Americans are investing in their health more now than ever before. Globally, the dietary supplement market has grown from $115 billion to $151 billion in sales each year. We are using vitamins, protein powders, probiotics, fish oil, and more to support our health. But not all supplements are created equal. In fact, regulations for these products are not adequately enforced and the burden falls on the supplement company to develop and test a quality product.

Do you trust the company that makes your fish oil or your probiotic? If you don’t know them from Adam then take a look at the recommendations in this blog to shop for high-quality supplements for you and your family. Consumers and clinicians need to stay informed and work together to select safe, quality supplements. After all, we take supplements to improve our health, not harm it.

This blog follows up on my earlier article, “Buyer’s Guide to the Best, High-Quality Supplements for You and Your Family,” which was extensively researched.


Thank you to our sponsor, DaVinci Laboratories, for making this blog possible.

When looking for high-quality supplements, you can trust DaVinci with almost 50 years of experience and leadership in the supplement industry. Innovative, evidence-based, and a family company, I have been using and recommending their products for over 15 years.

Are You Buying Quality Supplements?

Supplements can contain toxins, they can be cut or laced. They might be fake. Or they may have none of the active ingredients that they claim on the label.

Recent Headlines from ConsumerLabs, a Third Party Testing Laboratory, Read:

  • “Problems with Supplements on Amazon”
  • “Not All Quercetin Supplements Contain What They Claim”
  • “USDA Organic Seal Does Not Guarantee Free of Heavy Metals”
  • “50% of Red Yeast Rice Supplements Fail Tests”

In an analysis of 30 immune supplements for sale on Amazon, 17 were inaccurately labeled; 13 were misbranded, and 9 had additional ingredients that were not stated on the label. Even if a product is made with 100% organic ingredients, it can unfortunately still contain heavy metals because testing of ingredients and finished products for heavy metals is not required for USDA Organic products. In over-the-counter brands of red yeast rice, testing showed that they didn’t contain the active ingredient to lower cholesterol and/or they contained high levels of a possible kidney toxin, citrinin.

Toxins in supplements are not always due to malicious intent. Some toxins are naturally occurring in plants. For example, arsenic is naturally occurring in rice and apples. Cadmium is found in chocolate. These plants take them up from the soil they are grown in. Toxins can be introduced with manufacturing or processing of the materials, even before they have been bottled.

If a supplement is high in arsenic, it doesn’t mean that the supplement company is trying to poison you. They just haven’t tested the supplements or selected better sources of the product. Herbs and spices are prone to these same issues as well as ashwagandha root, Echinacea, and green tea leaves.

Whether you are a clinician or a consumer, supplement quality issues can leave your head swimming.

How can you buy supplements safely? It all comes down to the company and if you can trust them. Third party testing of supplements helps you figure that out.




What is Third Party Testing?

When a supplement is 3rd party tested, it means that an outside organization is testing it for purity, toxicity, or that it contains exactly what the label says it contains. Obviously, a great benefit of 3rd party testing is that it uses an independent, unbiased entity to test the product. An employee of the supplement company is not going to expose the flaws of its product! When a supplement is third party tested, it also indicates to me that the company or supplement brand is serious about quality. Third-party testing isn’t cheap and sometimes it turns up bad news. A product might fail tests and then the company would have to spend time and money figuring out a new source of the ingredient. Third party testing holds supplement companies accountable. When I see that a supplement company is using third party testing, it builds my confidence that the company and its products are trustworthy. Claims such as “Third Party Tested” or “Quality Tested” are not themselves enough. Look for certification marks or recognizable seals.

So, the Supplement Brand is Third Party Tested. What Else Do You Need to Know?

Just because one supplement, such as calcium, from a company is third party tested, it doesn’t mean they all are. So, if you’re concerned, you can check with the company. I have asked companies for specification sheets on supplements I bought. Here is one for a multiminerals supplement from Prothera Klaire Labs. This one appears to be tested by their in-house laboratory and shows that they tested and verified the amounts of each mineral in the supplement. They checked it for bacterial and fungal contamination. And they looked for the presence of heavy metals.


Certificate of Analysis

Click to open the full PDF



Here is another product quality report showing a DaVinci Labs fish oil supplement tested by a third-party lab, NutraSource/IFOS. It shows that the amounts of omega-3 fatty acids found in the product match the label. It tests for toxins such as PCBs, which are known to be high in fish. It checks for oxidation byproducts to make sure the fish oil is fresh and it makes sure levels of heavy metals are very low or undetectable.



