Exactly How To Determine The Quality Of Your Vitamins + Supplements

Exactly How To Determine The Quality Of Vitamins + Supplements Like A Pro Dr. Will Cole

If you’re just starting your supplement research, you may feel overwhelmed by the choices out there. There are thousands of brands with clever marketing aimed at convincing you that they’re better than the rest.

The thing is, you really shouldn’t take their word for it — and I say that as a big proponent of supplements!

Let me rephrase that: I’m a big fan of quality supplements that help my patients reach their wellness goals.

So, how do you tell a good, quality supplement from one full of unnecessary additives, ineffective ingredients, and overblown claims? I’m here to remove some of that confusion and help you start vetting supplements like a pro.


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What Exactly Are Dietary Supplements?

Simply put, dietary supplements are products that supplement your diet to provide you with additional nutrients.

Your body relies on a variety of nutrients to thrive. If you have any deficiencies due to a poor diet or health conditions that cause malabsorption, you’re setting yourself up for a cascade of problems. Supplements, along with a healthy diet, are one way to combat that.

A healthy, balanced, nutrient-rich diet is a great way to boost overall wellness and start addressing barriers to optimal health. But in America, particularly, due to factors out of our control like soil depletion, restrictive diets, and chronic health conditions, diet alone just isn’t cutting it for many of us.

That’s where supplements come in.

Supplements are designed to support and correct nutrient deficiencies and imbalances in the body. (1) Some supplements, including nutrients you may not get even from a typical healthy diet, may also help with certain, targeted areas of your health.

Dietary supplements may come as a single vitamin or mineral or combine multiple nutrients to target certain wellness goals or deficiencies.

The supplements that we use in functional medicine often include the following:

  • Vitamins: Our bodies rely on optimal levels of vitamins like A, D, and C to function at their best.
  • Minerals/Trace elements: These include essential zinc, copper, iron, selenium, and iodine that help regulate body processes.
  • Amino acids: These are the building blocks of protein and include histidine, important to immune function, and lysine, which helps the body absorb calcium. (2)
  • Herbs: Herbs and botanicals like echinacea and ginseng come from plants, flowers, berries, or roots.

How To Determine Vitamin & Supplement Quality

Determining the quality of vitamins and supplements comes down to a few key factors. When vetting brands, focus on these areas for the best quality supplements.

1. Read The Active Ingredients

The best brands have as few ingredients as necessary. I’m not talking about single-ingredient supplements here. Some nutrients need other ingredients for proper absorption, while others include a combination of active ingredients that work toward a stated wellness goal.

For instance, if you take a supplement that contains curcumin, research tells us that your body will absorb it better when paired with black pepper. Some supplements combine scientifically effective amounts of multiple ingredients that all address the same thing, such as a women’s health supplement with several elements that may help in managing reproductive health.

Outside of gut-healthy probiotics, my favorite supplement for digestive health combines zinc with ingredients like slippery elm, aloe vera, and licorice to support a healthier gastrointestinal tract. Each added ingredient keeps digestive health in mind.

For a boost in digestive health AND an improved mood, my supplement duo of Gut + Feelings can support your journey to a healthier mind-body connection. 

2. Avoid Unnecessary Additives

Examine the label to uncover any hidden inflammatory ingredients such as grains or sugar. Avoid supplements with artificial fillers and colors that can negate the benefits of why you’re taking a supplement in the first place.

You don’t need these extra ingredients to have an effective supplement. The majority of the ingredient list should be made up of the active nutrient(s), and that’s it.

3. Science-Backed Research

Any vitamins and supplements you take should be backed by scientific research. There should be multiple studies readily available for nutrients that promise to target a certain health concern. If listed health benefits sound too good to be true, give those claims extra scrutiny.

The Food and Drug Administration (FDA) regulates unproven claims, but it’s a slow process. It’s up to us to do our research before taking supplements. A functional healthcare provider can help by offering suggestions on high-quality supplements or navigating product labels.

