Because they comprise up to 90% of medications, the quality of inactive ingredients (excipients) is critical for a drug to be safe and effective. Our documentary standards provide the appropriate, validated test procedures to establish the identity, purity and quality of excipients, while our reference standards are authentic specimens that have been approved as suitable for use as comparison standards in USP or NF tests and assays. At every step, we're protecting the public's health by helping to prevent poor-quality medication from entering the marketplace.

In-focus: Get the latest excipient news

Excipient Standards Catalog

Excipient Standards Catalog

USP offers more than 350 expert curated and highly characterized Reference Standards. Explore excipients you can trust.


3rd LNP Summit , April 29 - May 1

Meet our team at LNP and join Dr. Sheehan's talk on our LNP solution approaches. 

LG polymer solutions

Want robust methods for LG polymer characterization? Explore our solutions.

Excipient World, May 13 - 15

Stop by our booth #107 to explore USP’s work supporting excipient quality and development.  

Novel excipients hub

Want updates on USP’s work on novel excipients? Plus, share your top novel excipient challenges with us.

Featured resources

Liquid excipients
Partner With Us

Contribute to the development of USP standards for Excipients

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DEG tool kit
DEG Tool Kit

Access USP’s free toolkit for measuring and controlling levels of Diethylene Glycol and Ethylene Glycol contamination.

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Harmonization of Excipient Standards - Pharmacopeial Discussion Group

Twice a year, USP, the Japanese Pharmacopoeia, and the European Pharmacopoeia convene to carry out the harmonization activities of the Pharmacopeial Discussion Group. Review highlights from the latest meetings.

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USP Public Policy Position

Excipients: A Blind Spot in Ensuring Medicine Quality and Supply Chain Resilience

Excipient quality issues and shortages have contributed to supply chain disruptions, drug shortages, and adverse patient health outcomes. Enhancing visibility into excipients supply chains is essential to properly focus efforts to prevent or mitigate drug shortages.

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Fostering the Use of Novel Excipients in Drug Products

USP supports policies and initiatives to facilitate the introduction and use of novel excipients that encourage increased cooperation and coordination between stakeholders and prioritize regulatory developments to support their use in new therapies and modalities.

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