The Regulatory Gap
Before we discuss testing programs, it's important to understand why third-party testing exists. The Dietary Supplement Health and Education Act (DSHEA) of 1994 established the current regulatory framework for supplements in the United States. Under DSHEA, supplements are regulated as food, not drugs. This means:
- No pre-market approval: Unlike prescription drugs, supplements do not need FDA approval before being sold. The burden is on the FDA to prove a supplement is unsafe after it reaches the market
- Manufacturer responsibility: Companies are required to ensure their products are safe, properly labeled, and manufactured according to Good Manufacturing Practices (GMP). But enforcement is largely reactive
- Limited inspection resources: The FDA estimates there are over 80,000 dietary supplement products on the market from roughly 5,800 manufacturers. The agency inspects a small fraction each year
This does not mean supplements are unregulated. Companies can be held liable for adulteration, mislabeling, and making drug claims. But there is no gatekeeper ensuring quality before products reach shelves. Third-party testing fills this gap voluntarily.
The Evidence for Quality Concerns
Is the concern about supplement quality justified? The data says yes:
- A 2013 study published in BMC Medicine tested 44 herbal supplements from 12 companies and found that 59% contained plant species not listed on the label. One-third contained fillers and contaminants not disclosed on the label
- A 2017 study in the Journal of Clinical Sleep Medicine tested 31 melatonin supplements and found that actual melatonin content ranged from -83% to +478% compared to label claims. 26% of the products also contained serotonin
- The New York Attorney General's office tested herbal supplements from four major retailers in 2015 and found that 79% did not contain the labeled herbs. DNA barcoding revealed many contained fillers like rice powder and houseplants instead of the labeled herbs
- ConsumerLab.com has tested thousands of supplements over two decades and consistently finds that 20-30% of products have issues including incorrect potency, contamination, or labeling problems
- The FDA has issued hundreds of warning letters for supplements found to contain undeclared drug ingredients, particularly in weight loss, sexual enhancement, and bodybuilding supplements
These are not fringe cases. They represent systemic quality control issues in an industry with limited regulatory oversight. Third-party testing is the most practical way for consumers to reduce this risk.
The Major Testing Programs
USP Verified
What it is: The United States Pharmacopeia (USP) is an independent, nonprofit organization that has set quality standards for medicines since 1820. Their Dietary Supplement Verification Program tests products for identity, strength, purity, and performance (dissolution/disintegration).
What they test for:
- Does the product contain the ingredients listed on the label?
- Does it contain the declared amounts of those ingredients?
- Is it free from harmful levels of contaminants (heavy metals, microbes, pesticides)?
- Will it properly dissolve/disintegrate in the body so the ingredients can be absorbed?
- Was it manufactured according to GMP standards? (includes facility audits)
Rigor level: Very high. USP verification is widely considered the gold standard for supplement quality verification. It includes both product testing and manufacturing facility audits.
Who uses it: Nature Made is the largest USP Verified brand. Kirkland Signature (Costco's house brand) also carries USP verification on many products. It is less common among premium/specialty brands because the certification process is expensive and time-consuming.
How to check: Look for the USP Verified Mark on the product label, or search the USP Verified product database at quality-supplements.org.
NSF International
What it is: NSF International is an independent testing and certification organization. They offer two relevant supplement certifications:
NSF Certified for Sport: The most rigorous certification for athletes. In addition to standard identity, potency, and contaminant testing, NSF Certified for Sport tests every lot of a product for over 270 substances banned by major athletic organizations (WADA, NFL, MLB, NBA, NCAA, etc.).
NSF GMP Registration: Verifies that a manufacturing facility follows Good Manufacturing Practices, but does not test individual products.
What Certified for Sport tests for:
- Everything USP tests (identity, potency, contaminants, dissolution)
- Plus: 270+ banned substances including anabolic steroids, stimulants, beta-2 agonists, masking agents, and narcotics
- Every production lot is tested (not just periodic sampling)
- Annual facility audits
Rigor level: Very high. Particularly important for competitive athletes who face doping tests.
Who uses it: Thorne, Momentous, Klean Athlete, and several other brands targeting athletes. Increasingly adopted by brands that want to demonstrate premium quality even for non-athlete consumers.
How to check: Search nsf.org for Certified for Sport products.
ConsumerLab.com
What it is: ConsumerLab is a private company that independently purchases and tests supplements, then publishes results. Unlike USP and NSF, brands do not apply for ConsumerLab testing. ConsumerLab selects products to test and publishes the results.
