Advocates on AgingSupplement Guide
Two things worth knowing before you add a supplement: whether an independent lab has confirmed the contents match the label, and whether it interacts with the medications you already take. This page covers both.
Third-party verification, and what it actually proves
The FDA does not approve supplements before they're sold
Under a 1994 law, supplements are regulated more like food than like medication. The FDA does not review them for safety or effectiveness before they reach shelves. Manufacturers are responsible for their own quality control, and the agency generally steps in only after a problem surfaces — across a market that has grown from roughly 4,000 products to well over 80,000.
Independent testing has repeatedly found products containing more or less of an ingredient than the label claims, ingredients that aren't listed at all, or contaminants that shouldn't be there.
What the independent certifiers actually check
These are the marks worth looking for on any brand, not just Thorne:
The most rigorous general-purpose mark. Annual facility audits plus ongoing testing for identity, potency, and purity.
Every batch screened for 280+ substances banned in sport, plus label accuracy and contamination. The broadest contaminant screening.
Run by the LGC Group analytical lab. Every batch tested before it ships.
A testing publication rather than a certification — buys products at retail and publishes pass/fail results.
Why We Point People to Thorne
Thorne carries four independent certifications, not one
Most people know Thorne for the NSF Certified for Sport mark, but that's the most visible of four. Two verify the product itself; two verify the facility that makes it. That distinction matters, because a clean test on one batch tells you less than a standard the whole operation is held to.
- NSF Certified for Sport® — batch-by-batch testing for 280+ substances banned in sport, on 40+ Thorne products. Product-level.
- TGA Certified (Australia) — an A rating from what's widely considered the world's strictest supplement regulator. Thorne says it was the first U.S. supplement company fully certified. Facility-level.
- GRMA / NSF-ANSI 455-2 — an independent audit standard written specifically for supplement manufacturing, above the legal minimum. Facility-level.
- cGMP compliance record — Thorne reports passing every FDA inspection of its facility, warehouses, and shipping centers without a Form 483 being issued. Regulatory.
A closer look at what each certification actually verifies →
Sign up through us and save 15%
Creating your Thorne account through our link applies a standing 15% discount to everything you order — not just a first purchase — and your orders ship free.
Get 15% off at ThornePractitioner affiliate disclosure: Advocates on Aging earns a commission on orders placed through this link, at no additional cost to you. We recommend Thorne for its third-party testing and certification record, not because of the commission. Nothing on this page is a recommendation that you take a supplement; it is general education. Talk with your physician or pharmacist before starting anything new.
Thorne is not your only option. Other brands that carry these same certifications →
Questions about a specific supplement?
Whether it's something in the checker above or something you came across elsewhere, we're happy to help you make sense of it — how to read a label, what a certification mark actually means, or how to compare two products.
Contact UsWant guidance tailored to your situation?
Leslie Stashevsky offers holistic nutrition guidance for aging adults and the family members caring for them, including general supplement education.
Nutrition GuidanceOther brands that carry these certifications
Thorne holds the certifications described above, and it isn't the only brand that does. If it's easier to pick something up at Costco, Target, or a regular pharmacy, these brands also appear in the certifiers' own public directories. What matters is that whatever you buy has been independently verified.
Read the bottle, not the brand. Both programs certify individual products, not whole companies. A brand can have one certified product and a dozen that aren't. The mark has to be on the specific bottle in your hand — so check the label, or look the product up in the directories linked below.
USP Verified
Brands whose manufacturers participate in USP's Dietary Supplement Verification Program:
- Nature Made — the widest range of USP Verified products on a drugstore shelf
- Ritual
- Natrol
- Natural Factors
- Schiff (Move Free, Airborne)
- Youtheory
- Various store and private-label brands, including warehouse-club lines, made by USP-participating manufacturers
NSF Certified for Sport®
Brands listed in NSF's public certified-product directory. The screening is built for athletes, but the contaminant testing benefits everyone:
- Thorne
- Klean Athlete
- Nordic Naturals — widely used for fish oil
- Nature Made — carries both marks
- Garden of Life
- MegaFood
- Designs for Health
- Nutramax (Cosamin, Denamarin)
- Vital Proteins, Optimum Nutrition, Sports Research
Check your medications against common supplements
Select what you take on both sides. The checker reports well-documented interactions between them — including a few that are helpful rather than harmful, since those are worth knowing too.
This list is not all-inclusive. The medications and supplements above are common ones, not every one that exists. Plenty of real interactions are not captured here, and a supplement can affect your health in ways that have nothing to do with an interaction — through a health condition you have, a procedure you're scheduled for, or your kidney and liver function.
Talk with your physician or pharmacist if: the checker flags something, your medication or supplement isn't on either list, you're pregnant or nursing, you have kidney or liver disease, or you have surgery coming up. A pharmacist will review your full medication list for free, and that review is more thorough than anything a web page can do.
Never stop, start, or change the dose of a prescribed medication based on what you read here.
Medical disclaimer: This page is general education, not medical advice, and is not a recommendation to take any specific supplement. Nothing here is intended to diagnose, treat, cure, or prevent any disease. Supplements can interact with medications, affect existing health conditions, and are not appropriate for everyone. Always verify any supplement with a physician or pharmacist to determine whether it's appropriate for you, at what dose, and whether it's safe alongside your current medications and health conditions before starting it. The interaction checker covers a curated list of well-known interactions only and is not a substitute for a full medication review with a physician or pharmacist.