Verywell Health's Dietary Supplement Methodology

The content of this methodology is for informational purposes only. The content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a physician or other qualified health provider with any question you may have regarding dietary supplements.

We built Verywell Health to give you expert answers to your health questions. One key piece of that is providing you with research-backed information on products you are considering purchasing to support and improve your health, including dietary supplements. 

Generally speaking, dietary supplements are not essential to many people who eat a varied diet and are not managing a health condition or multiple health conditions. However, supplements can be crucial in certain circumstances. You may consider using dietary supplements to address a nutrient deficiency, support you during a life stage such as pregnancy, prevent nutritional inadequacies as you get older, help manage a health condition or protect against future health issues, or to improve your well-being. 

Making decisions about which types of supplements to use and which brands to purchase can be challenging since supplement companies make claims about their products that are not necessarily clear, accurate, or backed by science. That is why our team of registered dietitians carefully reviews the research, interviews experts with decades of experience, and utilizes resources that are rooted in science, including the National Institute of Health’s Office of Dietary Supplements, to give you the most up-to-date and accurate information. This way you are better equipped to make decisions around dietary supplements so you can most effectively support your health.

To explain our methodology of selecting nutrition supplements to feature, we will cover the following here:

What Are Dietary Supplements?

Dietary supplements are products taken by mouth that include ingredients intended to supplement your diet, including, among others, vitamins, minerals, plant-based medicines, amino acids, and enzymes. Other popular dietary supplements include omega-3s, probiotics, and protein powders. Dietary supplements come in liquids, powders, pills, lozenges, tablets, gummies, and capsules.

Supplement Facts Label

Dietary supplements are required to come in packaging with a Supplement Facts label that lists the ingredients, amount per serving, and a suggested serving size. This label is typically found on the outer packaging or the back of the supplement container.

This information helps you know what the key active ingredients in the supplement are, as well as other inactive ingredients such as flavors, fillers, and binders. Active ingredients are responsible for the effects the supplement has on the body, while inactive ingredients are the ingredients that help maintain the supplement’s freshness, improve its flavor, and potentially make the supplement more accessible to your body. This Supplement Facts label is your guide to knowing what is—and isn’t—in your supplement. There are, however, occasions where supplements are contaminated with substances not listed on the label, as well as occasions where they contain far less or far more of listed ingredients.

You may notice a section on the label called “Other ingredients.” This commonly includes fillers and excipients, ingredients often included to help optimize the manufacturing process or bind a supplement together. Not all fillers and excipients are harmful, but they also aren’t always necessary in a product. It’s best to take a closer look to know exactly what is in your supplement, in case you are allergic or sensitive to these ingredients or they interact with other supplements or medications you are taking.

It is important to note that supplements are minimally regulated by the U.S. Food and Drug Administration (FDA), so it is up to the manufacturer to comply with labeling guidelines. Just because a label says the supplement contains certain ingredients in certain quantities, there is no guarantee that it is accurate. Additionally, these labels are not required to include expiration dates, so it is possible to purchase supplements without any accessible information about when they expire. However, if a company chooses to include an expiration date on a supplement, the FDA requires this information to be accurate.

Are Dietary Supplements Beneficial?

It is best to get our nutrients from the foods we eat, and supplementation is, in most cases, only useful when nutrient needs cannot be met through the diet or there are increased needs due to a life stage or medical condition. There are no recommendations for the general population regarding supplements because each person’s needs and risk of deficiency is different.

Supplements can be useful in specific instances, where they can help prevent nutrition gaps, correct nutrient deficiencies, and serve as part of treatment plans for some health conditions. 

For example, folic acid supplementation during pregnancy helps prevent birth defects, and adults over 60 may not absorb sufficient B12 and therefore may require a B12 supplement.

Dietary supplements may be particularly helpful for those who cannot consume or absorb certain nutrients well, have higher needs because of a condition or disease state, or are following specific restrictive diets.

