NSF Certified for Sport
Also known as: NSF Sport, NSF International for Sport
A US-based supplement certification (NSF International) confirming the product is tested for banned substances and label-accurate ingredient content.
NSF Certified for Sport is one of the two leading independent supplement certifications (the other being Informed Sport). The program tests products against more than 270 substances banned by major sports organizations including the NFL, MLB, NHL, PGA, LPGA, CFL, and WADA. Products that pass earn the NSF Certified for Sport seal and are listed in the official NSF database.
The certification covers more than just banned substances. NSF also verifies that the label content matches what is in the product — the listed grams of protein, creatine, or vitamins are actually there in the listed amounts. This guards against the long-running industry problem of products under-dosing the active ingredient.
For anyone subject to professional or collegiate drug testing in North America, NSF Certified for Sport is the most common certification to look for. The product database is searchable at nsfsport.com. For non-tested recreational users, the seal is a strong general quality marker but not strictly necessary.