USP and GMP: Your Guide to Supplement Quality Standards

Ever notice how the supplement aisle can seem a bit overwhelming? How can you know that the one you select is the best quality and delivers the truest label claims? The answer lies in transparent practices and quality control—not by the manufacturer, but by a trusted third party. That’s where certification and verification come in.

The two most common or prominent notations or claims you will see are USP and GMP. Keep reading to learn all about them.

What Are USP and GMP for Supplements?

USP and GMP verifications exist for a very important reason: your safety! When you choose to take a health supplement, you’re placing your trust in its manufacturer to provide pure, potent ingredients that match the bottle label exactly. USP and GMP verifications exist to ensure this and prevent issues like labeling errors, mix-ups or contamination of product.

These concerns are well-grounded, as dietary supplements aren’t regulated in the same manner as prescription drugs, and so manufacturers who don’t participate in third-party programs may provide product that isn’t held to quality standards most of us take for granted.

USP Verification and What it Means

USP (U.S. Pharmacopeia) is a voluntary testing and auditing program that helps dietary supplement manufactures ensure a high quality of products for consumers.

How Does USP Verification Work?

When a product is USP Verified, it means that the purity, potency and quality of the product has been examined and guaranteed. When you see the USP Verified mark on a supplement bottle, it means that the product formulation has been tested, and the manufacturing facility audited by USP through its voluntary verification program. This mark indicates that the product:

• Contains the ingredients listed on the label, in the declared strengths
• Meets USP standards for purity and limits on contaminants like heavy metals and harmful microbes or other adulterating ingredients.¹
• Breaks down properly in the body, as confirmed by disintegration testing.
• Was manufactured in a facility that complies with USP’s interpretation of the FDA’s Good Manufacturing Practices (GMPs).¹

The verification process includes an audit of the manufacturer’s facility to ensure compliance with the FDA’s GMP guidelines and USP dietary supplement guidelines on sanitation and safety. It also requires the review of quality control and manufacturing documents at the facility. Finally, the process requires both laboratory and “off-the-shelf” testing of product samples to confirm ingredient purity and potency—during and after manufacture and distribution.¹

Is USP Verification Worth It? (Here's Why it Matters)

The benefits of USP verification are real and plentiful, including promoting consumer confidence, ensuring public safety and supporting efforts to enhance quality standards in the dietary supplement industry.

USP verification works to prevent the contamination of products with unsafe or incorrect ingredients. It also identifies unsafe or unsanitary conditions in facilities so that these can be corrected. Think of it like the anti-virus software that scans your emails before you open them. When you see that USP verification mark on the bottle, you know its contents and the manufacturer have been “scanned” for best practices.

What USP Does Not Cover

A common misconception is that USP verification means that the product is guaranteed to deliver the health benefits it may claim to, or that the FDA has reviewed more than just the structure function claims or has approved of the product as a whole. This is not the case. Dietary supplements are regulated like food items and not like medicines. So, while USP verification of medicines is required by law, the standards being certified are different than those for supplements.² USP doesn’t certify—they verify. They also don’t verify efficacy of dietary supplements.

GMP: The Behind-The-Scenes Quality Control

When it comes to supplement quality, USP and GMP aren’t competing standards—they work together, and at times overlap. While USP focuses on the testing of ingredients and finished products, GMP is all about how these products are made, tested and controlled from start to finish.

Required by the FDA under 21 CFR Part 111, GMPs are the legal foundation for supplement manufacturing. They cover every part of the process, from sourcing raw materials and sanitizing equipment, to training personnel, to documenting procedures and ensuring proper storage, packaging and distribution. They also require manufacturers to have laboratory controls in place—to test ingredients and finished products using scientifically valid methods and to investigate any out-of-specification results before product release.

GMPs even extend to how manufacturers investigate product complaints and returned items, ensuring that any potential safety or quality concerns are identified, documented and addressed before they become widespread problems.

Unlike individual product testing, GMPs are designed to build quality into the process from the very beginning so that every bottle you open meets the same high standard, every time.

What GMP Actually Does (It's More Than You Think)

GMPs aren’t just about cleanliness or passing an audit. It’s a legally required system that governs how supplements are made, tested, handled and documented from start to finish.