For example, people who have had surgery on their ileum (a portion of the small intestine) may not absorb vitamin B12 efficiently and may require supplementation. Similarly, vegans or vegetarians who choose not to eat meat may also benefit from supplemental vitamin B12.

Risks of Dietary Supplements

While dietary supplements can provide various benefits, they also pose potential risks due to the lack of product regulation and improper usage.

Dietary supplements are minimally regulated in the United States, meaning the FDA does not approve them for safety and effectiveness before products are marketed and sold. A supplement manufacturer is only required to notify the FDA if a product contains a completely new ingredient. Even then, the FDA will only review, not approve, the product. This means that the product can go on the shelf without any guarantee of effectiveness and safety. 

Even if it is third-party tested by a reputable organization, this testing only verifies that a supplement contains what it says it contains. Since third-party testing does not test to see if a supplement actually does what it claims to do, even if a supplement is third-party tested, that doesn’t mean that it is necessarily safe and effective for all.

Always speak with a healthcare provider to check whether a supplement is appropriate for your needs and health concerns. It is possible to take too much, to create a nutrient imbalance from improper usage, and for supplements to interact with other supplements or prescribed medications.

Supplement Excess & Toxicity

In a few cases, taking larger than recommended amounts of dietary supplements is dangerous. While it is common to think that you “pee out” excess amounts of vitamins, there are certain vitamins that remain stored in the body, including fat-soluble vitamins such as vitamins A, D, E, and K.

While most side effects of excess vitamins or minerals are mild and easily treatable, excessive amounts of a few types of vitamins or minerals can reach the point of toxicity, where there are potentially dangerous side effects. For example, excessive iron can cause nausea and vomiting, as well as liver damage. Toxicity can be especially troublesome in individuals with errors of metabolism or genetic issues that put them at higher risk of nutrient accumulation. For example, those with hemochromatosis (a disorder where excess iron builds up in the body) are at much higher risk of adverse health effects from too much iron.

It’s important to consider that a number of foods we consume are fortified with vitamins and minerals, and these nutrients contribute to our overall daily intake. For example:

If you consume fortified foods regularly, consider how these products contribute to your overall nutrition needs, as you may be at risk of excess intake should you also add a supplement.

Interactions

Supplements may interact with medications or result in dangerous side effects. For example, vitamin K interferes with a popular blood thinner called Warfarin, reducing the drug's ability to prevent blood clots.

While supplements may sound like “natural” alternatives to medications, they still have the potential to change the chemical activities within your body. Prescription medications have been thoroughly researched and vetted, and prescribing healthcare providers are well-versed in their uses and side effects, while supplements normally do not undergo any such scrutiny. 

 Supplements should not be used as a substitute for prescription medications recommended by your healthcare provider. Even if the manufacturer website makes big promises, this does not mean these claims are supported by research. Supplements are not intended to treat, prevent, or cure diseases. Always speak with a healthcare provider about all of the supplements and medications you are taking or plan to take. This is important if you are taking more than one medication and/or supplement, to understand any risks of supplements and medications interacting with each other.

Other Risks to Keep in Mind

Nutritional needs vary by gender, age, weight, and other factors. For this reason, most supplements are formulated and dosed for specific ages. Always speak with your healthcare provider to ensure that you select the appropriate supplement and dose for your needs. Many supplements have not been tested for safety in pregnant people, children, and nursing parents.

Note that “natural” doesn’t always mean safe. People may assume that because herbal supplements are made from plants, they are completely harmless. Similarly, it is common to assume that a supplement that includes many different ingredients must be beneficial because the more nutrients the better, right? On the contrary, herbal supplements and multi-ingredient supplements can contribute to liver damage and can potentially interfere with medications.

Multivitamins contain a wide variety of vitamins, minerals, and sometimes also include herbal ingredients, so it’s always important to check the supplement facts label and inspect the ingredient list closely to ensure each ingredient is appropriate for you.

What Types of Supplements Does Verywell Health Suggest?

