Undershirt?

Highly recommend “Mr. Davis Comfort Fit Premium Bamboo Viscose Tailored Cut V Neck Men's Undershirt” I wear an M shirt size and I got a size S which fit nice and snug. The tan color is nice because it’s pretty much invisible through an undershirt. This undershirt makes wearing a dress shirt super comfortable.

I don’t recommend the usual classic tank top because it doesn’t cover the armpit area and most are usually thick and noticeable through a dress shirt.

Me personally no undershirts I use dove spray and don't sweat

I sweat a decent amount and have found that the Armani undershirts are a good weight and breathe well. Used to use brooks brothers but they come with too much fabric and don’t breathe as well.

.

I usually buy some simple t-shirts at primark with a wide v-neck and change every 6 months to a year, after the armpits starts to get some stains

I wear Thompson Tees because I sweat a lot for whatever reason. Only way I’m able to wear any shirt, period. They’re more expensive than most undershirts, but they really keep you dry and save your shirts.

No undershirt for me under my dress shirts.

Wallmart brand

I’ve been a Mr. Davis vneck guy for a while but just ordered a Uniqlo airism vneck based on the recommendations here. Will try to remember to report back.

For minimal visibility, I’d go with lightweight, close-to-skin crew necks in a nude or heather grey tone—those blend in better than white. Tank tops work if you're mainly after sweat control, but they don’t help much with transparency under dress shirts. I’ve had good luck with basics from brands like Leveret Clothing, they’re simple, breathable, and hold up well after washes.