IFOS Report Page 1

Click to open full PDF

IFOS Report Page 2

Click to open full PDF



If you buy supplements from a trusted clinician, they should also be asking the supplement company for this information. While it may be easy to turn a blind eye to quality and just gulp down your vitamins and supplements, it’s not a good idea.

Just because a product is third party tested, it doesn’t mean that it is third party tested for everything. Let’s consider toxins. There are hundreds of thousands of toxins out there in the world. It would be financially impossible for a company to test a product for all of them! So usually, third party testing is focused testing based on known risks. Mercury in fish oil. Lead in calcium.

Consumer protection services do third party testing on a wide spectrum of supplements, across many brands. I really like Consumer Labs for testing over-the-counter supplements. They are a champion for customer safety when it comes to supplements. They test supplements and they give the results. It helps consumers stay safe and make wise choices. It holds supplement companies accountable for their product quality. My only complaint is that they don’t test enough professional-only supplement brands.


Tips for Selecting High Quality Supplements


  • Read the label.
  • Avoid products with unrealistic claims such as that it treats a disease.
  • Avoid products with unverified claims, such as “quality tested.”
  • Check out the company’s website and quality page.
  • Ask an experienced integrative and functional medicine practitioner.
  • Look for 3rd party testing with a certified mark or reputable laboratory listed.
  • If on Amazon, look at the vendor/who’s shipping the product and determine if that company is trustworthy.
  • Call your supplement company and find out if they sell on Amazon and if so, which Amazon retailer they are.
  • Ask the supplement company for a 3rd party quality test of the supplement you plan to buy (also called a specification sheet or product report).
  • Don’t shop on price alone. You get what you pay for.
  • Check for FDA recalls or warnings.
  • Check ConsumerLabs, especially when shopping grocery store brands.
  • Gluten-free, dairy-free labels, if verifiable, may hint at more quality testing.


Consumers, shop for safe, high-quality supplements with my one-page Buyer’s Guide, which will get delivered to your inbox when you sign up for my e-newsletter.

Clinicians, you can download a customizable Buyer’s Guide to use as your own in your clinic. Atlanta Integrative & Internal Medicine laminated a copy, which they showcase in their supplement store to customers.



High Quality Supplements and Integrative and Functional Medicine

In the healthcare setting, integrative and functional medicine practitioners are the most knowledgeable about supplement quality issues. In this type of medicine, we are focused on root causes of disease. The goal is to use supplements and lifestyle as a primary method of treating patients while reducing the need for medications.

An integrative and functional supplement industry has grown up around this unique group of clinicians over the last 30+ years. Like the clinicians they serve, these supplement companies value quality, purity, accuracy in labeling, and freedom from toxins and allergens. They often promote that they are free of fillers and binders. A list of these companies can be found here.


Integrative and functional medicine practitioners often sell these trusted supplements in their offices to patients. They take supplements themselves. They may request quality tests of the products. If you don’t already have an integrative and functional medicine healthcare practitioner on your team to consult with about supplement quality, find one using the resources at the end of this blog.

Some of these companies are branching out from professional-only customers and selling directly to consumers. Some even have a presence on Amazon, but you have to be sure who they are and not mix them up with other middle-men Amazon resellers. For example, DaVinci Laboratories products (from the manufacturer) are officially sold on Amazon by “FoodScience Corp.” The supplements are shipped to Amazon directly from the DaVinci facility and are labeled with DaVinci-specific barcodes to avoid co-mingling with other products in Amazon warehouses.

“I would rather take a handful of supplements than a handful of prescription medications.”

-Dr. Ellie Campbell, DO



Best Supplement Brands to Buy

In general, I think professional-only supplements are the best supplement brands to buy. I also have used, recommended, and worked with these companies for over 15 years. I know many clinicians who use them and trust them. Their clinician customers are savvy, have access to testing themselves, and have extremely sensitive patients who need pure supplements. I think these companies are held accountable by their professional customer base.

In my earlier blog on supplement quality, I argued that grocery store supplements were not the highest quality. I have to backpedal on this position now because some brands at grocery stores or mainstream retail outlets do use third party testing and have good quality. In fact, third party testing has shown that some of the best quality supplements are produced by big retailers who can make affordable supplements and hold their suppliers to high standards. That said, I would not buy supplements off the shelf at Target, Wal-Mart, or Sam’s without thoroughly doing my research on the specific product first.

Look for Supplements that Have Undergone 3rd Party Independent Testing by These Companies


You can find a list of over-the-counter grocery store supplements here that have the USP verified mark on the label, including products from Costco, Nature Made, Member’s Mark, and more.