Supplements can be tricky territory, so we do the tough work of weeding through multiple products and brands to present you with a variety of high-quality options based on your values, budget, and preferences. 

We take a food-first approach—if possible, we suggest meeting nutritional needs through foods as close to their original state as possible rather than through supplements. When needs cannot be met through the diet, we may suggest, depending on the scenario and demonstrated needs: individual vitamin and mineral supplements, multivitamins, certain probiotic strains, electrolyte solutions, and macronutrient supplements.

There are many concentrated herbal supplements that contain herbal extracts, where certain parts of the herb are taken from the plant and used to make the supplement, creating a product with a high concentration of certain compounds. As the research on concentrated herbal supplements is sparse and inconclusive, and there are high rates of interactions with other supplements and medications, we will only make suggestions on herbal supplements if and when the research supports it.

Within each of these product categories, we are judicious about what brands and products we support based on various factors (see the attributes explained below), but most importantly, the ingredients used. 

This list will evolve as more research comes to the forefront and new products come to market. Our team will continuously evaluate the safety, validity, and efficacy of supplements and modify our suggestions accordingly.

According to a large-scale study of dietary supplements, the supplements that are most likely to be contaminated with unapproved and potentially dangerous pharmaceutical ingredients are supplements marketed for weight loss, muscle building, or sexual enhancement. This is why we do not support the use of these types of supplements.

It’s important to note that potentially dangerous and poor quality supplements claim to be supported by research. Any company can conduct research strategically to uphold their claims, so it is critical to look at the study design, size, and conflict of interest statement to analyze whether the study is valid.

The type of research that may make the strongest case for supplement efficacy consists of randomized controlled studies. This means that people are randomly assigned to take a specific amount of a supplement or to be part of the control group (not taking the active supplement but instead a neutral ingredient), and researchers look at the differences between the two groups after a certain amount of time. These studies provide strong evidence when they include large groups of people in their trials  and are not conducted by or paid for by any individual or organization with a financial interest in the supplement.

Our Top Priorities When Choosing Supplements

Have you ever walked down the supplement aisle and felt overwhelmed by all of the choices for a simple multivitamin tablet? We certainly have. We aim to do the research for you so you can easily choose what works best for you.

Our team of experienced editors, including an on-staff dietitian, chooses which topics to cover on Verywell Health product round-ups. This team collaborates with dietitian writers to choose the best products in each category, such as vitamin D, protein powders, and multivitamins. We aim to provide you with simple, evidence-based information to help you make an educated buying decision.

Research-Backed Effectiveness & Safety

Our number one priority is to suggest products that have substantial, high-quality research to back their effectiveness and safety. We know how confusing it can be to navigate the supplement world. Manufacturers fill their websites with vague promises of what their supplements will do for your body, like helping you perform at your peak or supporting emotional wellness, weight management, or digestive health. These claims can make us excited to try supplements to feel better and look better, but often these claims are not backed by research.

We carefully comb through the research and don’t suggest supplements with only one study to back them up; we ensure there are a multitude of high-quality studies to support a recommendation. If there is research that makes us skeptical about safety, we will not recommend that product.

Independent Third-Party Tested & Certified

Because nutrition supplements are not well regulated or broadly tested in the United States, selecting a third-party tested product is important to ensure that you’re choosing a safe product. Third-party testing is a control process where an independent lab (one that is not funded by the product company or invested parties) assesses a product to see if it meets certain criteria and standards.

Reliable third-party organizations include NSF, USP, and ConsumerLab. We prioritize products that have been tested and certified by one of these three commonly used organizations, and we will always highlight whether or not each product is third-party tested and certified. 

These certifications can be expensive, so, if a supplement is not third-party tested or certified, it doesn’t automatically mean that it is not a good product. However, these certifications are the only way to feel confident that the labeling of the products is accurate. 

Please note that these third parties do not test for product efficacy, so, just because a product is third-party verified, it does not mean that it is effective. Third-party testing simply helps ensure that a product contains what it says it contains and is not contaminated with other ingredients.

