Best-by date

A best-by date is the manufacturer's statement of the date until which a product, stored as directed, is expected to remain within its labeled specifications.

It should rest on stability testing, in which samples are held under defined conditions and tested over time to see how quickly the actives degrade. Cannabinoids break down gradually and faster with heat, light and air, so the date is in effect a claim about how long the stated potency holds. Terms such as expiration, best before and use by are used with slightly different meanings but serve the same purpose on a hemp product.

For a reader, the date is found near the batch number and can be considered alongside the certificate of analysis, which reports content on a single test date. A product past its date is not necessarily unsafe, but its cannabinoid content is no longer supported by the manufacturer's data. Whether stability testing actually underlies the date is not visible on the label, and companies that have done the work are usually willing to say so.