u/Traditional-Wall7742

Recently had a couple of bouts with a friend where I didn't wear a long sleeve shirt under my fencing jacket, and realised my mistake afterwards because the sweat and tight fit caused it to suction fit to my arms so much I had to get help to take it off. Felt like a proper knight then, needing a squire to take off my kit.

But it did lead me to wonder about good and bad clothing for HEMA training, and I am curious:

What kind of shirts do you usually wear underneath your jackets? Are there certain brands you swear by or just generic? Cotton? Linen? Synthetic? Au naturelle? Baby powder?