Note: Due to FTC and FDA regulations around supplements and their marketing, most supplement companies don’t publish scientific research on pages where they sell these products online. They may also use soft wording, even when the science is very strong. You may need to do a little more digging into the evidence-based benefits of supplement ingredients on your own to connect the dots.

4. Look For Third-Party Testing

High-quality brands take evidence-based claims a step further by testing their products through third-party sources to validate those claims. Proprietary blends are great and often trademarked in quality products, but make sure you know where any claims are coming from.

They may also test for quality and purity to ensure their nutritional supplements are free of contaminants that can affect consumers with allergies or worsen existing health conditions.

Keep in mind: Third-party testing is expensive, so many budget-friendly supplements aren’t able to do this. However, they often purchase their supplements from manufacturers who do their own third-party testing.

5. Reward Brand Transparency

You shouldn’t have to go on a wild goose chase to validate a brand’s products. When you look up a brand, they should be completely transparent about every aspect of their supplements.

That includes the quality of their ingredients, where they source them from, and their manufacturing process. That last part is regulated by the FDA, by the way, so if there’s no way to know where a product is made by looking at the label, that’s a huge red flag.

6. Read Relevant Certifications

Since supplements aren’t regulated the same way as prescription medications, some private entities and nonprofit groups have stepped up to offer a layer of brand accountability. Some of these are great, while others may not be as reliable as they seem.

What labels or certifications should you look for when buying vitamins? Certification labels from entities like NSF International, ConsumerLab, or US Pharmacopeia (USP Verified Mark) are fairly common on vitamins and supplements.

They’re not required for products to be considered among high-quality vitamins and supplements, but it does mean a brand met certain requirements to attain that label.

Be wary of supplements that claim to be “all-organic.” While it’s important to avoid potential allergens or food triggers in what you ingest, the word “organic” may not mean what you think it means when you buy a product. It may just mean that the ingredients in that supplement are from organically grown, non-GMO sources.

You’ll still need to read labels closely for trace additives.

7. Ignore The Buzz Words

This is related to overblown claims on supplement labels. Beware of buzz words like “all-natural” or “100% pure.” Supplements shouldn’t be marketed as a cure-all for anything.

First of all, the FDA has forbidden this. Second, a good healthcare professional will tell you supplements are just one piece of the wellness puzzle. A high-quality supplement should address nutritional deficits or get you closer to optimal health in areas that lack it.

It shouldn’t be used as a replacement for good health habits like a balanced diet, regular exercise, and chronic stress management.

It’s also worth mentioning here that any supplement brand turning a profit using multi-level marketing techniques likely isn’t worth your time. A brand should be able to stand on its own based on research-backed efficacy and quality formulas.

LISTEN: Longevity Secrets: Top Foods, Supplements, Mind-Body Practices, Exercises, Biohacking Tools, & Labs (Ask Me Anything!) | Dr. Will Cole

How Do Low-Quality Supplements Get Sold, Anyway?

Unlike prescription drugs, American dietary supplements don’t need FDA approval before they’re sold to the public. However, there’s still some oversight to the process.

Supplements are regulated under a series of conditions passed by the Dietary Supplement Health and Education Act of 1994 (DSHEA). Under DSHEA, supplement producers can’t make health claims without clinical research.

They also have to follow a series of Current Good Manufacturing Practices (GMPs or CGMPs) that cover things like sanitary facilities and plant maintenance. Supplement labels have to list all ingredients, dosage recommendations, and contact information for the manufacturers in case of problems.

Since supplements don’t have to be approved before they’re marketed, they can hit retailers much faster than drugs that require a more rigorous process. This can be good for consumers, as it encourages competition and can make supplements more affordable.

