Skip to main content
U.S. flag

An official website of the United States government

Here’s how you know

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

This is a preview of updates coming to the Technical Bulletin's website in April 2026. Return to current site.
Read more about the modernization release schedule in this announcement.
Comment via the yellow feedback button in the lower right hand corner of the page. Contact the NLM Help Desk with any questions or concerns.

This is archived content.

Links may have become inactive over time. Visit Archive-It   to find the original published layout.

FDA Substance Registration System to Move from NLM to FDA

FDA Substance Registration System to Move from NLM to FDA. NLM Tech Bull. 2021 Nov-Dec;(443):e4.

November 19, 2021 [posted]
December 17, 2021 [updated]

[Update: On December 17, 2021, this article was updated with the link to the new FDA-hosted site.]

In December 2021, the FDA Substance Registration System (FDA SRS) will move from the National Library of Medicine (NLM) to the U.S. Food and Drug Administration. FDA SRS is a resource for searching and downloading Unique Ingredient Identifiers (UNIIs) representing over 120,000 substances in FDA-regulated products. The new FDA-hosted site is accessible now, and links referencing the NLM site will begin redirecting to the new site soon. Please update your links and bookmarks with the new SRS link: https://precision.fda.gov/uniisearch.

If you have any questions, please contact the NLM Support Center.