This animal study examined thyroid histomorphometry in juvenile male Wistar rats after 2 weeks of 5G EMF exposure (3.5 GHz, 1.5 V/m). Exposed rats showed larger follicle and colloid areas and a significantly lower Thyroid Activation Index, which the authors interpret as thyroid hypoactivity. The authors suggest this may represent a potential health risk and call for further work including hormone assays and mechanistic studies.