This product is assigned a retest date of approximately 4 years from the date of Quality release. Products that, while considered stable, may be subject to degradation over time are assigned a periodic retest date to confirm quality. The lot specific retest date is reported on the Certificate of Analysis.
Please see the link below to review a sample or lot-specific Certificate:
https://www.sigmaaldrich.com/product/sigma/u3750#product-documentation