To verify GMP compliance, companies routinely undergo GMP audits by the FDA, third-party organizations and internal quality teams. A GMP audit examines how well a manufacturing operation meets regulatory expectations across:

1. Personnel training and hygiene
2. Facility and equipment sanitation and maintenance
3. Manufacturing and packaging procedures
4. Laboratory controls and test methods
5. Recordkeeping and traceability
6. Handling of product complaints and returns

A GMP audit is like a quality system stress test. It verifies that every ingredient, process and product meets strict standards, and that there’s documentation to back it up. When it comes to supplements, quality isn’t something you test in the end—it’s something you build from the start.

GMP vs. Food Safety: Why Supplements Need Higher Standards

Dietary supplements are regulated as a category of food, but they don’t follow the same manufacturing rulebook. While food companies follow GMPs under 21 CFR 117, supplements are governed by a separate and stricter standard: 21 CFR Part 111.

Why the difference? Because supplements aren’t just about flavor and calories—they’re formulated to deliver specific ingredients at precise levels, and that requires more control.

How Supplement GMPs Go Further

1. Ingredient Identity Testing: Every dietary ingredient must be tested for identity before use.
2. Finished Product Specifications: Supplements must meet defined specs for strength, purity and composition.
3. Written Batch Records: Every formula and manufacturing step must be documented and followed precisely.
4. Label Reconciliation: Label use must be tracked to prevent mix-ups and ensure traceability.
5. Complaint & Return Investigation: Every issue must be logged, investigated and resolved.

These rules are more than best practice—they’re federally mandated safeguards to protect product integrity from start to finish.

Swanson's Compliance Commitment

At Swanson, we go beyond the basics. Our facility complies with:

• 21 CFR Part 111 (GMPs for Dietary Supplements
• 21 CFR Part 117 (GMPs and Preventive Controls for Food)
• 21 CFR Part 121 (Intentional Adulteration/Food Defense)

That means we’re not just following the rules for supplements—we’re also meeting federal expectations for food safety and food defense.

Supplement GMPs are designed to ensure the identity and purity of raw materials, the consistency of manufacturing processes and the quality and potency of the final product.³

NSF-GMP: When GMP Gets Even Better

GMP isn’t optional. But when you see NSF/ANSI 455-2 GMP certification, you know a company isn’t just meeting the minimum; they’re proving it, through comprehensive third-party audits that go far beyond the basics.

Swanson is certified to NSF/ANSI 455-2, a consensus built specifically for the dietary supplement industry. This certification includes all the FDA-required GMPs under 21 CFR Part 111, but it doesn’t stop there. The scope also covers:

• 21 CFR Part 117
• 21 CFR Part 11
• 21 CFR Part 1.5 Subpart L
• 21 CFR Part 1.9 Subpart O

Every year, NSF auditors assess our entire quality system: from raw material control and supplier oversight, to in-house testing, complaint handling, sanitation, documentation and everything in between.

This isn’t a one-and-done certification. It’s a routine deep-dive into how we operate, ensuring that our products aren’t just safe and compliant, but manufactured under tight controls, traceable systems and with documented proof at every step. Swanson doesn’t just say we’re compliant. We prove it.

NSF has been providing certification for more than 80 years and is recognized as one of the premier independent organizations operating globally for this purpose. NSF-GMP certification is available for dietary supplements, over-the-counter drugs and even cosmetics. The certification provides even higher requirements for purity and safety across the entire supply chain, from the manufacture of the supplement all the way through to the consumer.³ Companies volunteer for an NSF-GMP certification audit of their facilities and procedures as a way of communicating to their customers that they place the highest value on quality and safety in all their operations.

USP Verification & GMP Certification: What's the Difference?

USP and GMP are both crucial to supplement quality, but they aren’t the same thing. And despite what you might see online, neither replaces the other. Here’s how they actually work together.

One (GMP) controls the system. The other (USP) confirms the result. Both matter. But only GMP compliance is mandated by law. GMP certification is voluntary (as is USP Verification).

The GMP mark won’t be on products, but USP Verified can be.

USP & GMP: The Key Differences That Matter to You

Remember that USP verification focusses on standards for products—their ingredient purity and potency. GMP is angled more toward the process of crafting those products. You may see one or both indicated by a manufacturer, indicating the company’s choice in voluntary submission to audits. Either way, it isn’t a simple thing to call one or the other “better” as they both focus on separate, yet closely-knit aspects of the preparation of your supplements.

The FDA Connection: What They Actually Do (And Don't Do)

The truth about FDA regulation of dietary supplements is that the agency is not required under the law to approve supplements for effectiveness or safety, nor to approve their bottle labels before they’re marketed to the public.⁴ This doesn’t mean that the FDA isn’t involved, however. Its authority is post-market: recall requests, warning letters, seizure and injunction—but only when a product is patented unsafe, adulterated or makes claims implying disease treatment.

