Supplement Label Claims: What Third-Party Testing Actually Verifies

What is label-claim testing?

Label-claim testing — also called potency verification or active-ingredient verification — is an analytical test that confirms whether a supplement product contains the amount of active ingredient stated on its label.

Under the FDA’s Dietary Supplement Health and Education Act (DSHEA) and Good Manufacturing Practice (GMP) requirements, supplement manufacturers are responsible for ensuring that their products contain the labeled amount of each active ingredient. Label-claim testing provides documented evidence of this.

How far off are supplement labels?

Independent research has consistently found that a significant proportion of dietary supplements do not match their label claims. Some contain less than labeled (under-dosing), some contain more (over-dosing), and some contain entirely different or substitute ingredients.

• Under-dosed — contains less active ingredient than labeled. Most common issue.
• Over-dosed — contains more than labeled. A safety and liability concern, especially for fat-soluble vitamins.
• Wrong ingredient — a substitute or cheaper compound used instead of the labeled ingredient.

What label-claim testing measures

A complete label-claim test panel for a dietary supplement typically includes:

Active-ingredient potency (HPLC)

Quantifies the exact amount of each labeled active ingredient per serving. Expressed as mg / serving or % of label claim — e.g. “102 % of label claim” or “8.7 mg per 10 mg serving (87 % label claim).”

Identity confirmation (MS or FTIR)

Confirms the ingredient is what it claims to be — not a cheaper analog or different compound. For botanicals, this may use DNA barcoding or specific marker-compound testing.

Heavy-metals panel (ICP-MS)

Tests for lead, mercury, arsenic, and cadmium at parts-per-billion levels. Critical for California Prop 65 compliance and premium supplement positioning.

Microbial testing (USP <61>/<62>)

Total aerobic plate count, yeast / mold, E. coli, Salmonella, S. aureus. Required for GMP compliance.

Why your supplement brand needs third-party COAs

There are five business-critical reasons to obtain third-party label-claim COAs:

• Amazon & retailer requirements. Many supplement categories on Amazon and major retailers now require third-party COAs. Without them, listings can be removed.
• FDA GMP documentation. FDA GMP requires manufacturers to maintain testing records. Third-party COAs create a defensible documentation trail that your own lab results cannot.
• Class-action lawsuit protection. Label-claim lawsuits are common in the supplement industry. A third-party COA showing accurate label claims is your primary defense.
• Consumer trust and brand premium. Brands that display third-party COA verification consistently command higher prices and lower return rates than untested alternatives.
• Ingredient-supplier QC. Even if your contract manufacturer is reputable, testing incoming raw materials and finished products ensures supplier accountability.

Ready to test? See our full supplement-testing scope or jump straight to the online intake form.