Biomarker testing for supplement brands: what to measure and what you can claim
More supplement and DTC wellness brands are adding lab tests to their product lines. The logic is easy to follow: a customer who sees their own numbers has a reason to start, and a retest a few months later gives them a reason to come back.
The hard part isn't the kit. It's deciding which biomarkers belong in the program, how results connect to your products, and what your marketing can say once lab data is involved. Get those right and testing builds trust. Get them wrong and it can create regulatory risk and unhappy customers.
Here's a practical framework for brands planning a testing program.
Start with the question a test can actually answer
A good biomarker program begins with what a result can tell a customer, not with the longest panel you can buy. For each marker, ask three things:
Is there an established reference range or clinical threshold the lab can report against?
Does the marker change on a time scale that makes a retest meaningful?
Would a reasonable customer understand what an out-of-range result means and what to do next?
Markers that pass all three usually make a stronger program than a panel of 40 analytes that nobody can interpret.
Choosing biomarkers for a supplement program
Common categories for supplement brands include micronutrients (such as vitamin D, B12 and iron studies), omega-3 status, lipids and glucose markers, inflammation markers such as CRP, and hormones. Each comes with its own caveats.
Vitamin D is popular, and guidance has shifted
Vitamin D is often the first test a brand considers. It's worth knowing that the Endocrine Society's 2024 guideline on vitamin D for the prevention of disease suggests against routine 25-hydroxyvitamin D [25(OH)D] testing in generally healthy adults who don't have an established reason for testing. The panel found that levels providing outcome-specific benefits haven't been established in clinical trials.
That doesn't make vitamin D testing off-limits. It does mean your copy shouldn't imply that a result tells someone exactly how much to supplement for better health outcomes. The NIH Office of Dietary Supplements describes serum 25(OH)D as the best indicator of vitamin D status and explains the ranges it uses, which is a useful, neutral reference for your results content.
Match the marker to the product, honestly
If you sell an iron supplement, iron studies are a natural fit. If you sell a general multivitamin, a broad "nutrient score" may promise more than the science supports. Tie each marker to a clear educational purpose, and let the customer's clinician, not the product page, guide treatment decisions.
Watch for supplements that interfere with lab tests
This is the issue many brands overlook. The FDA has warned that biotin, often found in dietary supplements, can significantly interfere with certain lab tests and cause incorrect results that may go undetected. The agency's biggest concern is falsely low results on troponin, a marker used to help diagnose heart attacks, but the warning applies to certain other lab tests as well.
FDA also notes that since its first safety communication in 2017, some test developers have reduced biotin interference in their assays and others haven't. In practice, that means the risk depends on which assay your lab runs, and it's worth asking rather than assuming.
If your line includes hair, skin and nail products or high-dose B-complex formulas, build this into your program:
Ask customers about biotin and multivitamin use at ordering.
Put a clear note in the kit instructions.
Ask your lab partner which of its assays are susceptible to biotin and how it handles that risk.
Know where the claims line sits
Adding lab tests to a product line doesn't change the rules for supplement marketing. It often makes them easier to break by accident.
FDA: structure/function, not disease
Under the Dietary Supplement Health and Education Act (DSHEA), supplements can carry structure/function claims, such as "calcium builds strong bones." These claims aren't pre-approved by FDA. The manufacturer must have substantiation, notify FDA within 30 days of marketing the claim, and include the disclaimer that the product isn't intended to diagnose, treat, cure or prevent any disease.
A results page that says "your low vitamin D puts you at risk of disease, and our product fixes it" turns a structure/function claim into a disease claim. Keep test education and product claims clearly separated.
FTC: substantiation for every implied claim
The FTC's Health Products Compliance Guidance replaced its 1998 supplement advertising guide and applies to diagnostic tests and health apps as well as supplements. A few points matter most for testing programs:
Health claims need "competent and reliable scientific evidence," which generally means randomized, controlled human clinical trials.
Marketers are responsible for implied claims, judged by the "net impression" of the whole ad, including images and product names.
The DSHEA disclaimer won't cure an otherwise deceptive ad.
Customer testimonials and surveys are never enough to substantiate a health benefit.
The guidance also gives an example that fits testing programs closely: if a supplement addresses a deficiency that only a small share of the target audience actually has, the claim should be limited so customers understand who is likely to benefit. A test can help show who that is, but only if your messaging stays honest when most results come back normal.
Build the clinical and lab plumbing first
Behind every branded kit sits a regulated process. Before launch, confirm:
Who orders the test. Under CLIA, labs may only test at the request of an authorized person, as defined by state law. Most DTC programs use a physician network for ordering and review.
How abnormal and critical results are handled. Decide who contacts the customer, how quickly, and what they're told.
Where you can sell. Some states, such as New York, require their own clinical laboratory permit for labs testing specimens collected there.
Whether each test is validated for home collection. A marker validated on a venous draw may behave differently in a finger-prick or dried blood spot sample.
Our earlier guide on questions to ask a white-label lab testing partner covers these checks in more detail.
Design results that keep customers engaged
Retention comes from results customers can understand and act on. A few practices help:
Show the reference range next to each result, plus a plain-language explanation of what the marker measures.
Separate "what your result means" from "products you might consider," and avoid implying that a product will change a specific number unless you have evidence for that.
Schedule retests at intervals that match how quickly a marker can change, rather than on a fixed marketing calendar.
Let customers compare their own results over time. A trend is usually more meaningful than a single snapshot.
Bringing it together
A testing program can make a supplement brand more personal and more credible, but only if the science, the claims and the lab operations line up. Pick markers you can explain, plan for interference, keep product claims inside the FDA and FTC lines, and choose a CLIA-certified lab that can support your brand behind the scenes.
If you're mapping out a program, our overview of lab testing for supplement brands shows how IHDLab supports white-label test kits from the box to the results.
This article is for educational purposes and isn't legal or medical advice. Talk with regulatory counsel about your specific claims.
