A reader asks: "Do I need to wear an undershirt with my button-front shirts, and if I open up the shirt, is it okay to let the undershirt show?"
For most button-front shirts, and especially the dress shirt, you can certainly use an undershirt. There are several good reasons why. Primarily, the undershirt absorbs sweat and odor, keeping you cool and your shirt dry and sweat-stain free. (Conversely, when temperatures dip, it provides an added layer of warmth.) Secondly, it helps your shirt lie flat by smoothing out minor bumps and lumps on your man terrain, such as body hair and nipples. Thirdly, it camouflages: If your entire back is inked and you clock in at a conservative office, the undershirt is your ally.
The purpose of the undershirt is to keep you comfortable and looking clean, sharp and confident. Just avoid those boxy, beefy ones and go for the thinner, silkier versions that fit close to the body - the undershirt should support and streamline, not add extra bulk.
I personally think it's best to honor the undershirt as it was intended to be worn - under and hidden. And if a little must peek through, make sure the trimming on the neck is crisp, clean, and flat, like how it looks when it's brand new, or close to it. Also, please, PLEASE: No colored undershirts! This is not the place to play matchy-matchy. If you want to go that route, it shouldn't be an undershirt - it should be a t-shirt, and that's another subject altogether.
I recommend crewnecks under dress shirts, but only if you plan on keeping it buttoned all the way up, like when you wear a tie. Because it starts from the neck, the crew won't create any unsightly bumps or lines on the upper chest like a V-neck or tank top would. And if you're wearing a white or light-colored shirt, especially in thinner fabric that tends to show through, the crewneck is your best bet for the seamless, nipple-less effect.
That said, if you plan to open up your shirt a little, like undoing just the top button on the collar, wear a standard V-neck so you can show a little skin - isn't that the point? And if you want to go for that second button, wear undershirts that come in a deep V. As for the plunging neckline beyond that, well... you know how I feel about that.
Since tank tops provide the least amount of coverage, yet has a lot of lines that can show through under the shirt, I recommend them with short sleeves, patterns, or meatier fabrics that hold up well on their own.
Whether you choose to wear an undershirt is of course up to you. But for all its benefits, the undershirt is a critical, foundational component to your wardrobe that should not be underestimated. What feels right from the inside naturally looks right on the outside - too bad it's not always the other way around.