But it can also drive down the quality of supplements by brands who rush products to boost sales. That can make the supplement landscape more challenging to navigate, especially when it can take the FDA years to uncover overstated claims in the supplement industry. (3)

Where To Buy The Highest-Quality Vitamins

Finding high-quality brands that suit your needs is more important than where you buy your supplements, whether that’s a bigger retailer or an online shop. A plus of store-brand vitamins and supplements is that they’re likely restocked frequently.

I have to plug my own shop here if you want supplements from a trusted source. The manufacturing process and sourcing of ingredients are unparalleled, and I designed the blends myself to get you the nutrients you need most efficiently.

Which Supplements Do You Need?

There is no one-size-fits-all for supplements. While I see that many of my patients are lacking in magnesium or vitamin D, that doesn’t mean you are. Ultimately, everyone’s biochemistry is unique, and there are a few things I always consider before recommending supplements.

1. Learn Your Deficiencies

The first step in finding out which supplements are right for you is to identify any nutrient deficiencies. (4) Blood work is the most effective way to identify what you need. Any existing symptoms can help guide the right testing.

You should consider your health goals here, too. Some supplements target gut dysfunction or hormonal imbalances. (5) Others support mental health. You may not be in the deficient range on a nutrient but low enough in something that it’s affecting how you feel.

@drwillcole Feeling stressed? You're not alone. Today's world feels like a non-stop stress marathon. With 77% of us feeling the effects of stress, it's clear we need to take a breather and focus on our mental well-being. 🧠 In honor of May being Mental Health Awareness Month, I'm highlighting my go-to supplements for not only relaxation but internally reversing the signs of oxidative stress. Magnesium helps to control the chemical messengers (neurotransmitters) in the brain, resulting in a calming effect on the body. Magnesium may help to manage your stress response system and cortisol levels. CoQ10 helps to reduce oxidative damage that leads to muscle fatigue, skin damage, and brain and lung diseases. Ashwagandha, an adaptogenic herb revered in traditional Ayurvedic medicine, has gained recognition for its stress-relieving and mood-enhancing properties. Check out a recent article I posted to my website for more on my recommendations for mental wellness and a balanced mood. And shop my supplements now at shop.drwillcole.com If you're feeling stuck with symptoms and don't know where to turn, functional medicine may be the key. Visit www.drwillcole.com for more info. #stresssupplements #ashwagandha #coq10 #magnesium #magnesiumpowder #drwillcole #functionalmedicine ♬ original sound - Dr. Will Cole

2. Get The Right Dosage

The right dosage isn’t always based on label recommendations, although a supplement company can’t legally tell you to take more than what’s on the label. Your practitioner may recommend high doses of a supplement in the short term, then taper you off once symptoms or deficiencies are addressed.

Some underlying health problems, like leaky gut syndrome, can impact the absorption of supplements, making a higher dosage essential. (6) You may also need to adjust the exact type or dosage of some nutrients you supplement with if you have methylation issues.

I don’t recommend going beyond a recommended dose if you’re not working with a healthcare provider who knows how to prescribe specific dosages. Low doses may not make much of a difference for you, but excessive doses can be toxic, especially for certain supplements. (7)

3. Consider The Delivery

You want supplements that are easy to ingest. If you hate pills, gummy vitamins may work better for you. Others come in powder form, tinctures, or topical creams.

You also want to consider bioavailability. Liposomal vitamin C comes in the form of a liquid gel inside a single-serve packet. This form boosts its bioavailability over traditional vitamin C capsules, getting your body what it needs more efficiently. (8)

Supplements for Overall Wellness

If you’re not looking to address a specific health problem and just want well-rounded support, I’ve found that most people can benefit from a handful of targeted supplements. This list covers your bases when it comes to all areas of your health:

These 9 supplements are available as a bundle I call The Essentials. All 9 work synergistically together to support optimal wellness.

Get The Essentials Bundle

Dr. Will Cole's Personal Picks

To Elevate Your Wellness

Is There Anyone Who Shouldn’t Use Supplements?

Individual results can vary even with high-quality supplement brands, but if you’re pregnant, breastfeeding, or on medications for pre-existing conditions, start by talking to your doctor.

