SUPPLEMENT SCIENCEInsights
Search

Search Insights

Try choline, nano-curcumin or probiotics.

    Ingredient guide · Ingredient reference

    Are NOW supplements third-party tested? Internal and external checks differ

    NOW reports both in-house testing and work with outside laboratories. That does not make every quality claim a public, independently verified test of every lot.

    Read the evidence ↓

    Supplement Science Insights Editorial Team

    Published September 23, 2026

    What the manufacturer reports

    NOW’s published testing information describes internal laboratory work and outside partners for specialized tests, duplicate verification and certifications. This is a manufacturer account of its program. It should be distinguished from a certificate or laboratory result obtained for the bottle being evaluated. [1]

    Different seals apply to different scopes

    The company’s certification information distinguishes manufacturing-system certification from product-specific marks. A laboratory accreditation, a facility audit and a finished-product contaminant panel answer different questions. None alone proves that every conceivable contaminant is absent or that the supplement works clinically. [2][3]

    Make a product-level check

    Imagine a NOW product advertises a sports certification. Match its exact name and version to the certifier’s current listing and, where available, the lot record. For another NOW product without that mark, do not transfer the certification just because the brand is the same. [2][3]

    Hypothetical example — separate the kind of assurance from the claim
    EvidenceWhat it can establish
    In-house testingManufacturer laboratory work
    Outside-lab testingA defined external test
    Certification on another productDoes not transfer automatically
    Are NOW supplements third-party tested? Internal and external checks differ — original article outline diagram
    Original editorial diagram of this article’s sections; no product photograph or clinical finding is depicted.

    Sources for this article

    1. NOW Comprehensive Testing
      Source consulted: 2026-09-20. This is a reference resource, not a claim that we conducted the studies or tested a product.
    2. NOW Seals and Certifications
      Source consulted: 2026-09-20. This is a reference resource, not a claim that we conducted the studies or tested a product.
    3. Dietary Supplement and Vitamin Certification | NSF
      Source consulted: 2026-09-20. This is a reference resource, not a claim that we conducted the studies or tested a product.