Structure/Function Claims: What Evidence Do Supplement Brands Need?

“Supports restful sleep” sounds straightforward. Deciding whether your product has the evidence to support that statement takes more work.

For supplement brands and ingredient manufacturers, two questions need separate answers: is the proposed wording an appropriate structure/function claim, and does the research support what it communicates?

A structure/function claim needs substantiation before it is used. Choosing familiar wording, adding a disclaimer or conducting a study does not automatically make a claim acceptable. FDA identifies substantiation, notification and a required labeling disclaimer as core requirements for these dietary supplement claims. FDA compliance guide

This guide explains the U.S. framework and offers a practical process for planning and reviewing evidence. It is educational information, not a product-specific legal determination.

What is a structure/function claim?

A structure/function claim describes how a nutrient or dietary ingredient affects the body’s normal structure or function. FDA gives “calcium builds strong bones” as an example.

These claims differ from statements that a product diagnoses, treats, cures or prevents disease. Structure/function claims are not preapproved by FDA, but they still require evidence that they are truthful and not misleading. FDA: Structure/Function Claims

The distinction depends on the complete message, not just a particular verb. Disease-risk-reduction health claims follow a separate FDA framework and are not structure/function claims. FDA overview of label claim categories

How is a structure/function claim different from a disease claim?

A statement about supporting normal function is different from a statement about treating a disease.

The following examples illustrate the distinction. They are not approved wording for any particular product.

These examples depend on the full context and supporting evidence. Sleep wording can imply a disease claim when paired with insomnia-related messaging. They are not universally compliant phrases.

Adding “supports” does not resolve a disease implication elsewhere on the page. Product names, images, symptoms and surrounding language can affect how a claim is understood. FDA’s guidance addresses both explicit and implied disease claims. FDA compliance guide

For a brand reviewing a campaign, the practical task is to assess the whole presentation: packaging, product page, advertising and any testimonials used alongside the claim.

What evidence do structure/function claims need?

There is no universal study package that substantiates every structure/function claim.

FDA recommends considering the meaning of the claim, how closely the research relates to it, the quality of the evidence and the totality of the available findings. Its guidance does not provide a fixed formula for the number or type of studies required. FDA substantiation guidance

For health benefit advertising, FTC guidance generally expects high-quality randomized, controlled human clinical testing. Observational findings can identify associations, but they do not establish causation. FTC Health Products Compliance Guidance

Improvement from baseline alone does not establish benefit versus a control. Assess the prespecified comparison, effect size, uncertainty and whether the difference matters to participants. The analysis should account for multiple testing rather than selecting only favorable outcomes. A statistically significant finding is not automatically a meaningful benefit. FTC guidance on interpreting clinical evidence

A useful starting point is an evidence review organized around the exact proposed claim.

Use this table as a discussion tool for your scientific and regulatory reviewers, rather than as a pass-or-fail compliance test.

Can an ingredient study support your finished product?

Ingredient research may be relevant, but its applicability needs to be evaluated.

A study on one extract, dose or formulation should not automatically be treated as evidence for every product carrying the same ingredient name. FDA recommends examining whether the studied material and conditions of use are relevant to the marketed supplement. FDA substantiation guidance

When reviewing a supplier’s research package, ask for:

• The full study report or publication.
• Specifications for the material tested.
• Dose, formulation and administration details.
• Participant characteristics.
• The planned outcomes and analysis.
• Findings that did not support the research hypothesis.
• An explanation of any differences from your finished product.

If those details are missing, record the gap. Do not fill it with assumptions. Review safety information relevant to the proposed dose, population and conditions of use alongside benefit evidence. An absence of observed adverse events does not establish that a product is safe.

How should you plan a study around a proposed claim?

Start by translating the proposed benefit into a question that a protocol can assess.

For a sleep product, ask what “better sleep” is intended to mean. Is the focus perceived sleep quality, time to fall asleep, sleep duration or daytime functioning?

Then ask the research team to explain:

1. The main outcome: What is the study primarily designed to assess?
2. The population: Whose experience is relevant to the research question?
3. The comparison: How will the design help distinguish a product effect from other explanations?
4. The measurements: Which assessments address the question?
5. The timing: When will measurements be collected?
6. The analysis: How will missing observations, dropouts and deviations be handled?
7. The limitations: What conclusions would remain outside the study’s scope?

Depending on the protocol, measurements may combine wearables, participant questionnaires, laboratory assessments and other appropriate tools.

Our clinical research methodology and evidence page explains how these decisions fit together.

If you are commissioning ingredient research, our clinical studies for ingredient manufacturers buyer’s guide explains how to compare study designs, research partners, budgets and deliverables.

