Thorne Supplements are 3rd-Party Contents Certified

Do you worry about the contents of the nutritional supplements you take?
Choosing a supplement that is third-party tested and certified gives you peace of mind. That’s why Thorne participates in third-party product certification to ensure the supplements that we manufacture have their contents tested and certified.
The certification mark on a supplement’s product label can simplify your decision. Supplements that bear a third-party contents certified mark have undergone a rigorous testing and evaluation process.
Whether you buy your supplements from the manufacturer or a retailer, look for the third-party contents certified mark on the label, so you can be confident you are taking a tested, safer supplement. Third-party certification is your assurance that the supplement has been tested by a respected and independent certification organization.
Thorne’s independent third-party certifier is NSF, which performs tests on Thorne supplements to verify what's in the package matches what's on the label and to confirm it contains no unsafe levels of contaminants, such as heavy metals, pesticides, and microorganisms. Supplements that pass these tests may bear the NSF Contents Certified mark.
What is NSF Contents Certified? How is it different from NSF Certified for Sport®? And why is product certification from a third-party safety organization necessary?
Nutritional supplements and the need for finished product certification
In 1994 there were 4,000 nutritional supplements on the U.S. market; by 2014, there were more than 90,000.1 According to NSF, in 2024 there are more than 15,000 nutritional supplement manufacturing facilities worldwide, with at least half of these facilities located outside the United States.
A recent report of nutritional supplement manufacturing facilities that are registered with the U.S. Food and Drug Administration (FDA) indicates that fewer than three percent of these facilities are audited on an annual basis.2 And when these facilities are audited, two-thirds are given significant quality violations, with many having multiple severe violations.
Given the fast pace at which many nutritional supplements manufacturers enter the marketplace and reporting that suggests some of their products don’t contain the ingredients or quantities shown on the label, consumers have cause to be concerned.
Thorne’s commitment to third-party certification from safety organizations like NSF enables consumers to make the best choices for their health without uncertainty.
About NSF
Founded in 1944, NSF is an independent and accredited non-governmental organization whose mission is to protect and improve global human health, helping people live safer by testing and certifying consumer products – including nutritional supplements.
NSF achieves this by facilitating the development of public health and safety standards and by testing and certifying products and systems to those standards. Deeply rooted in science, NSF is widely recognized as the “gold standard” for quality in such areas as water systems, food safety, and health sciences, including nutritional supplements.
NSF helped develop the only American National Standard for testing and certifying nutritional supplements, NSF/ANSI 173, and has tested and certified products to this standard since 2004.
Certified products earn the NSF mark, which is respected by consumers, manufacturers, retailers, and regulatory agencies. You can feel confident when you purchase a product that bears the NSF Contents Certified mark!
What Is NSF Contents Certified?
NSF Contents Certified is a product certification that delivers peace of mind to everyday consumers looking to improve and enhance their health and wellness.
The NSF Contents Certified program assesses the composition of nutritional supplements for compliance with label claims to verify that what’s in the container matches what’s on the label. NSF Contents Certified also reviews each product for the presence of microorganisms, pesticides, and contaminants that impact health, including toxic elements and heavy metals like lead, mercury, arsenic, and cadmium.
In addition, to be able to manufacture and market NSF Contents Certified supplements, manufacturers must be audited on-site by NSF to ensure they are compliant with FDA’s standards for good manufacturing practices.
To ensure Thorne supplements comply with NSF standards, NSF audits are repeated annually at Thorne’s manufacturing facility in Summerville, South Carolina.
What does NSF’s contents tested certification mean?
There are numerous quality components of the NSF Contents Certified program:
- The product is manufactured at a facility that is GMP-registered and is audited annually for quality and safety by NSF to comply with the FDA’s Good Manufacturing Practice (GMP) requirements.
- Toxicological review of the product label to ensure the ingredients are allowed to be in a nutritional supplement and that the amount of each ingredient does not exceed typical use levels established by NSF.
- The label is evaluated and the product is tested to verify product formulation and label claims to ensure that what is on the label is in the product. Finally, chemical and contaminant testing is conducted to ensure there are no potentially harmful levels of contaminants, pesticides, and heavy metals.
What does it take to be NSF Contents Certified?
Companies that pursue NSF’s Contents Certified certification go through these steps:
Step 1 – GMP Registration: This verifies that the supplement is manufactured, packaged, and stored in a facility that is audited annually for quality and safety in compliance with federal regulations for nutritional supplements GMPs. GMP registration includes:
- Audits of the production facilities that manufacture, package, warehouse, or distribute nutritional supplements
- Review of quality control testing procedures for raw materials and finished products
- Review of maintenance, housekeeping, cleaning, and sanitization procedures
- Review of sourcing and traceability procedures
- Review of training and qualification programs
- Review of internal standard operating procedures
- Review of product recall procedures
Step 2 – Contents Tested and Certified Certification: After step one is complete, NSF experts evaluate the supplement contents and then test the finished product to verify that it contains no unsafe levels of contaminants and meets the claims and contents shown on the product label.
Annual Laboratory Testing/Analysis
- Label content verification
- Contaminants
- Microbiological and heavy metals
- Pesticides/herbicides
- Protein and caffeine verification
- Disintegration testing
- Ongoing monitoring
- Review of formulation/supplier changes by NSF experts, including documentation and testing if justified
- NSF auditor review and confirmation of formulation at future GMP audits
- Ongoing annual testing of product for compliance
NSF Contents Certified versus NSF Certified for Sport®
You might be familiar with Thorne’s NSF Certified for Sport® program, which tests for the absence of more than 300 substances banned from competition by major athletic organizations. NSF Certified for Sport® applies to specific sports performance and foundational supplements that Thorne manufactures; these supplements are used by professional athletes who are tested regularly for performance-enhancing drugs.
Note: Although all Thorne supplements that are NSF Certified for Sport® will also be NSF Contents Certified, not all NSF Contents Certified supplements are NSF Certified for Sport®. To confirm your supplement’s certifications, look for the NSF certification marks on the product label.
Look for the NSF Contents Certified mark.
If you take a nutritional supplement that bears the NSF Contents Certified mark, then you can be confident that its contents have been thoroughly tested by one of the most respected certifiers in the world. Thorne’s commitment to third-party testing and certifications by NSF are part of the reason why thousands of health-care professionals and millions of customers worldwide choose Thorne.