In addition to enforcing these regulations, the FDA also requires dietary supplement manufacturers to register their facilities. This registration required under the Bioterrorism Act and the Food Safety Modernization Act (FSMA), must be renewed every two years and allows the FDA to know where the supplements are made and hold manufacturers accountable.

The law lays out different FDA regulations and responsibilities for manufacturers of food (which includes supplements) and medicinal drugs, which is why identifying those companies which have FDA registered facilities and which voluntarily submit to third-party programs is so important. If you find a supplement company which offers “FDA approved” supplements or claims, steer clear—these are false marketing tactics and should be considered a red flag. Instead, look for the safeguards described above when considering your supplement source.

Real Talk: What This Means for Your Medicine Cabinet

Should You Throw Out Your Non-Certified Supplements?

If you’ve got bottles in your cabinet that don’t meet these standards, don’t panic—it doesn’t automatically mean they’re unsafe or low quality. But it does mean you might want to take a closer look.

Visit the brand’s website. Do they talk about how their products are tested? Do they disclose whether they follow GMPs and whether their facilities are independently audited? Are they transparent about ingredient sourcing and quality standards?

How Can You Tell if a Supplement Brand is Trustworthy?

Before buying a supplement, ask yourself:

• Is this company GMP-certified by an accredited third-party organization?
• Is the facility registered with the FDA and compliant with inspection requirements?
• Are their claims realistic, or do they sound too good to be true?
• Does the company have a proven track record of quality and accuracy?

The answers to these questions can go a long way to helping you make the best choice.

The Swanson Approach: Walking the Walk

While GMPs are legally required, Swanson takes it further by voluntarily participating in third-party GMP certification. For us, quality isn’t a checkbox—it’s a mindset built into everything we do. From our sourcing standards to how we test and label each product, we operate with full transparency because your health deserves nothing better.

We’ve followed Current Good Manufacturing Practices (cGMPs) since 2001—well before enforcement of 21 CFR Part 111 took effect, and our Fargo, ND facility is GMP Certified by both NSF and UL—two independent, internationally recognized organizations that aim to promote consumer and product safety. That means we’re routinely audited against FDA regulations and industry best practices, not because we have to, but because we believe in it. This commitment isn’t new—our adherence to the highest standards predates even some FDA regulations!

For example, our ingredients require clear documentation from suppliers, including raw material specification and a Certificate of Analysis—and even then, we only work with suppliers we trust. Ingredients are tested at various stages throughout the production process to verify purity and potency. Finished products are tested by independent third-party laboratories—this way you know for certain that the product only contains ingredients listed on the label.

We’ve been operating in compliance with Current Good Manufacturing Practices (cGMPs) since 2001—almost a decade earlier than industry enforcement by the FDA. These practices represent the most recent, and more rigorous, quality standards regulated by the FDA.⁵ Our facility in Fargo, ND is recognized as a Certified GMP Facility by NSF, meaning our headquarters is routinely audited against accredited standards to ensure total compliance with federal regulations and industry best practices. All of this serves as an expression of our unwavering support for the very best in purity, potency and quality for our customers.

If you want to know more about a company and their quality control, look for information on their website or packaging.

Your Next Steps: Making Quality Count

We’ve explored how third-party verification and GMP certification help ensure that dietary supplements meet the highest standards, and we’ve also looked at how the FDA handles dietary supplements and their facilities. With this information in hand, it’s time to make a game plan for your health regimen. Don’t forget the age-old Pareto Principle: 80% of your results come from 20% of your actions! This means applying even a small amount of effort in researching the companies you buy from can make a big difference.

The best plan is to begin right where you are and then to start implementing what you’ve learned. This may mean changing which supplements you take or which companies you buy them from. Equipped with the right knowledge, you’re sure to succeed—and we’ll be here with you every step of the way.

You be well, now.
Swanson

*These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease.

Sources

1. USP Verification Mark. Accessed July 2025. Read source

2. USP and Dietary Supplements. Accessed July 2025. Read source

3. Food and Dietary Supplement Regulations Compared. Accessed July 2025. Read source

4. FDA 101: Dietary Supplements. FDA. Accessed July 2025. Read source

5. Facts About the Current Good Manufacturing Practice. USFDA. Read source