways to identify a good match to the standard.

As a simple example, look at your vitamin D supplement:

  • Identity: It’s vitamin D, from cholecalciferol (don’t worry, your body knows what that means)
  • Composition: Vitamin D, plus any excipients, in specific ratios
  • Strength: Anything in the Supplement Facts panel (known as an “active” ingredient) – In this instance, it’s 50 mcg in one serving
  • Purity: No bugs, no heavy metals, no sneaky substances or funky residues

Here’s where testing comes in. Each of these qualities goes on the specification and is something that can be verified at a lab during the manufacturing process and before it’s shipped to you. Think about it this way: the whole purpose of testing is to prove that your supplement’s label is telling you the truth. And straight As are the only way to pass.

Need-to-know vs. nice-to-know

You have an A+ test to thank every time you swallow your supplement without thinking twice about whether you’re getting what you paid for and what should be supporting your health goals. And the good news is that since a significant amount of testing is required and regulated by the Food and Drug Administration, they’re checking grades. And this keeps brands accountable.

Before your supplement is blended up, stuffed into capsules, or sealed in a bottle, it’s tested. As part of “Good Manufacturing Practices,” each ingredient, mixture and shelf-ready product has its own specifications that have to pass muster before moving to the next step…

Does this ingredient labeled “ashwagandha” look just like ashwagandha under a microscope?

Are there 50 milligrams of magnesium in 2 capsules – like the label says?

Can any harmful bacteria be detected in a scoop of your protein powder?

Yes, yes, and no?  This product is “good” to go.

From a legal and safety standpoint, this type of testing is sufficient. But many brands don’t stop there. If your supplement says “gluten-free,” or “non-GMO,” it should be able to back that claim with test results. Or they may order additional testing to back brand values like “clean labeling,” confirming the absence of pesticides or plastics for more environmentally conscious consumers.

These types of voluntary tests are typically done by a third-party laboratory — independent of the brand or its manufacturer — with no vested interest in the nature of the results. But third-party testing gets expensive, limiting the extent and frequency of this practice on every batch. To minimize cost, smaller brands will often run these “nice-to-know” tests once or twice a year.

Materials, markers & methods…oh my!

Does supplement testing sound easy? Or simple? It’s not at all.

Specifications and reference standards help streamline the process, but every ingredient and product has to be carefully assessed to select what to test, how to test and how to interpret the results. With thousands of different ingredients in endless combinations and in many forms — capsules, tablets, softgels, gummies, powders — supplement testing is highly scientific.

Laboratory lingo is like a separate language, but here’s a couple of key terms to know. Every material (ingredient) contains one or more marker compounds that make it unique. And for every marker there’s a method to find it. If labs are treasure-hunters, markers are their gold, and methods are their compasses.

Let’s revisit our vitamin D example. Chemists in testing labs have advanced equipment that can compare the chemical structure making up the powder you see to true-blue cholecalciferol. They can also measure the amount of vitamin D in a specific quantity corresponding to your serving size (the amount of powder in 2 capsules). They’ll also use other instruments and methods to detect any potentially carcinogenic heavy metals (like lead, mercury and arsenic).

A biology lab will check for bacteria, yeast and mold by putting a sample of your supplement in a petri dish and watching for growth in an otherwise sterile space. Any signs of life beyond an extremely low threshold are tossed like spoiled milk. At the same time, a lab might be looking for life if your supplement contains probiotics. Believe it or not, labs just count up live bacteria in a grid and pull out the calculator to multiply this number for a per-capsule estimate (don’t worry, they do it a few times to check their work).

Getting a perfect score on supplement testing

While many supplements have familiar ingredients (like vitamin D) that are easy to measure, and simple formulas where each ingredient cooperates with being appraised, there’s a growing list of botanicals that are more mischievous.

The thing about testing is that it aims at exactness. So subtle differences in the species, parts and composition of plants make them more tricky to test. Testing used to be a lot easier when multivitamins ruled the market, but with the explosion of e-commerce and the nonstop revolution of science, novel supplements are now the name of the game.

To stay in step with the botanical boom in the supplement world, labs are constantly tweaking their test methods to identify and quantify bioactive compounds in leaves, flowers, roots, and more. DNA-fingerprinting is even gaining momentum to separate your turmeric rhizome from its doppelganger ginger root.  But for now, it’s not uncommon for results to be less than certain. And the puzzle gets even more complex when you combine multiple plant-derived ingredients.

While labs seek better ways of testing belligerent botanicals, quality testing is more geared toward safety and consistency. Other than easy-to-measure vitamins and minerals, the specifications on your super greens blend help ensure that the formula looks, smells, and behaves the same from batch to batch, and that it meets the requirements for contamination (like those micros and metals we mentioned).

Beyond supplement testing scores

School-based tests don’t always give the full picture of a students’ knowledge. SATs attempt to use the same test method on every learner, but each individual might display the quality of their knowledge in other ways. Likewise, supplement testing seeks a rational, efficient, cost-considerate way to provide a stamp of approval on products in a consistent fashion. But the value of some ingredients seems to transcend what can be tested.

It’s reassuring to know that your supplement is, indeed, tested, but it’s also helpful to be aware that brands might taunt with testing. Posting an up-to-date Certificate of Analysis (CoA) on each product is completely voluntary and can even be misleading. Every reputable supplement is backed by a CoA, whether or not you can see it; publishing one is not a reliable indicator of better quality or brand superiority. And unless they test in-house, most brands aren’t able to disclose test results and reveal their manufacturer or lab partner.

Any time you start or change your regimen, you should always do your homework and buy supplements from a trustworthy source. And if you’re ever in doubt, reach out to your favorite brand’s customer service and ask! If they don’t know, that’s probably your answer.

Now that we’ve won you over to the good side of testing, here’s that pop quiz! But we’ll make it easy on you (and not on your supplements):

  1. What’s tested? Everything in your Supplement Facts; Bugs are banned; Metals better be miniscule.
  2. When’s it tested? Before it hits the shelf (or your mailbox).
  3. How’s it tested? Think chem. lab – glamorous goggles and all.
  4. Why is it tested? To keep you safe on an A+ path to wellness.

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