They will be able to help with the nuances. For instance, I recommend black cohosh for menopause symptoms, but pregnant women should avoid the herb for its potential labor-inducing effects. (9) Fish oil and turmeric are known antioxidants that may reduce your heart disease risk, but they may amplify the effects of blood thinners. (10, 11)

These are just a few examples. Allergies and underlying health conditions are also important considerations. The point is, you shouldn’t be getting medical advice from an over-the-counter supplement label if you’re in a high-risk category for interactions.

The Takeaway

The best vitamins and supplements for you depend on what you’re hoping to achieve with supplements. Once you narrow that down, you now have the tools to move forward with confidence and find supplements that meet your needs.

If you want to simplify things for yourself, we provide webcam health consultations for people around the globe that can include a personalized list of recommended supplements.


Store supplements based on label recommendations. Typically, that means storing them in a cool, dry place away from sunlight and moisture. High heat and humidity can degrade their potency. Most supplements don’t need refrigeration, but some do.

Keep supplements tightly sealed in their original containers to maintain freshness. Monitor expiration dates and keep them out of reach of children.

When choosing a new multivitamin or supplement, seek out reputable brands with transparent labeling and ingredient lists that are easy to follow and understand.

Consider any potential drug interactions or side effects of long-term use. Choose a form that you’ll stick with based on personal preference, dosage recommendations, or ease of consumption.

Most importantly, make sure supplements include the nutrients you need for any known deficiencies or health concerns.

Using single-ingredient supplements isn’t always best. Some vitamins and minerals need other ingredients to support maximum absorption. High-quality supplements also include ingredients that complement one another to target certain health goals or conditions.

It’s more important to make sure that any supplement ingredients on a label are necessary and clinically effective.

Organic supplements may align with sustainability and environmental values, but true organic supplements are relatively rare. Certification standards vary, so it’s hard to verify claims of brands that call their supplements organic if they’re not labeled USDA Organic.

Much more often, supplement brands (like mine) will source organic ingredients whenever possible. These will be labeled as organic on the ingredients list.

It’s more important to focus on overall product quality, efficacy, and safety standards when buying supplements.

Vitamins & Supplements: Key Terms to Know


These plant-based substances may help your body adapt to stress. They’re often found in herbal substances.


These substances protect cells from damage caused by free radicals. This may reduce oxidative stress and potentially reduce your risk of chronic diseases. (12)


This is the degree and rate at which a nutrient is absorbed and used by the body after it’s consumed. Certain foods or added ingredients can boost the bioavailability of a supplement.

Daily Value (DV)

This number gives you the percentage you’re getting of the recommended daily intake of a nutrient. That number often goes beyond 100% on many vitamins and minerals. That doesn’t signal that it’s dangerous. The DV is an amount just above what you’d need to avoid deficiency-related symptoms.

Fat-Soluble Vitamins

These vitamins are dissolved in fats. Vitamin E, A, D, and K are the only fat-soluble vitamins. When they’re in excess in the body, they’re stored for future use. You shouldn’t take these to excess.

Herbal Supplement

These dietary supplements contain plant extracts or botanicals traditionally used for medicinal or health purposes.


Methylation is a chemical process that happens when a methyl group is added to another molecule. This process plays a role in how your body makes proteins, detoxification, neurotransmitter regulation, and DNA repair.


Multivitamins contain many vitamins and minerals that are essential to your health. Those with a nutrient deficiency due to malabsorption conditions, poor diet, or hormonal changes may benefit.

Water-Soluble Vitamins

These vitamins are easily absorbed by the body. They include vitamin C and vitamin B-complex. They generally aren’t stored in the body, so they need to be replenished regularly.


ZMA stands for zinc magnesium aspartate. It’s a combination supplement that includes zinc, magnesium, and vitamin B6.

