[2] The hormone NAA does not occur naturally, and, like all auxins, is toxic to plants at high concentrations.

In the United States, under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), products containing NAA require registration with the Environmental Protection Agency (EPA) as pesticides.

[3] NAA has been shown to greatly increase cellulose fiber formation in plants when paired with another phytohormone called gibberellic acid.

Because it is in the auxin family it has also been understood to prevent premature dropping and thinning of fruits from stems.

It is prohibited in many areas to use it in high concentrations due to the health concerns towards humans and other animals.