It's an age-old question. One your grandfather likely asked every summer as well. "Will wearing an undershirt really protect me from sweating through my shirt or will it just make me sweat even more?"
According to the best medical authorities, a cotton undershirt will indeed keep you cooler while serving as a barrier between any perspiration and your dress shirt.
A thin cotton layer will actually wick the sweat from your skin, which helps regulate body temperature. Plus, the fibers do create very small pockets of air—just enough to cool the skin slightly.
You don't want a thick, bulky undershirt. Nor do you want a crew neck peeking out from your oxford. We've tried countless brands over the years and our money's on Hanes' Tagless V-necks. Thin yet durable, they easily tuck under dress shirts but could stand on their own as well.