How we review dietary supplements at Yahoo

The dietary supplements market is booming — and shows no signs of slowing down. According to Precedence Research, the global dietary supplements market is expected to nearly double, climbing from $203 billion in 2025 to over $400 billion by 2034. This rapid growth means more choices to suit a wide range of goals and budgets. But it also makes it harder than ever to tease out which supplements are actually safe, effective and worth your hard-earned cash.

Supplements — true to their name — are meant to supplement a balanced diet, helping fill any nutritional gaps that may be difficult for some individuals to meet through food alone. They can play an important role, which is why our nutrition experts review them (carefully!). Still, it's important to acknowledge the industry's potential pitfalls and stress the importance of talking to a health care professional before adding any supplements to your diet — especially if you're pregnant, breastfeeding, taking other medications or managing an illness.

At Yahoo, we're committed to helping you make informed choices about your health and wellness. All of our supplement content is reviewed — and often written — by registered dietitians, bridging the gap between scientific research and everyday decisions with expert-backed, evidence-based insights. We also know that real-world experience matters. That's why we dig through online reviews and, whenever possible, test products ourselves.

Here's a deep dive into why we take supplement content so seriously — and how we choose the products we recommend.

What are dietary supplements?

According to the Food and Drug Administration, a dietary supplement is a product taken by mouth and intended to supplement ingredients that are either missing or inadequate in your diet, such as vitamins or minerals. You'll usually find these products in the form of capsules, softgels, tablets, liquids or powders. They must be labeled as a "dietary supplement" on the front of the bottle, and the full label must also include a "Supplement Facts" panel outlining the serving size and amount of each dietary ingredient.

Supplements are often marketed with specific health claims — like "boosts immune health" or "promotes restful sleep" — to describe how the ingredient affects the body. However, supplements are not permitted to claim diagnosis, treatment, cure or prevention of disease. If these types of claims are made, the label must also carry a mandatory disclaimer explaining that these statements have not been evaluated by the FDA.

Some supplements contain just one active ingredient, while others combine multiple, such as:

• Vitamins (for example, vitamin D, vitamin B12, folic acid)

• Minerals (calcium, magnesium, iron)

• Herbs or botanicals (ginseng, chamomile, black cohosh)

• Amino acids and proteins (creatine, collagen, leucine)

• Fiber and prebiotics (psyllium husk, inulin, wheat dextrin)

• Antioxidants (CoQ10, resveratrol, lutein)

It's important to emphasize that while supplements may contain health-supportive messaging, these products are not intended to replace medical treatment, nor should they be used as the sole approach to diagnose or manage disease.

Potential safety concerns

When it comes to dietary supplements, it's important to remember that they are not guaranteed to be safe or effective — and that the supplement industry often operates like the Wild West, with serious implications.

Unlike prescription or over-the-counter medications, dietary supplements do not require approval by the FDA for safety or effectiveness before they reach the market. This means products can be sold without solid proof that they work — and, in some cases, without actually containing the types or amounts of ingredients listed on the label. The risks can range from mild to severe: On one end, you might take a supplement that simply doesn't deliver the intended benefit or is slightly underdosed. On the other end, you could unknowingly ingest toxic levels of certain nutrients or unlisted, potentially unsafe ingredients.

That's why it's essential to choose supplements from reputable brands that test their products throughout the manufacturing process. This helps ensure the final product contains exactly what's listed on the label — in terms of both ingredient types and their amounts — and nothing extra. These purity and potency tests also screen for contaminants such as heavy metals.

While some supplement companies offer little to no transparency about their testing, others provide more assurance by one of two methods:

• Using third-party laboratories to verify their product quality

• Conducting in-house testing through certified labs that are regularly audited to maintain strict safety and quality standards

The gold standard, however, is third-party certification from trusted organizations, such as:

Choosing supplements that carry these seals can give you more confidence in their quality, purity and accuracy — providing you with an added layer of trust.