What they test for:
- Does the product contain the ingredients in the amounts claimed?
- Is it free from concerning levels of contaminants?
- Does it meet any relevant quality standards?
Rigor level: Moderate to high. ConsumerLab testing is solid but typically less comprehensive than USP or NSF (they don't always test dissolution, for example). The independent purchasing model is a strength, since companies cannot submit specially prepared samples.
Who uses it: Any brand's products can be tested. Brands that pass can license the CL Approved seal. Full reviews are behind a $72/year paywall, but basic pass/fail results are sometimes available publicly.
How to check: consumerlab.com (subscription required for full reports). Some pass/fail information is available through brand marketing materials.
BSCG (Banned Substances Control Group)
What it is: Founded by Dr. Don Catlin (former director of the UCLA Olympic Analytical Laboratory), BSCG is a third-party certification program focused on banned substance testing. Each product lot is tested for over 700 substances on the banned lists of major athletic organizations and governmental regulatory agencies.
What they test for:
- 700+ banned substances (the most comprehensive banned-substance panel available)
- Heavy metals, pesticides, and other contaminants
- Label accuracy for active ingredients
Rigor level: Very high for banned substance testing specifically. The most comprehensive panel of any certification program for detecting banned substances.
Who uses it: Several sport supplement brands, particularly those serving Olympic and professional athletes.
How to check: Search the BSCG certified product database at bscg.org.
Informed Choice / Informed Sport
What it is: Operated by LGC (a UK-based science organization), Informed Choice and Informed Sport test supplement products for banned substances. Informed Sport is the more rigorous program, testing every batch rather than periodic sampling.
What they test for:
- Banned substances (per WADA prohibited list)
- Heavy metals and microbial contamination
- Manufacturing facility audits
Rigor level: High for banned substance testing. Informed Sport (batch testing) is more rigorous than Informed Choice (monthly random testing).
Who uses it: Many mainstream sports nutrition brands.
How to check: Search the database at informed-sport.com or informed-choice.org.
Quick Comparison
| Program | Tests Potency | Tests Contaminants | Tests Banned Substances | Facility Audit | Cost to Brand |
|---|---|---|---|---|---|
| USP Verified | Yes | Yes | No | Yes | High |
| NSF Certified for Sport | Yes | Yes | Yes (270+) | Yes | High |
| ConsumerLab | Yes | Yes | No | No | N/A (independent) |
| BSCG | Yes | Yes | Yes (700+) | No | Moderate |
| Informed Sport | Limited | Yes | Yes | Yes | Moderate |
What "GMP Certified" Means (and Doesn't Mean)
You will see "GMP Certified" on many supplement labels. GMP stands for Good Manufacturing Practices, which are FDA-mandated requirements for supplement manufacturing facilities. All supplement manufacturers are legally required to follow GMP. So "GMP Certified" on a label is like a restaurant advertising "we follow health codes." It is the legal minimum, not a distinction.
That said, some companies go beyond the minimum by getting their GMP compliance independently audited by organizations like NSF or NPA (Natural Products Association). Third-party GMP audits provide more assurance than self-declared GMP compliance.
Does Testing Guarantee a Good Product?
No. Third-party testing verifies that what's on the label is in the bottle. It does not evaluate whether the product is effective. A USP Verified product could contain the exact labeled amount of an ingredient that has no clinical evidence for its claimed benefit. Testing verifies quality and accuracy, not efficacy.
That is why our scoring system at Supplement Scorecard evaluates both quality/testing AND evidence. A product needs to pass on both fronts to receive a high overall score. Read our full scoring methodology for details.
How to Check If Your Supplement Is Tested
- Look at the product label for certification marks (USP, NSF, CL, BSCG, Informed Choice)
- Check the brand's website for quality/testing information
- Search the certification databases directly (linked above for each program)
- If you cannot find any third-party testing evidence, contact the manufacturer and ask. Reputable companies will be happy to share their testing practices
- If a company refuses to share testing information or has no third-party verification, consider switching to a brand that does
Our Recommendation
We strongly recommend choosing products with at least one third-party certification, especially for supplements where contamination risk is higher (herbal extracts, products sourced from countries with less regulatory oversight, and sports nutrition products). The cost premium for tested products is typically $0.02-$0.10 per day. It is worth it for the assurance.
Every product in our database is evaluated on its third-party testing status as part of the Quality & Purity score. Browse our supplement scorecards to see how specific products compare on quality verification.