Certifications explained
Certwell surfaces products certified by four independent bodies. Each requires manufacturers to submit products for testing — certification is not self-declared.
Important: absence of certification does not mean a product is unsafe. It means the product has not been independently verified by one of these bodies. Many good products are not certified. Certification adds assurance — it is not a requirement for a safe supplement.
NSF Certified for Sport
NSF International is a US-based independent testing organisation. NSF Certified for Sport verifies that a product contains what the label says, does not contain unsafe levels of contaminants (including heavy metals), and is free from substances banned by major sports organisations.
Why it matters: Widely recognised by professional sports bodies and athletes. A strong signal for anyone buying protein powders, creatine, or sports supplements.
USP Verified
The US Pharmacopeia (USP) is a scientific non-profit that sets quality standards for medicines and supplements. USP Verified confirms that a product contains the ingredients listed on the label at the stated potency, is free from harmful levels of contaminants, and is made to good manufacturing practices.
Why it matters: One of the most established standards for vitamins and dietary supplements. Particularly relevant for everyday supplements like vitamin D, magnesium, and multivitamins.
Informed Sport
Informed Sport is a global quality assurance programme run by LGC, a UK-based science organisation. Every batch of a certified product is tested for substances on the World Anti-Doping Agency (WADA) prohibited list.
Why it matters: The UK-native standard. Especially relevant for sports supplements. Batch-level testing means the specific product you buy has been tested, not just the formula.
IFOS
The International Fish Oil Standards (IFOS) programme, run by Nutrasource, tests fish oil supplements for purity (PCBs, dioxins, heavy metals), potency (omega-3 content), and oxidation (freshness).
Why it matters: Fish oil is one of the most adulterated and mislabelled supplement categories. IFOS certification is the clearest signal of a high-quality fish oil product.