A testimonial tells you what one person says happened to them. A seller promise tells you what the company wants you to believe. A human study tells you what was measured in a defined group of people under defined conditions. For a brain or wellness supplement, a well-run human study of the finished product is the only one of the three that can begin to show whether the product does what the ad says, and only if you can see how the study was done. The claim log below helps you sort what you are reading, one claim at a time.
TotalHealth Research Desk is an independent editorial publication. The “RD” in our name stands for Research Desk, not Registered Dietitian, and this article is general education, not medical advice. Our medical disclaimer explains the limits.
The Short Answer: Three Kinds of Statements
- A personal story (testimonial). It may be sincere. The NIH Office of Dietary Supplements states that testimonials from people who say they tried a product are not evidence based and usually cannot be corroborated. A story cannot show what would have happened without the product.
- A seller promise (marketing claim). This is the company describing its own product. It is an assertion that still needs support, and the FTC's health products guidance says advertisers must have appropriate scientific evidence behind the claims their ads make or imply.
- A human study. The FTC guidance describes randomized, controlled human clinical trials as the most reliable form of evidence and generally the type experts would require. It also says the quality of the research matters more than the quantity.
Why a Convincing Story Is Not the Same as Proof
Nothing here says personal stories are fake. People can feel better, and they can honestly credit a product for it. The issue is what a story can and cannot show. It has no comparison group, it cannot say whether anything else in the person's life changed at the same time, and you usually cannot check the details. The FTC guidance adds that testimonials showing results more dramatic than users can generally expect are likely to be deceptive unless the ad clearly discloses what typical users should expect.
The FTC guidance also says that animal and lab (in vitro) studies alone are not enough to back a health claim in people, and that studies showing an association do not prove cause and effect. That matters for brain supplements, because an ad can cite research on a single ingredient, or on cells or animals, while describing the finished product as if it had been tested.
The Three-Part Claim Log
Copy the claim exactly as written on the product page or ad. Then fill in the source type and what independent evidence would need to measure. If you cannot find a detail, write Unknown. An unknown is useful information; do not fill it in with a guess.
Each entry has three parts: the exact advertised result, the source type, and what independent evidence would need to measure.
- Blank entry to copy
- Exact advertised result: the words used, in quotation marks, and the page or ad where you found them.
- Source type: personal story, seller promise, ingredient-only study, study of the finished product, or Unknown.
- What independent evidence would need to measure: the outcome named in the claim, in the kind of people the claim is aimed at, compared with a control group, for the length of time stated.
- Practice example (hypothetical wording, not from any real product)
- Exact advertised result: “Sharper memory in two weeks.”
- Source type: seller promise.
- What independent evidence would need to measure: a defined memory test given before and after, in a randomized group taking the product and a control group not taking it, over at least the two weeks claimed. Unknown until you find a study that did this.
- Practice example (hypothetical wording)
- Exact advertised result: “I felt clearer after the first bottle.”
- Source type: personal story.
- What independent evidence would need to measure: the same outcome in a comparison group. The story alone does not say what else changed, so whether the product caused the change is Unknown.
- Practice example (hypothetical wording)
- Exact advertised result: “Contains an ingredient shown in studies to support focus.”
- Source type: seller promise citing ingredient research.
- What independent evidence would need to measure: whether the studies were in humans, used the same amount of that ingredient found in the product, and tested the finished product. If the label does not list amounts, the dose is Unknown.
Questions That Help You Fill In the Third Part
- Were the participants people, or animals or cells? The FTC says animal and lab studies alone are insufficient.
- Was there a control group, random assignment, and blinding? The FTC lists these among the features of a valid trial.
- Does the result match the claim? The FTC points to clinically meaningful outcomes and statistically significant results. As an everyday example, a change in a lab number is not the same as a change in memory in daily life.
- Was the study of this product, at this dose? If the ad does not link a study, or the study details are missing, write Unknown.
- Who can you check it with? The NIH Office of Dietary Supplements suggests asking who runs the site, what the original source is, how the site documents its evidence, who reviewed the information, and how current it is.
What This Looks Like on a Review Page
Our IQ Honey review is one example of setting a brain supplement's advertised claims against its label and the research on its ingredients. It includes sections on the proprietary blend, the inconsistent ingredient lists, the refund guarantee, and what research says about the ingredients. It is a single-product review, so use it as a model for your own log rather than as a verdict on any other product.
Limits of This Checklist
- It helps you spot what is missing. It cannot tell you whether a supplement is safe for you.
- A well-designed trial of one product does not automatically apply to a different product, dose, or group of people.
- A study listed on a product page does not mean it supports the claim next to it. Open it and check.
Who Should Talk to a Professional First
Ask a pharmacist or physician before starting a brain or wellness supplement if you take prescription medicines, have a medical condition, are pregnant or nursing, or are planning surgery. Our cognitive supplement safety guide covers interaction questions for several botanical ingredients. If you or someone close to you notices ongoing or worsening memory or thinking changes, that is worth discussing with a clinician rather than trying to solve with a product.
What to Do Next
- Pick one supplement you are considering and copy its three biggest claims into the log, word for word.
- Label the source type for each, writing Unknown wherever you cannot find a study.
- Look for the study itself, not a summary of it, and compare it against the questions above.
- Bring the log and the product label to your pharmacist or doctor.
- If the log is mostly Unknown, the evidence is not yet visible to you. That is a reason to wait and ask questions, not a reason to buy.
Sources
Both sources below were opened for this article on October 1, 2026.
- NIH Office of Dietary Supplements, How To Evaluate Health Information on the Internet: Questions and Answers (page lists a review date of May 4, 2022). Used for the testimonial statement and the evaluation questions.
- Federal Trade Commission, Health Products Compliance Guidance (dated December 20, 2022). Used for the evidence standard, randomized controlled trials, animal and lab studies, association versus causation, and testimonial disclosure.