Are wearable measurements enough?

A wearable measurement is one source of information. Its usefulness depends on the research question and the study design.

Before including a wearable outcome, ask the team to explain why the device and metric are suitable for the intended use. Also ask how recordings will be checked, how missing nights will be handled and whether software or device differences could affect interpretation.

Device-derived sleep estimates are not automatically equivalent to polysomnography, a laboratory sleep assessment, or to a participant’s experience of sleep. Validation needs to fit the particular metric, population and intended use. Questionnaires and laboratory assessments provide complementary information; they do not automatically confirm wearable findings.

For a sleep study, a planning discussion might distinguish:

FDA’s digital health technology guidance discusses selecting and evaluating remote measurement tools in medical-product investigations. It is a useful reference, although its applicability to a particular supplement study should be assessed. FDA digital health technology guidance

For further reading, see our guide to wearables in decentralized clinical trials.

Does a disclaimer make a claim acceptable?

No. A disclaimer does not supply missing evidence or neutralize a contradictory benefit claim.

FTC guidance explains that disclosures cannot correct an otherwise misleading advertising message simply by contradicting it. FTC Health Products Compliance Guidance

Dietary supplement labeling with structure/function claims must include the prescribed FDA disclaimer and meet the applicable presentation requirements. Use the official requirements when reviewing the wording and placement rather than copying another brand’s label. FDA dietary supplement labeling guide

The dietary supplement labeling disclaimer and FTC advertising disclosures are separate requirements. The labeling disclaimer is not automatically required in every advertisement. A website may function as labeling as well as advertising, depending on context, so have the applicable requirements assessed for each use. FTC guidance on labeling and advertising

Treat evidence review and labeling review as separate tasks. Completing one does not complete the other.

Do you need to notify FDA?

For covered structure/function and related dietary supplement labeling claims, the responsible person or firm must notify FDA no later than 30 days after first marketing the supplement with the claim.

FDA provides instructions for the notification and the information it must contain. The notification process is not premarket approval of the claim. FDA notification guidance, FDA claims overview

Assign responsibility for this step before launch and retain the submission records with the claim documentation.

A hypothetical example: reviewing a sleep claim

Imagine a brand wants to use “supports restful sleep” for a new supplement.

The team has an ingredient study, customer feedback and wearable recordings from an exploratory project. Before deciding whether to use the claim, it could work through the following process:

1. Define the intended message. What benefit would a customer reasonably expect?
2. Inventory the evidence. Obtain the complete materials, not only a supplier’s summary slide.
3. Compare the products. Document differences between the study material and the finished supplement.
4. Review the outcomes. Identify which findings address the proposed benefit.
5. Record the limitations. List unresolved questions about design, participants, measurements and analysis.
6. Seek a claim-specific assessment. Have qualified scientific and regulatory reviewers assess the proposed wording and its presentation.

The result might be to commission additional research, revise the proposed claim or postpone using it. This example does not establish that the hypothetical evidence is sufficient.

What should you keep in a claim substantiation file?

A practical internal file should let someone understand why a claim was selected and what supports it.

Consider including:

• Exact claim wording and where it will appear.
• Dated copies of relevant packaging and marketing materials.
• Product specifications and conditions of use.
• An evidence summary linked to full reports.
• Scientific review notes and identified limitations.
• Regulatory review comments.
• Required notification records.
• A named owner and review date.

Keep track of revisions. If the formula, dose, intended audience or marketing message changes, flag the claim for reassessment.

Frequently asked questions

Does “clinically studied” mean the benefit is established?

No. Saying a product was studied does not explain whether the study supports the advertised benefit. The wording and surrounding presentation must accurately reflect the evidence. FTC Health Products Compliance Guidance

Is one study always enough?

There is no universal number. FDA recommends assessing the quality, relevance and totality of the evidence rather than relying on a study count alone. FDA substantiation guidance

Does FDA notification mean the claim is approved?

No. Structure/function claims are not preapproved by FDA. A notification should not be described as FDA endorsement. FDA claims overview

Can customer testimonials replace clinical evidence?

No. Testimonials do not substitute for substantiation of the objective benefit claims they communicate. FTC Health Products Compliance Guidance

Plan the evidence before finalizing the claim

Before commissioning research, bring the proposed wording, product specifications and existing evidence to the discussion.

Ask what the study could answer, what it could not answer and how the findings would be evaluated before they appear in marketing.

Explore the Reputable Health clinical research platform and our research methodology to prepare for that conversation. For related regulatory context, read our guide to FDA approval for wellness products.