Naphthylacetic acid is an acetic acid substituted with a naphthyl radical. As is the case with other aromatic substituted acetic acids, it displays an effect in plants that is analogous to auxins. Auxins are a group of natural and synthetic growth regulators that have diverse effects on growth and differentiation processes. One common and naturally occurring auxin is indole-3-acetic acid. Naphthylacetic acid is structurally related to indole-3-acetic acid and displays the same effect as the natural auxin, which is why it is used as a synthetic phytohormone in plant protection protects.

One application for naphthylacetic acid is in vegetative reproduction, where it helps facilitate optimal fruit size and higher quality fruit. Additionally, using naphthylacetic acid can help prevent fruit from falling prematurely and therefore also minimize fruit thinning.

The use of naphthylacetic acid is permitted in the European Union (EU). The Regulation (EC) No 396/2005 defines the permitted maximum levels.

The GBA Group carries out the analysis of naphthylacetic acid by means of HPLC-FLD technology. If you would like to have your food tested, we are gladly available to assist you.

**Sources: **
https://eur-lex.europa.eu/legal-content/EN/ALL/?uri=CELEX%3A32005R0396