How to Read a Supplement Label (and Spot Red Flags)

Supplement labels are designed to look impressive. Here's how to see through the marketing and evaluate what you're actually getting.

The Supplement Facts Panel

Every supplement is required to have a "Supplement Facts" panel (similar to "Nutrition Facts" on food). Here's what to look at:

Serving Size

Always check this first. Some brands list impressive ingredient amounts per "serving" — but a serving might be 4 capsules. If the bottle has 60 capsules, that's only a 15-day supply, not 60 days. Compare per-serving cost, not per-bottle cost.

Amount Per Serving

This tells you how much of each ingredient you're getting. Compare against evidence-based dosages:

• Vitamin D — most studies use 1,000-5,000 IU. If a product has 400 IU, it may be underdosed.
• Magnesium — effective doses are typically 200-400mg of elemental magnesium.
• Omega-3 — look for 500-1000mg of combined EPA+DHA, not just "fish oil."
• Probiotics — measured in CFUs (Colony Forming Units). Look for billions, not millions.

% Daily Value (%DV)

Based on FDA reference amounts. 100% DV means you're getting the full recommended daily amount. Some vitamins are fine above 100% (water-soluble vitamins like B and C), while others can be problematic in excess (fat-soluble vitamins A, D, E, K).

Red Flag #1: Proprietary Blends

This is the biggest red flag in the supplement industry. A "proprietary blend" lists ingredients but not individual amounts. You'll see something like:

You know the total blend is 500mg, but you have no idea how much of each ingredient is in it. The blend could be 490mg caffeine and 2.5mg of everything else. Companies use proprietary blends to hide underdosing of expensive ingredients.

Our stance: Brands that use proprietary blends receive a -10 point penalty in our trust score algorithm.

Red Flag #2: "Other Ingredients"

Below the Supplement Facts panel is the "Other Ingredients" section. This lists fillers, binders, coatings, and additives. Common ones include:

• Magnesium stearate — a flow agent. Generally safe but overused.
• Silicon dioxide — prevents caking. Generally safe.
• Titanium dioxide — a coloring agent. Banned in the EU for food use since 2022.
• Artificial colors (Red 40, Yellow 6, Blue 1) — unnecessary in supplements.
• Maltodextrin, sugar, corn syrup — often in gummies and flavored products.

Fewer "other ingredients" generally means a cleaner product. Some premium brands use only the capsule shell and the active ingredient.

Red Flag #3: Form Matters

The form of an ingredient dramatically affects absorption:

• Magnesium oxide — cheapest, worst absorbed (~4% bioavailability)
• Magnesium glycinate — well-absorbed, gentle on stomach
• Magnesium citrate — well-absorbed, may have laxative effect

Similarly for B12: cyanocobalamin is cheap and synthetic. Methylcobalamin is the active form your body actually uses. For folate: folic acid is synthetic. Methylfolate (5-MTHF) is the bioactive form.

Budget brands typically use the cheapest forms. Premium brands use bioavailable forms and list them specifically.

Red Flag #4: Unrealistic Claims

By law, supplements cannot claim to treat, cure, or prevent disease. Watch out for:

• "Clinically proven" without citing specific studies
• "Doctor recommended" without naming the doctor or the recommendation context
• Before/after photos (illegal for supplements)
• Any disease claims ("fights cancer," "prevents Alzheimer's")

What Good Labels Look Like

Trustworthy supplement labels typically have:

• Individual ingredient amounts (no proprietary blends)
• Specific ingredient forms listed (e.g., "Magnesium (as Magnesium Glycinate)")
• Third-party certification logos (NSF, USP, Informed Sport)
• Minimal "other ingredients"
• Lot number and expiration date
• Manufacturer contact information