Consumers, struggling to find affordable high-quality supplements?

Prices are at an all-time high in 2022. Let’s face it; supplements are a luxury, not a necessity. It can be hard to find supplements at a certain price point that you can trust. Here are some cost-saving ideas.

  • Clinicians, set up accounts with professional-only supplement companies
  • Consumers, find a friend who is a clinician who can sell you professional-only supplements at a discount
  • Select grocery store supplements that are 3rd party tested with the USP-certified mark
  • Shop sales at your doctor’s office pharmacy
  • Buy in bulk to keep shipping costs low
  • Identify your trusted supplement manufacturer on Amazon and buy from them
  • Get an account with ConsumerLabs and based on their reports, select supplements that are high quality and low cost.



The Future of Supplement Quality

Given the lack of government oversight of supplement quality, you might expect me to be a big proponent of increased government regulation of supplements. On the contrary.  There is certainly a need for more coordinated quality assurance throughout the industry, but I believe that the supplement industry leaders- not the FDA- are the best suited to design that system. I would like to see more consistent enforcement of existing rules and regulations. But increasing FDA involvement in this massive, lucrative, and nuanced industry could bring more problems than solutions. I would expect increased prices for companies and consumers, long delays in bringing products to market, and promising products that may never make it to market. DSHEA (the Dietary Supplement Health and Education Act), which categorized nutritional supplements as foods and not medicines, was one of the best things that happened for supplements and natural health in my view. I believe that it promoted a climate of innovation, affordability, and efficiency. The drawback was questionable quality by some irresponsible companies.

Educated customers are a critical piece to this puzzle. Even though supplements are not heavily regulated, clinicians and consumers can educate themselves about supplements. They can learn what questions to ask and what brands to trust. They can find high quality supplements and vote for them with their dollars. Companies that prioritize quality should rise to the top of the heap.


Image by Gerd Altmann from Pixabay


I think the very best people to determine quality criteria for supplements are supplement producers and third-party testers themselves, who know the products and the problems of the supplement industry intimately. I would want the supplement industry to require a minimum standard of quality and safety that still fostered innovation and affordable supplements for all. Companies that exceeded those standards could garner more sales for their higher commitment to quality. The best system of regulation would be one that the supplement industry proposed for itself and that was held accountable by an informed clinician and consumer customer base and consistently enforced by larger government authorities, such as the FDA or USDA.


Shopping for the Best Quality Supplement Brands

There are serious quality issues to contend with in the nutritional supplement industry. It’s a “buyer beware” climate. But all is not lost. There are supplement companies that pride themselves on quality and invest in quality. There are third party testing companies that help keep companies accountable and consumers informed. There are clinicians and consumers like you who take the time to learn about the dietary supplements they use and recommend. When shopping for supplements, you can use my Buyer’s Guide, research the supplement company, research the specific supplement you use, look for recognizable certification marks of third-party testing laboratories, and/or consult with a trusted integrative and functional medicine practitioner. And since there is a 150-billion-dollar worldwide supplement market, I think we all have the incentive to strive higher for safe, high-quality supplements to improve human health.



Find an integrative and functional medicine practitioner:




About DaVinci Laboratories

Since 1973, DaVinci® Laboratories has been a leader in nutritional research, product development and innovation.  Our dedication to higher integrity, and insistence on superior quality are reflections of our core values. Our team of experts is always willing to assist you in matters relating to nutrition. Today, DaVinci® continues to set new standards for quality and product innovation to keep you as healthy and informed as possible.


Cass Nelson-Dooley, M.S.

Cass Nelson-Dooley, M.S.

Cass Nelson-Dooley, MS, is a researcher, author, educator, and laboratory consultant. She studied medicinal plants in the rain forests of Panama as a Fulbright Scholar and then launched a career in science and natural medicine. Early on, she studied ethnobotany, ethnopharmacology, and drug discovery at the University of Georgia and AptoTec, Inc. She joined innovators at Metametrix Clinical Laboratory as a medical education consultant helping clinicians use integrative and functional laboratory results in clinical practice. She owns Health First Consulting, LLC, a medical communications company with the mission to improve human health using the written word. Ms. Nelson-Dooley is an oral microbiome expert and author of Heal Your Oral Microbiome. She was a contributing author in Laboratory Evaluations for Integrative and Functional Medicine and Case Studies in Integrative and Functional Medicine. She has published case studies, book chapters, and journal articles about the oral microbiome, natural medicine, nutrition, laboratory testing, obesity, and osteoporosis.