Used as an intermediate and active pharmaceutical ingredient in the synthesis and formulation of various pharmaceuticals and fine chemicals. It is a sympathomimetic agent commonly employed in the production of amphetamine-type compounds, including appetite suppressants and decongestants such as phenylpropanolamine itself and related derivatives. Its reactivity makes it valuable in forming carbon-carbon bonds in specialized organic synthesis. Due to its structural similarity to controlled substances and potential health risks (e.g., stroke), its use is strictly monitored and regulated in many countries to prevent diversion into illicit drug production.