01/25/2026
When people ask me what specific supplements I recommend, the FIRST thing I do is explain 3rd Party Testing. There is NO point in purchasing a product if you are not even sure if it contains what the label says it contains.
If you take vitamins, supplements, use protein powders, pre-workout or any type of similar product, read this! Make sure you're not wasting money and risking your health.
The supplement industry is highly unregulated.
Most supplement labels bundle three very different questions into one reassuring-looking seal.
1) Was it made carefully?
2) Does the bottle actually contain what it claims?
3) And does taking it improve your health in any meaningful way?
Those questions feel closely related, but they have very different answers.
That blur is doing a lot of work in the supplement aisle, and it’s why terms like “GMP,” “USP,” and “NSF” end up carrying far more weight than they deserve.
I wrote this piece to separate those questions cleanly and show what these labels can tell you, and where their usefulness ends.
If you want to read labels with clearer eyes and fewer assumptions, this one will be worth your time.
Read my thoughts here ⬇️
𝐁𝐨𝐭𝐭𝐨𝐦 𝐥𝐢𝐧𝐞 𝐮𝐩 𝐟𝐫𝐨𝐧𝐭:
These acronyms (GMP, USP, NSF) are useful quality tools. However, they can not provide proof that a supplement works. They help answer different narrow questions about manufacturing and verification like “Was this made properly?” and “Does the dose match the label?”
Here’s where this matters in the real world: when CVS decided to require third-party testing for every supplement it sells, they found that about 7% of products failed and had to be reformulated or removed from the shelves.
When studies check the quality of dietary supplements, there can be huge differences across products, and some don’t meet even the most basic quality and labeling expectations.
That’s the gap these labels like “USP” and “NSF” are trying to fill.
𝐓𝐡𝐞 𝐭𝐡𝐫𝐞𝐞 𝐪𝐮𝐞𝐬𝐭𝐢𝐨𝐧𝐬 𝐭𝐡𝐚𝐭 𝐠𝐞𝐭 𝐛𝐥𝐮𝐫𝐫𝐞𝐝 𝐭𝐨𝐠𝐞𝐭𝐡𝐞𝐫
Most people implicitly roll several very different questions into one:
1) Was this specific product made in a controlled, documented way?
2) Does each dose contain what the label says it contains, without specific contaminants?
3) Does this product actually improve health outcomes? Do its benefits outweigh its risks?
Different labels answer different parts of that list.
GMP mostly addresses question #1
USP and NSF mostly address question #2
None of them address question #3
Keeping those questions separate clears up most of the confusion.
𝐆𝐌𝐏: 𝐡𝐨𝐰 𝐢𝐭 𝐰𝐚𝐬 𝐦𝐚𝐝𝐞
GMP stands for Good Manufacturing Practices. In the U.S., GMP compliance for dietary supplements is legally required. That means that saying “GMP” on a label usually tells you very little about how well that requirement is actually being met.
GMP means the manufacturer follows FDA rules that govern things like sanitation, documentation, ingredient handling, and quality control systems. It reduces the chance of sloppy mistakes, mix-ups, or contamination.
What GMP does not do is certify that:
- the finished product matches the label
- the dose is biologically or clinically meaningful
- the supplement is safe to consume
At its core, GMP tells you about the factory’s habits.
𝐈𝐧𝐝𝐞𝐩𝐞𝐧𝐝𝐞𝐧𝐭 𝐪𝐮𝐚𝐥𝐢𝐭𝐲 𝐯𝐞𝐫𝐢𝐟𝐢𝐜𝐚𝐭𝐢𝐨𝐧 (𝐔𝐒𝐏, 𝐍𝐒𝐅, 𝐚𝐧𝐝 𝐨𝐭𝐡𝐞𝐫𝐬)
Once GMP is assumed (due to the legal requirement), the real question becomes:
What extra reassurance do I want beyond basic manufacturing rules?
This is where USP and NSF come in.
For most people, it’s more helpful to think of USP and NSF together rather than as competing systems. Both are attempts to independently check whether a product matches its label and meets defined quality criteria.
At a high level, they aim to reduce uncertainty about:
- whether the ingredient is actually present at the stated amount
- whether certain known contaminants are below defined limits
That’s meaningful information, especially in a market where many products are never independently verified at all.
𝐖𝐡𝐞𝐫𝐞 𝐭𝐡𝐞𝐲 𝐝𝐢𝐟𝐟𝐞𝐫…
You don’t really need to memorize this, but it may help to know the emphasis of USP vs. NSF:
- USP focuses on whether a product meets predefined standards for identity, purity, strength, and performance
- NSF focuses on independent testing against program-specific criteria, often with stronger emphasis on contamination screening.
In practice:
- USP is often most informative for simple, single-ingredient supplements (like vitamins and minerals)
- NSF is often most informative for complex products (like protein powders or multi-ingredient blends)
For most everyday use, either mark generally serves the same practical purpose: confirming that someone outside the manufacturer checked the product in some way.
If someone chooses to buy a supplement, third-party verification is one of the few signals that actually reduces uncertainty around the quality of a product.
𝐖𝐡𝐚𝐭 𝐢𝐧𝐝𝐞𝐩𝐞𝐧𝐝𝐞𝐧𝐭 𝐯𝐞𝐫𝐢𝐟𝐢𝐜𝐚𝐭𝐢𝐨𝐧 𝐬𝐭𝐢𝐥𝐥 𝐝𝐨𝐞𝐬 NOT 𝐝𝐨
Even when a supplement carries a USP or NSF mark, that verification does not:
- assess clinical benefit or risk
- determine whether the supplement is worth taking for you (or anyone)
- tell you whether the dose meaningfully improves health outcomes
Quality verification narrows uncertainty about what’s in that specific bottle.
𝐓𝐡𝐞 𝐭𝐚𝐤𝐞𝐚𝐰𝐚𝐲
If you remember nothing else, remember this:
GMP is legally required and describes how a supplement was made
USP / NSF indicate third-party checks that the label is likely honest and certain quality standards were met
None of these labels tell you whether a specific supplement is a good idea for your health.
-Morgan McSweeney, PhD (.noc)
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