3-Nitrooxypropanol

3-Nitrooxypropanol, abbreviated 3-NOP or 3NOP, is an organic compound with the formula HOCH2CH2CH2ONO2. It is the mononitrate ester of 1,3-propanediol. The compound is an inhibitor of the enzyme methyl coenzyme M reductase (MCR). MCR catalyzes the final step in methanogenesis. When it is fed to ruminants, their methane production is diminished.

Bovaer®
3-NOP has been commercialised as a methane inhibitor for production animals. Bovaer® is a feed additive manufactured by DSM for cattle that claims to reduce methane emission from dairy and beef cattle by 30% and 45% respectively. It consists of silicon dioxide (60% w/w), propylene glycol, and 3-nitrooxypropanol (10% w/w).

In 2021 Bovaer® has been approved as a feed additive in Brazil, one of the world's largest meat exporters and also Chile. In 2022, it was approved for use on dairy cows in the EU. Recently in 2024, Bovaer has been approved in Canada as a cattle nutrition feed additive.

On April 27th 2022 DSM and Elanco Animal Health Inc. announced a strategic alliance where Elanco would gain exclusive licensing rights to develop, manufacture, and commercialize Bovaer® in U.S.A.

On June 8th 2023 Elanco US Inc requested a consultation with the CVM group of the US FDA to evaluate the drug status of Bovaer for use a methane inhibitor in dairy cows. On May 24th 2024 the FDA reported that they had finished evaluating safety and efficacy data for Bovaer. They concluded the product did reduce methane production when used as labelled and is expected to pose a low risk to animals and humans under the conditions of its sale. For the US FDA Bovaer remains an unapproved drug with specific conditions on manufacturing standards and adverse event reporting.