Kirkland Signature

Kirkland Signature receives a brand trust score of 80/100 in GoodSupp's independent analysis. The company was founded in 1995 and is headquartered in Issaquah, Washington, United States. Our research did not find independently verified third-party certifications for this brand. While this doesn't mean their products are low quality, third-party testing is considered a strong indicator of commitment to quality assurance. Note: Kirkland Signature has 3 historical regulatory incidents on record. These are factored into the overall trust score and are detailed in the violation history section above.

GoodSupp's research did not find verified third-party testing certifications for Kirkland Signature. Third-party testing by organizations like NSF International, USP, or Informed Sport is considered one of the strongest indicators of supplement quality. Without it, consumers must rely more heavily on the brand's own quality claims. This doesn't necessarily mean Kirkland Signature's products are low quality, but it does mean there's less independent verification of their claims.

Based on GoodSupp's quality analysis, the highest-rated Kirkland Signature supplements are: Coenzyme Q10 100 mg (score: 100/100); Vitamin D3 1000 IU (score: 100/100); Magnesium Citrate 250 mg (score: 100/100). These scores are calculated from ingredient quality, dosage adequacy, bioavailability, label transparency, and inactive ingredient safety. Scores can vary significantly across a brand's product line — a high brand trust score doesn't guarantee every individual product is top-quality.

Kirkland Signature is headquartered in Issaquah, Washington, United States. The company was founded in 1995. They currently offer 56 products in their supplement lineup. Their official website is costco.com/kirkland-signature.html. Manufacturing location may differ from corporate headquarters — look for GMP certification to verify manufacturing quality standards.