The supplement aisle is overwhelming. Some products are excellent; others are expensive placebos. Here's how to tell the difference.
The #1 Sign of Quality: Third-Party Testing
Third-party testing means an independent lab verified the product contains what the label claims and isn't contaminated.
Look for these certifications:
NSF International - Tests for contaminants and label accuracy. NSF Certified for Sport also screens for banned substances.
USP Verified - Similar to NSF. Common on vitamins.
ConsumerLab - Tests and publishes results publicly. Not a certification, but products that pass are reliable.
Informed Sport - Important for athletes. Tests for substances banned in competition.
IFOS - Specifically for fish oils. Tests purity, potency, and freshness.
No certification doesn't mean bad quality, but certification removes guesswork.
Check the Dose (Is It Therapeutic?)
Many supplements are underdosed. Compare the label to clinical trial doses.
Examples of common underdosing:
- Ashwagandha: Clinical dose is 300-600mg. Some products have 100mg. - Omega-3: Therapeutic dose is 1-3g EPA/DHA. Some products have 300mg. - Magnesium: Effective dose is 200-400mg. Some have 50mg (with "400mg magnesium oxide" which has 4% absorption).
How to check: Search "[ingredient name] clinical dose" or look up studies. We provide clinical dose ranges for every ingredient on this site.
Avoid Proprietary Blends
A "proprietary blend" lists ingredients but not individual amounts. They're hiding something.
Example label: "Proprietary Energy Blend 500mg: Caffeine, Green Tea Extract, Guarana, Taurine"
You have no idea how much caffeine is in there. Could be 50mg or 300mg.
Why companies use them: - Hide underdosing (cheap ingredients front-loaded, expensive ones trace amounts) - Protect "formulas" (rarely legitimate) - Create complexity that sounds impressive
Rule: If they won't tell you how much, they're probably not giving you enough.
Check the Form
Not all forms of a nutrient are equal.
Better forms: - Vitamin D3 > D2 - Methylfolate > Folic acid (for ~40% with MTHFR variants) - Magnesium glycinate or citrate > oxide - Methylcobalamin > cyanocobalamin (B12) - CoQ10 ubiquinol > ubiquinone (for those 40+) - Zinc picolinate or glycinate > oxide
Why it matters: Better forms are better absorbed or more bioavailable. The cheap form might be technically present but barely used by your body.
Other Quality Indicators
Manufacturing standards: Look for "GMP certified" (Good Manufacturing Practices).
Minimal fillers: Some fillers are necessary (flow agents, capsule materials). But long lists of artificial colors, flavors, or questionable additives are red flags.
Clear expiration dates: Potency degrades over time. Avoid products without dates or with dates that have passed.
Brand reputation: Established brands (NOW, Thorne, Pure Encapsulations, Jarrow, Nordic Naturals) have more to lose from quality problems.
Transparent sourcing: Where did the fish oil come from? Is the ashwagandha KSM-66 or generic? Details matter.
The Bottom Line
Quality supplements exist, but you have to look. Third-party testing is the strongest signal. After that, check doses, forms, and avoid proprietary blends.