Supplements and Products

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Supplements and Products

What the peer-reviewed evidence supports about common supplements and health products, and how to evaluate claims critically.

Overview

What you need to know

The global dietary supplement market is valued at over $150 billion and is one of the most poorly regulated consumer product categories. In the United States, dietary supplements are regulated as food, not as drugs, meaning manufacturers do not need to prove safety or efficacy before selling a product. The burden of proof falls on the FDA to demonstrate harm after the fact.

This regulatory gap, combined with aggressive marketing and a large body of industry-funded research, makes it genuinely difficult to know what the evidence supports. This resource does not provide supplement recommendations. It explains how to evaluate claims, what the regulatory framework looks like, and what the peer-reviewed research shows for commonly used ingredients.

Key Concepts

What the evidence shows

01

Structure-Function Claims vs. Health Claims

The FDA distinguishes between two types of label claims. Structure-function claims describe how a product affects the body’s structure or function, such as ‘supports immune health,’ and do not require FDA authorization. Health claims assert a relationship between a nutrient and a disease and require FDA review. Most supplement marketing uses structure-function claims, which have a very low legal bar.

02

Third-Party Testing

Because the FDA does not verify supplement label claims before products reach market, independent testing organizations such as NSF International, USP, and Informed Sport test products to verify that they contain what the label claims, in the amounts stated, without contaminants or prohibited substances. Third-party certification is one of the strongest available quality signals.

03

The Evidence Hierarchy

Not all research is equal. The strongest evidence for supplement efficacy comes from randomized controlled trials and systematic reviews of those trials. Mechanistic studies, cell culture research, and animal studies generate hypotheses but do not establish efficacy in humans. Marketing frequently cites preliminary research as evidence that a supplement works. Evaluating the type and quality of evidence is essential.

04

Creatine Monohydrate

Creatine is one of the most extensively studied supplements with over 700 published studies. Evidence consistently supports its efficacy for improving strength, power output, muscle mass, and high-intensity exercise performance. There is also emerging evidence for cognitive benefits, particularly in older adults. Creatine monohydrate is the most studied and cost-effective form. Safety at recommended doses is well established.

05

The Problem With Proprietary Blends

Proprietary blends list ingredients without specifying individual amounts, making it impossible to determine whether any ingredient is present at a dose supported by the research. A supplement with a proprietary blend containing ten ingredients may have nine of them at doses too low to produce any effect.

Professional and Government Guidelines

What the major bodies recommend

These guidelines and standards represent the current consensus of the relevant professional and government bodies.

U.S. Food and Drug Administration (FDA)

Dietary supplements are regulated under the Dietary Supplement Health and Education Act (DSHEA) of 1994. Manufacturers are responsible for ensuring their products are safe and claims are truthful, but they are not required to register products with the FDA or get FDA approval before producing or selling supplements.

Federal Trade Commission (FTC)

The FTC enforces truth-in-advertising requirements for supplement marketing. Health claims must be substantiated by competent and reliable scientific evidence. The FTC has taken enforcement action against numerous companies for deceptive advertising claims.

NIH Office of Dietary Supplements (ODS)

The NIH Office of Dietary Supplements maintains evidence-based fact sheets on individual supplement ingredients, summarizing research on safety, efficacy, and drug interactions. These fact sheets are one of the most reliable public sources for evaluating supplement claims.

NSF International and Consumer Lab

Independent testing organizations document significant discrepancies between what labels claim and what products contain, including less than the claimed amount of active ingredient, heavy metal contamination, and presence of undisclosed pharmaceutical compounds. Third-party certification substantially reduces these risks.

In Practice

What this means for you

Before purchasing any supplement, ask four questions. Is there human clinical trial evidence for this ingredient at this dose? Has this specific product been third-party tested? What does the NIH Office of Dietary Supplements say about this ingredient? Does the benefit, if real, justify the cost relative to the dietary and lifestyle changes that produce equivalent or larger effects?

For most people, the evidence supports a short list of supplements worth considering: creatine monohydrate for muscle and cognitive function, vitamin D if you are deficient, and omega-3 fatty acids if dietary intake from fish is low. Everything else requires careful individual evaluation of the evidence.

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Authoritative External Sources

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