Supplements are everywhere. They’re promoted by your favorite podcaster. They line the shelves of health food stores and big-box retailers. You can even grab them at a gas station on a road trip.
That abundance raises a fair question: How do you know if a supplement is high-quality?
Here’s some real talk: The supplement industry isn’t regulated the same way pharmaceuticals are. That doesn’t mean all supplements are unreliable, but it does mean quality can be all over the map. The good news is that there are clear ways to identify high-quality supplements once you know what to look for.
High-quality supplements should be thoroughly tested for contaminants.** That includes heavy metals like arsenic and lead, along with harmful microbes such as salmonella and E. coli. But from the outside, how can you tell what’s actually been tested? How do you know the dosage and ingredient amounts listed on the bottle reflect what you’re really taking?
The answer isn’t found in flashy packaging or over-the-top claims. It lives in rigorous testing practices, responsible manufacturing standards, and credible third-party certifications. Once you understand these markers, you’ll be more educated about supplements and be ready to take better ownership of your wellness.
We know what you’re thinking: Every supplement brand claims to be premium. At Nature’s Life, we won’t pretend we’re above that conversation. But since 1975, our goal isn’t to sell you hype. It’s to give you the information you need to make empowered choices. No matter where you buy your supplements, they should be made with care, transparency, and respect for your health.
Certifications
While supplements are regulated by the Food and Drug Administration, they don’t need FDA approval to hit shelves. That’s why third-party certifications play such an important role. These independent organizations provide oversight where regulation stops, helping hold brands accountable for what happens behind the scenes.
When certifications are earned and actively maintained, brands can display official seals on their packaging. Those seals aren’t decoration. They signal that specific manufacturing or testing standards have been met—not just promised.
Examples of certifications include:
- ISO (International Organization for Standardization)
- cGMP (Current Good Manufacturing Practices)
Other certs include the dietary kind. Each of these is important and can’t legally be stamped on a bottle unless certain standards are met and regularly recertified. Let’s break down what they all mean.
ISO
ISO is a globally recognized accreditation focused on laboratory and testing practices. It’s difficult to earn and just as demanding to maintain.
ISO certification means lab processes are carefully monitored, documented, and reviewed on an ongoing basis. Companies must recertify annually through detailed evaluations, making it a strong indicator of consistent and controlled testing practices.
cGMP
cGMP, overseen by organizations like the FDA and NSF (National Sanitation Foundation), is one of the most respected manufacturing standards in the supplement world. It ensures supplements are produced safely, consistently, and according to strict quality requirements.
In practical terms, cGMP is a rigorous standard for manufacturing that ensures you’re getting exactly what the bottle says you are.
Dietary certifications
Some brands pursue additional certifications to meet specific dietary needs or preferences. These may include:
- Kosher
- Vegan
- Made Without Soy
Each certification has its own governing body, and brands must meet ongoing requirements to keep the seal. When you see one of these certifications, it means standards have been verified, not self-declared.
Sourcing
Supplement ingredients come from all over the world. That makes sourcing a pretty complex endeavor, and incredibly critical. With hundreds of potential suppliers and huge variation in quality, sourcing is where shortcuts can happen.
Responsible brands vet suppliers carefully and test raw materials before production. And when they get their material, they test every lot to make sure it meets high standards for purity and potency.
At Nature’s Life, sourcing isn’t an afterthought. Ingredients are selected intentionally and tested to confirm identity and integrity before they ever reach the production line.
Testing
Most supplement manufacturers test their products. But not all testing is equal.
ISO focuses on lab oversight. GMP ensures testing throughout manufacturing. Together, they help support consistency and reliability.
Some companies rely on skip-lot testing, where only a small portion of a batch is tested and the rest is cleared. That approach saves time, but it increases risk. We believe quality is worth checking, every time, and we never do skip-lot testing at intake.
Formulation & Bioavailability
So, now your supplements are being made with carefully sourced ingredients and rigorously tested for purity, potency, and identity. How do we know if they’ll actually work to support your health?
Using science-backed ingredients is only half the equation. Those ingredients need to be absorbed by your body to use them. That’s where bioavailability comes in.
Once ingested, supplements are broken down in the stomach, absorbed in the gut, processed by the liver, and delivered through the bloodstream. If nutrients don’t survive that journey, they can’t support your body the way they’re intended to.¹
Before you start taking a supplement, do some quick research for the best ways to take it. For instance, did you know that it’s best to take zinc and copper together because they both compete for absorption, so taking one without the other can lead to imbalance in the body? Looking at peer-reviewed sources, as well as consulting your primary care physician, will help you choose supplements that work for your body.
Learn more about how to read supplement labels here →
New vs. Established Brands
Because supplements don’t require FDA approval before launch, new brands can appear overnight. Some are thoughtful and responsible. Others rely on aggressive marketing before quality systems are fully in place. They’ve even been known to change their name in order to stay ahead of accountability.
Buying supplements online can be perfectly safe, but transparency matters. Look for brands with accessible labels, clear sourcing information, and a visible track record. Established brands tend to have systems that support consistency over time.²
Scientific Backing
Quality supplements don’t hide their details. Ingredient lists and supplement facts should be easy to find and easy to understand.
Brands that make this information difficult to access may be cutting corners. Trustworthy supplements don’t rely on mystery to appeal to their customers.
Too Good to Be True
Be cautious of supplements that promise dramatic or instant results, especially when it comes to weight loss, muscle gain, or sexual performance.¹
Supplements are designed to support your body, not override biology. Favor nutrients that have been well-studied, like magnesium, zinc, and vitamin B12. Reliable research sources like the National Institutes of Health database can help you verify claims.
The Role of Supplements
The word supplement means something that adds to something else. In nutrition, that foundation is food.
At Nature’s Life, we believe in working hand-in-hand with Mother Nature. Whole foods are important, but modern farming, soil nutrient depletion, and food processing can make it harder to get the nutrients your body depends on from diet alone.
That’s where supplements come in. They offer the power of nature's most essential minerals to help fill in the gaps.*
Our Promise
At Nature’s Life, we believe wellness should never feel confusing or opaque. Transparency, thoughtful formulation, and clear labeling mean everything to us. It’s how we walk the walk.
Wherever you buy your supplements, we hope this guide helps you ask better questions, read labels more critically, and expect more from the brands you buy from.
Follow @natureslifevitamins on Instagram for more radical wellness tips.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
**Tested up to 10 parts per billion.
Resources
- Shetty, M. Considerations When Choosing Supplements. Stanford Lifestyle Medicine, 2024. https://longevity.stanford.edu/lifestyle/2024/03/11/considerations-when-choosing-supplements/
- Tips for Consumers Selecting Supplements. The Council for Responsible Nutrition, https://www.crnusa.org/resources/tips-consumers-selecting-supplements.