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3 Markers of Quality: A Supplement Shopper's Guide

  • 5 min read

Finding products you can trust is hard. We’re here to help.

You’ve decided to take a supplement.  Perhaps it’s Fish Oil, Vitamin D, or a probiotic. Now what?

If you go online, or to the vitamin aisle at your local grocery store, you’re immediately hit with bottle after bottle . . . seemingly endless options, all looking quite similar.  How to choose which brand to buy? How to know if the ingredients inside the bottle match what’s on the label? 

Many people assume that vitamins and other supplements are subject to regulatory review and approval before sale, like pharmaceutical products. That’s not the case.  In the U.S., it is the manufacturer and not a regulatory agency that is meant to ensure the product’s safety.   People may also assume that a state or federal agency is policing the market to make sure that the product-ingredient identity and strength matches the label.  Unfortunately, that’s also not true.

In the absence of government oversight, independent third-party testing services have emerged to provide quality certifications for products and manufacturing-facilities.  To be clear: many products are safe and meet the brand and label promise, and many take the extra step of obtaining third-party certifications.  It is not un-common, however, for testing services to find products that contain either significantly less or significantly more of an ingredient than advertised on the label.  It’s also alarmingly common to find products contaminated with unlabeled ingredients or potential toxins.

And that’s one reason we started Mimi & Boo: we wanted to solve this problem and build trust through complete transparency on sourcing, scientific research and testing.  We’re committed to providing only the highest-quality products without fillers or junk, free from contaminants and, and remaining true to the label. But until your Mimi & Boo supplements are ready to ship (😉) we recommend relying on certifications from third-party testing organizations to narrow your search.  Their “seal of approval” can provide you with confidence that what’s in the bottle matches what’s on the label.

Side Note: We've also written an article on which websites provide the best information on specific supplement products.  You can find it here.

Below is an overview of the three most-recognizable testing organizations and an explanation of what their “seal of approval” means.

1. U.S. Pharmacopeia (USP)

The U.S. Pharmacopeia (USP) is a non-profit organization that develops and publishes standards for drugs and dietary supplements.  These standards constitute the United States Pharmacopeia–National Formulary (USP–NF), and have been recognized in the Federal Food, Drug and Cosmetic Act since it was first enacted in 1938.

In response to demand from manufacturers, USP created the “USP Verified” program in 2001.  This is a voluntary program through which products are independently tested against USP standards and can earn the USP certification. The USP Verified mark is considered by many in the industry to be the “gold standard” for supplement verification.

 USP Verified Mark

The "USP Verified" Mark

According to USP, “[i]nstead of just pulling product off shelves and testing them, we work with manufacturers to ensure they have the appropriate quality assurance protocols in place to ensure quality is built into the product.  We meet the company owners, we inspect their manufacturing facilities, we review their files to see where they are sourcing their ingredients, how their supplements are made, what methods they use to test both the ingredients and the final products, and whether those tests are appropriate for the product and capable of identifying harmful contaminants like heavy metals, pesticides, and microbes. And finally, we test their products against science-based quality standards.”

Manufacturers pay to participate in the program, of course, and to earn the USP Verified mark their products must have been proven to:

  • contain the ingredients listed on the label, in the declared strength and amount,
  • not contain harmful contaminants,
  • break down and dissolve within a specified amount of time so that they can be absorbed by the body, and
  • be produced in accordance with Good Manufacturing Practices, using sanitary and well-controlled processes.

For products in the USP Verified Program, USP will conduct facility audits each year and will retest products one to six times per year by purchasing them off store shelves.

The supplement information websitemaintained by USP is free.  It provides a list of verified products and brands, as well as resources such as an infographic on how to read a supplement label and links to supplement-related articles.

2. NSF International

NSF International (NSFI) is a non-profit, non-governmental organization that tests and certifies both nutritional supplement products and the facilities in which they are produced. NSFI was the first to develop an independent testing standard and product certification program strictly for dietary supplements – referred to as the NSF American National Standard for Dietary Supplements (or NSF / ANSI 173).  NSFI maintains its own testing laboratories in the U.S., China and Germany and provides facility audits in the Americas, Europe and Asia.

According to NSFI, the NSFI certification process includes “a toxicology and label review to verify product formulation and marketing claims, testing to identify and quantify dietary ingredients declared on the product label, testing to ensure the product does not contain unacceptable levels of contaminants, and twice annual Good Manufacturing Practices (GMP) facility inspections.” 

The inclusion of facility inspections sets NSFI apart from CL.  As is the case with CL and USP, supplement companies or manufacturers pay NSFI to have their products and facilities tested and certified. If a product passes the NSFI criteria then it can license the NSF seal to display on the supplement packaging.

NSF International Seal

The NSF International Seal[

The NSFI website is not as user-friendly or information rich as  It doesn’t provide rankings of products, as CL does, but at no cost you can search to see if particular nutritional supplements or facilities are NSFI certified.

3.  Consumer Lab (CL) is a for-profit company that contracts with independent laboratories to test a wide selection of health and wellness products, including vitamins and other supplements. CL does not receive any payment from manufacturers to carry out their tests. Instead, CL makes money by licensing its “seal of approval” to manufacturers for use on products that pass through the CL quality certification program and meet testing criteria.  In addition, the company funds its testing by subscription fees paid by consumers, libraries, hospitals, and other institutions.

The CL testing criteria comprise the presence of stated ingredients in the stated amounts, the absence of contamination (e.g.; lead or arsenic) and the speed at which the product will break down and dissolve so that it can be absorbed by the body.  For this CL uses the USP standards described above.

To ensure that their results will align with the actual consumer experience, Consumer Lab staff pull products directly from store shelves rather than testing products sent to them by the manufacturers. Manufacturers whose product meets the CL quality standards can display the “CL Approved” seal on product bottles but must agree to have their product re-tested every year.

Consumer Lab Approved Seal

The "Consumer Lab Approved" Seal

If you are curious about a certain brand or type of supplement, you can go to the website and search directly from the homepage.  A subscription is required for full access to test results and information.

Bottom Line

Because it is not subject to the same tight regulation as the pharmaceutical market, the supplement market can be difficult to navigate. If you have supplements in your cabinet at home, you can go to the websites we recommend to search by brand or by product.  Look for seals from US Pharmacopeia, Consumer Lab or NSF International for assurance that what's in the bottle matches the description on the label and that your product is free from contaminants.  



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