Also keep in mind that supplements aren't always safe or appropriate for everyone — especially children, people who are pregnant or breastfeeding or those with certain chronic conditions. Some ingredients, particularly herbs, can also interact with medications, potentially causing harmful effects.

Because of these risks, it's essential to consult a trusted health care professional — such as your primary care provider or a registered dietitian — before starting any new supplement. They can help you determine whether the ingredients and dosages are safe and appropriate for your specific needs.

How we review supplements

When it comes to research on dietary supplements, we won't sugarcoat it: It's a tricky space. After all, many factors influence health, and what works for one group might not work for another. That's where we come in. Our mission is to cut through the noise and highlight products with genuine scientific support, not just marketing hype.

For example, while ingredients like zinc and magnesium are well researched for addressing deficiencies, that doesn't mean every product containing them is effective, especially if the dosages or formulations differ from those studied. We feature products backed by solid evidence, and we're always up front when more research is needed.

Before any Yahoo supplement review reaches your feed, it's thoroughly vetted by a registered dietitian and evaluated against the following criteria:

• Evidence-based ingredients: Even if there's no research on the specific product, we examine whether its individual ingredients are supported by high-quality studies. For multi-ingredient formulas, we also assess how those ingredients interact — whether they've been shown to work well together or, in some cases, interfere with one another.

• Dosage and bioavailability: We scrutinize dosage levels, evaluating them for safety and effectiveness, noting when nutrients are present in forms that are easier for the body to absorb.

• Label transparency: We look for clear labeling of all ingredient types and amounts, and we're cautious of products with proprietary blends that obscure exact quantities.

• Third-party testing: We prioritize products that have undergone credible third-party testing for purity and potency by organizations like NSF and USP.

• Health claims: We approach product claims with a healthy dose of skepticism, seeking to substantiate any health claims with high-quality, independent research — prioritizing peer-reviewed, double-blind, well-controlled studies.

• Safety concerns: We consider potential safety risks and side effects, evaluating whether a product is appropriate — or a no-go — for certain populations.

We also favor products that are non-GMO, organic, have short ingredient lists, are low in added sugars and avoid unnecessary additives or fillers. Within each category, we may highlight options that meet specific dietary needs — for example, vegan or gluten-free — recognizing how important these factors are to many individuals.

Our approach to testing

Expert approval matters, but so does personal experience. A supplement should not only meet high standards of safety and efficacy, but also be something you can realistically take on a regular basis.

That's why, once a registered dietitian has fully reviewed a product's ingredients and claims, we take a purposeful approach to testing — making sure it's evaluated by someone representative of the target demographic. For example, prenatal vitamins are tested by someone who is pregnant or breastfeeding, and men's multivitamins are tested by men.

We're also realistic about what we can and can't measure. Everyone's body responds differently, so the benefits — or side effects — our testers experience may not mirror your own. While we aim to offer valuable expert insights, we can't guarantee the same results for every individual.

In addition to sharing their overall impressions, testers complete detailed questionnaires addressing:

• Form: Is it easy to take?

• Directions: Were the instructions clear and easy to follow?

• Taste: How did it taste? Any lingering aftertaste?

• Side effects: Was it easy to tolerate?

• Value: How does it compare in quality and price to similar products?

• Recommendation: Would they continue taking it or purchase it again?

Continuous review process

The supplement space evolves rapidly — from new research and formulation changes to recalls and price changes. Our team of health experts stays on top of these shifts and makes updates to our supplement content as needed. When an article is refreshed, you'll find an "Update" note at the end of the introduction, indicating the date and summarizing any notable changes.

Our editorial standards

We understand how important supplements can be for your health — and the risks that come with them. That's why we pair expert guidance with real tester feedback and uphold strict editorial standards. While testers may occasionally receive products for free from the brands they're reviewing, all opinions and evaluations are entirely independent. Read more about our editorial standards and review process for health products.

Our health content is for informational purposes only and is not intended as professional medical advice. Consult a medical professional on questions about your health.