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  1. Rautiainen, S., Manson, J.E., Lichtenstein, A.H., et al. (2016). Dietary supplements and disease prevention - a global overview. Nature Reviews Endocrinology, 12(7), 407-420. 
  2. Mine, Y. & Zhang, H. (2015). Anti-inflammatory effects of poly-L-lysine in intestinal mucosal system mediated by calcium-sensing receptor activation. Journal of Agricultural and Food Chemistry, 63(48), 10437-1047. 
  3. Li, W. & Wertheimer, A. Narrative review: The FDA's perfunctory approach of dietary supplement regulations giving rise to copious reports of adverse events. Innovations in Pharmacy, 14(1), 10.24926/iip.v14i1.4989.
  4. Dickinson, A., Blatman, J., El-Dash, N., et al. (2014). Consumer usage and reasons for using dietary supplements: report of a series of surveys. Journal of the American College of Nutrition, 33(2), 176-182. 
  5. Kiani, A.K., Bonetti, G., Donato, K., et al. (2022). Dietary supplements for intestinal inflammation. Journal of Preventive Medicine and Hygience, 63(2 Suppl 3), E214-E220. 
  6. Camilleri, M. (2019). Leaky gut: mechanisms, measurement and clinical implications in humans. Gut, 68(8), 1516-1526. 
  7. Phua, D.H., Zosel, A., & Heard, K. (2009). Dietary supplements and herbal medicine toxicities-when to anticipate them and how to manage them. International Journal of Emergency Medicine, 2(2), 69-76. 
  8. Gopi, S. & Balakrishnan, P. (2021). Evaluation and clinical comparison studies on liposomal and non-liposomal ascorbic acid (vitamin C) and their enhanced bioavailability. Journal of Liposome Research, 31(4), 356-364. 
  9. Dugoua, J.J., Seely, D., Perri, D., et al. (2006). Safety and efficacy of black cohosh (Cimicifuga racemosa) during pregnancy and lactation. The Canadian Journal of Clinical Pharmacology, 13(3), e257-61. 
  10. Liao, J., Xiong, Q., Yin, Y., et al. (2022). The effects of fish oil on cardiovascular diseases: systematical evaluation and recent advance. Frontiers in Cardiovascular Medicine, 8, 802306. 
  11. Burkina, V., Zamaratskaia, G., & Rasmussen, M.K. (2022) Curcumin and quercetin modify warfarin-induced regulation of porcine CYP1A2 and CYP3A expression and activity in vitro. Xenobiotica, 52(5), 435-441. 
  12. Pisoschi, A.M., Pop, A., Iordache, F., et al. (2021). Oxidative stress mitigation by antioxidants - An overview on their chemistry and influences on health status. European Journal of Medicinal Chemistry, 209, 112891. 

The information on this website has not been evaluated by the Food & Drug Administration or any other medical body. We do not aim to diagnose, treat, cure or prevent any illness or disease. Information is shared for educational purposes only. You must consult your doctor before acting on any content on this website, especially if you are pregnant, nursing, taking medication, or have a medical condition.

Our content may include products that have been independently chosen and recommended by Dr. Will Cole and our editors. If you purchase something mentioned in this article, we may earn a small commission.



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Dr. Will Cole, DNM, IFMCP, DC is a leading functional medicine expert who consults people around the globe, starting one of the first functional medicine telehealth centers in the world. Named one of the top 50 functional and integrative doctors in the nation, Dr. Will Cole provides a functional medicine approach for thyroid issues, autoimmune conditions, hormonal imbalances, digestive disorders, and brain problems. He is the host of the popular The Art Of Being Well podcast and the New York Times bestselling author of Intuitive Fasting, Ketotarian, The Inflammation Spectrum and the brand new book Gut Feelings: Healing the Shame-Fueled Relationship Between What You Eat and How You Feel.

Gut Feelings Dr. Will Cole 6

Gut Feelings

Healing The Shame-Fueled Relationship
Between What You Eat And How You Feel