The FDA does regulate what types of claims supplement labels can make. Supplements cannot claim to serve as a treatment, prevention, or cure for any disease. However, they can make three types of claims:

While over-the-counter and prescription medications sold in the USA must be approved by the FDA and are required to meet USP standards, dietary supplements do not require approval before they are marketed. USP standards for dietary supplements are voluntary. A company can market a supplement  without any proof that it is safe, or that it actually provides the benefits they claim it does. Supplements can only be restricted or removed from the marketplace if the FDA proves that they are unsafe—which is often only after harm has already been done.

Other Product Attributes We Value

There are also other attributes we value and seek out when they are relevant to the type of supplement:

It’s important to note that supplements we select do not need to have all of these attributes, but these are values we find important when deciding between various products available on the market. We explain each standard below.

Beyond these standards, it’s important to note that:

Always be sure to read all of the ingredients in your supplement and their quantities, and research the purpose, action, and risks of each ingredient, including potential interactions with other supplements or prescription medications. Like with food, it is usually the case that the shorter and simpler the supplement’s ingredient list, the better.

Non-GMO

When possible, we select products that use non-GMO ingredients. While there is a range of evidence that argues whether genetically modified (also known as “bioengineered”) products are safe or dangerous, we generally choose to suggest products closest to their natural state that are not genetically modified. While the evidence is inconclusive, choosing non-GMO products may be better for your health and the environment.

We also look for the Non-GMO Project Verified certification on product packaging, which means that a product is compliant with the Non-GMO Project’s strict guidelines.

Organic

While some studies show that minimal amounts of chemical residue from non-organic foods are not dangerous to your health, organic products may be safer and healthier than conventionally grown products. For this reason, we work to include and highlight organic options when they are available and relevant.

Minimally Sweetened

Many people are concerned about consuming too much added sugar and choose to replace sugar with low calorie sweeteners and sugar alcohols. However, both artificial low-calorie sweeteners and natural low-calorie sweeteners may have the opposite effect than intended and affect blood sugar control, the gut microbiome, and appetite, and may actually lead to increased food consumption. Sugar alcohols can cause digestive problems such as bloating, gas, and diarrhea. For these reasons, we seek out supplements with minimal added sweeteners in any form.

Additional Considerations When Choosing Supplements

In addition to the quality-focused attributes discussed above, we also consider individual preferences (form, price, availability) and the conditions in which the supplements are made.

Form: Supplements come in a variety of forms, including tablets, capsules, liquid, powder, lozenges, spray, and gummies. We work hard to offer supplement options in a variety of forms to meet your preferences. 

Price: Price is not always reflective of quality. A more expensive supplement doesn’t guarantee a better product. That being said, it may also be prudent to be skeptical of very inexpensive supplements. Some supplements are inherently more expensive to make than others, and the price is mostly dependent on ingredients, volume produced, and certifications obtained. Home-made supplements or tinctures may be affordable and appealing, but ingredients and doses are more difficult to standardize, and quality and shelf life may suffer.

Availability: We select over-the-counter nutritional supplements that are widely available in the United States. While some supplements are only available by prescription or subscription, we include supplements that are in stock at local or online retailers for your convenience.

Quality Control: While there is a lack of quality control on supplement ingredients, safety, and effectiveness, the FDA does have regulations for the supplement manufacturing process. Referred to as GMP (Good Manufacturing Practices) or cGMP (Current Good Manufacturing Practices), these regulations set the requirements for supplement companies to ensure that the supplement is made in a safe, clean laboratory that’s registered with the FDA. We recommend products that are made in GMP facilities.

Summary

The dietary supplement industry can be overwhelming to navigate. To help guide you through, we use research and clinical expertise to weigh the benefits and risks of supplementation and explore top priorities when it comes to choosing supplements to meet your needs. We help you determine if you might benefit from specific supplements and which products may be the best fit. 

Before you start taking any supplements, we always recommend that you discuss the supplements you are planning on taking with a healthcare provider.