The content of this methodology is for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a physician, registered dietitian or other qualified health provider with any question you have regarding dietary supplements, especially if you have any underlying health conditions or are taking any medications. 

Dietary supplements—as the name suggests—are meant to supplement your diet. For most people, taking supplements isn’t essential. But supplements are popular and, in some cases, they can be helpful. Up to three-quarters of Americans take supplements, according to the Council for Responsible Nutrition.

What Is a Supplement?

Supplements come in many forms, such as tablets, capsules, soft gels, powders, gummies, liquids and more. A supplement can be a single nutrient or compound—or a combination of a few of the following:

• Vitamins: These can be individual vitamins (such as vitamin D) and multivitamins. Vitamins are micronutrients that our bodies require to function properly, but they must come from your diet because your body can’t create vitamins on it’s own. Vitamins are compounds and are either water- or fat-soluble. Fat-soluble vitamins (vitamins A, D, E and K) need to be consumed with fat and will accumulate in your body over time. Water-soluble vitamins (vitamin C and all of the B vitamins) are not stored in your body, so any unused vitamins will be eliminated via urine.
• Minerals: Minerals are compounds found in soil and water—and, like vitamins, they must come from your diet. Examples of minerals are calcium, magnesium and iron. These are also available as individual or multiple minerals.
• Herbs or botanicals: Derived from plants (such as ginger or turmeric) or compounds extracted from plants (such as curcumin from turmeric). 
• Probiotics: A strain or strains of live microbes.
• Fatty acids: The building blocks of fats. One of the more common fatty acid supplements is omega-3s.   
• Amino acids and proteins: The building blocks of protein. The supplement BCAAs (branch-chained amino acids), for example, is a trio of amino acids: leucine, isoleucine and valine. Supplements like collagen, soy, etc. contain multiple amino acids but are not considered “complete” proteins, meaning they don’t provide you with all of the essential amino acids you need.  

A supplement can help prevent or correct a nutrient deficiency (think: vitamin D or iron), or insufficiency (such as magnesium or fiber). They can provide additional nutrition support for health issues or chronic conditions, as well as during various life stages, such as pregnancy (we’re looking at you, folic acid) or menopause. Supplements can also help people with restrictive diets due to allergies or personal choice (vegetarian, vegan, etc.).

There’s a catch with supplements, though: They are not regulated the same way food or medications are in the U.S. They technically fall under the oversight of FDA, but the FDA doesn’t verify dietary supplements for safety or efficacy or approve their labeling before they go to market. Instead, it’s the supplement manufacturer’s responsibility to follow FDA’s labeling guidelines, which include whether a supplement contains the ingredients it says it does and in the quantities listed.

That said, not all supplements are worthy of your wariness. There are plenty of vitamins, minerals, protein powders and other supplements on the market that can be safe, effective and have the potential to better your health. And there are supplement manufacturers working diligently to ensure their products are exactly what they say they are. So, how can you decipher the difference between a supplement worth taking and one to skip? We’re here to help. 

Our Search for Dietary Supplements

At EatingWell, part of our mission is to provide science-backed wellness advice to help you—our readers—live your best lives. So, when we recommend a certain supplement, here’s what you can expect from us: 

• We prioritize supplements that are third-party tested and bear the following seals: BSCG certified, INFORMED certified (which includes Informed Sport), NSF Sport, and/or USP Verified. We look to these organizations specifically because their certification means the supplement contains the ingredients named on their label and in the quantity listed. While other third-party labels like USDA Organic or Non-GMO Project Verified also exist on supplement labels, they do not assess the accuracy of the Supplement Facts labels.
• We assess the supplement form (e.g., softgel, powder, gummy, etc.) and ingredient form to ensure they meet the intended need. For example, a magnesium supplement that we recommend for constipation will list a type of magnesium in the ingredient list that has been shown to aid with constipation. This includes filtering out supplements that contain unnecessary ingredients and/or fillers. 
• We review label claims and make sure that they adhere to FDA guidelines and align with available scientific evidence. There are three types of claims that supplement labels can make: health claims (describes a relationship between an ingredient and a lower risk of a health condition, such as “adequate calcium throughout life may reduce the risk of osteoporosis”), nutrient content claims (describes the level of a nutrient in a food, such as “good source of calcium”), and structure/function claims (describes the role of an ingredient or nutrient in maintaining healthy structures or functions in the body, such as “calcium builds strong bones”). 
• We calculate the cost per serving to help in assessing a supplement’s accessibility. 

Our Promise

We will be transparent with how we came to make our recommendations, including why we recommend certain options. We aim to always offer easy-to-understand information about why you may—or may not—need a particular supplement so that you can be empowered to make the healthiest decision for you. 

All of our supplement product recommendations incorporate the expertise of healthcare professionals with specific knowledge of the supplement industry. And all content is closely reviewed by our team of registered dietitians before being published. 

We monitor the market for recalls and new launches and keep our lists updated for safety, accuracy and availability. Though we may occasionally accept free samples for testing purposes, we never promise coverage or let it influence our opinion of a product.