What if an existing Reference Standard is currently not available from USP?
The availability of USP Reference Standards is generally better than 99% and we strive to plan ahead to replace depleted lots in a timely manner. We project a depletion date for each Reference Standards lot based on historic trends. However, despite our best efforts, some Reference Standards might occasionally be out of stock temporarily. Contact your USP Account Manager or Reference Standards Technical Service to find out when the specific Reference Standards you’re looking for might become available again. You can also frequently check the product listings on USP’s e-store or sign up for our email notices, which will keep you informed about Reference Standards that become available. Send an email to if you’d like to sign up for the email notice service. You can place an order now for Reference Standards that are not currently in stock. Products that become available within 30 days of your order will automatically be shipped to you. If the products become available after 30 days, USP
