How to check if a supplement is third-party tested

The US Food and Drug Administration states it plainly: under the 1994 Dietary Supplement Health and Education Act, FDA does not have the authority to approve dietary supplements before they are marketed, and the firm that makes or distributes a supplement is responsible for making sure it is not adulterated or misbranded. FDA's role is mostly enforcement after a product is on sale.

Independent certification fills part of that gap. A certifier tests products against a standard and publishes a list of those that pass. NSF describes its NSF/ANSI 173 standard as an independent testing standard and certification program for dietary supplements, and says its Certified for Sport program verifies that the contents match the label, that there are no unsafe levels of contaminants, and that products contain none of 290 substances banned by major athletic organizations.

Go to NSF's certified dietary supplements search at info.nsf.org/Certified/Dietary/. Type at least three letters of the product name, or the company name, and search. Each result shows the company, the manufacturing facility, and a row per product with its trade name, form (powder, tablet, softgel) and the maker's recommended daily serving. The page states the date and time the listing is current as of; on our check it read Tuesday, November 3, 2026.

Three things to compare against your bottle:

• The exact product name and form. A brand being listed does not mean every product it sells is. The listing is product by product.
• The serving size. NSF lists the maker's recommended daily serving. If it differs from your label, read both. In our vitamin D guide, one liquid's NSF row says 6 drops while its label says 2 drops, one to three times a day.
• The company. The listing names the company that holds the certification, which may be a retailer: up&up products appear under Target Corporation.

For athletes who are drug tested, NSF's separate Certified for Sport directory at nsfsport.com can be searched by product, company or lot number.

The NIH Office of Dietary Supplements runs the Dietary Supplement Label Database (DSLD) at dsld.od.nih.gov. Search the product name. Each record is one version of a label: every ingredient with its amount per serving, the other ingredients, the serving size, the date the label was entered, and a flag when the product is marked off the market.

What to look for:

• The entry date. Formulas change. A record entered in 2013 may not match today's bottle. In our magnesium guide, one record dates from March 2013.
• The off-market flag. We do not rank a product whose only label records are marked off the market, even when it is certified, because we cannot verify its current formula.
• The real dose. For minerals, the Supplement Facts amount is the element, not the compound. A product sold as "Magnesium Glycinate 400 mg" declares 60 mg of magnesium per capsule. For fish oil, read EPA plus DHA, not total oil.
• Obvious entry errors. Records are entered by people. We found one giving vitamin D in milligrams instead of micrograms, and one giving omega-3s in grams instead of milligrams. When a record and the product name disagree, trust neither until you read the bottle.

USP Verified. The US Pharmacopeia runs a separate verification program. Its public lookup refused our automated requests on November 3, 2026, so every table on this site marks USP status "not checked". If you see a USP mark on a bottle, check it on USP's own site in your browser.

What certification does not tell you. It says the product matches its label and meets the standard. It does not say the supplement works, that the dose is right for you, or that it is safe with your medicines. Those questions need the evidence and, often, your pharmacist.

Listings change. NSF's listing page warns that it is concerned about fraudulent downloading and manipulation of its text, and asks readers to confirm status on the live listing. A screenshot or a seal from last year is not today's status.

Every product table in our supplement buyer's guides follows one rule: we rank by third-party testing, then form, then dose. A product earns a row only if it is on NSF's listing on the day we check and has a current NIH label record we can match to the same NSF row. Each row links to both records and carries the date we read them. Form and dose are judged against the NIH Office of Dietary Supplements' fact sheets. No product pays to be included, and partner status is never a ranking input.

The scale is large. On November 3, 2026, NSF's listing held 386 rows with "creatine" in the product name alone. Our tables are shortlists of widely sold brands that pass, not the full list; leaving a product off is not a judgment against it.

The guides built this way: creatine, vitamin D, magnesium, fish oil, and multivitamins for women over 50 and men over 50.