Moisture-Wicking

Wicking only does anything if the moisture it moves to the surface can then evaporate, which needs moving air and a room that is not already saturated. In a breeze or a ventilated gym it works exactly as advertised. Under a jacket, in a humid room, or sitting still on a hot day, the water arrives at the surface and stays there, and the shirt feels no better than cotton would. Choose it for activity with airflow, not for heat on its own.