If you can't wear a bra, look for a shirt that's made with stretchy, compressive fabric. This can help provide light support.
Nipple covers are a great non-bra option if you're looking for modesty. Boob tape is another bra alternative that can provide excellent support in a number of styles that you can customize to your body.
Shop Honeylove Bras
CrossOver Bra Wireless Bra
Honeylove's criss-cross mesh adds a signature touch, and a bonded underbust lifts without underwire. A wide wing with back-smoothing fabric eliminates back bulges. Adjustable straps and back let you modify your fit, and the straps can also be crisscrossed to stay hidden under racerback tank tops.
3D printed velvet adds support, and a bonded underbust lifts without underwire. Adjustable straps and back closure let you modify your fit. Straps can also be crisscrossed to stay hidden under racerback tank tops.