ThirdLove's cotton T-shirt bra is so comfortable you'll forget you're wearing it — here's how it's held up after one year of testing

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ThirdLove

• ThirdLove, a digitally native startup known for offering half-cup sizes, launched its first cotton collection in 2018.
• Five women on the Insider Reviews team tested the 24/7 Cotton T-Shirt Bra ($68) to see how it stacks up, and shared how the bras have held up over one year of use.
• In general, it's a great T-shirt bra: Soft, supportive, and comfortable enough to forget you have it on. Over time, it holds up pretty well — though we'd recommend the Cotton Plunge Bra ($68) for anyone who's concerned about the band below the keyhole detail rolling or creasing.
• The 24/7 Cotton T-Shirt Bra is available in four colors, band sizes 30-48, and cup sizes A-I, and underwear is available in sizes XS - 3X (00 - 24).
• Three classic shades are priced at $68, while five darker colors of the 24/7 Cotton T-Shirt Bra are currently on sale for $58.

ThirdLove — a women-led startup known for introducing half-cup sizes into the mainstream — has been one of the Insider Reviews team's go-to recommendation for lingerie since its inception. In an extensive testing process, we ranked it #1 in both our definitive buying guide to the best bras you can buy and the best strapless bra you can buy.

The reason why is simple: ThirdLove bras are a rare combination of affordability, comfort, style, and intuitive design that makes for a huge improvement on the standard options. Shopping here also includes the often invaluable perk of an energetic customer service team and a 100% fit guarantee. (If you take the company's Fit Finder and order the wrong size, ThirdLove will work to get you into the perfect fit at no further cost, donating the bras you don't keep to a women's shelter if necessary).

The company has also expanded to carry 70 sizes — well beyond the industry average of 30 — which racked up a waiting list of 1.3 million women upon its initial launch.

And finally, at the repeated request of customers, ThirdLove introduced its first-ever Cotton Collection in 2018 — made from super-soft, breathable Pima cotton that's perfect for all-day wear. Pima cotton, used to create underwear by other cult-favorite startups like Everlane, is a smoother, softer, and more durable variety of cotton thanks to 50% longer fibers. It retains its shape, doesn't pill, and feels light against the skin.

As an online company, ThirdLove relies upon millions of data points from customer feedback to engineer its new products — and for the last four years, one request has been constant: A cotton bra that women can live in. For the last two years, ThirdLove has been designing its response.

The finished product has ultra-thin memory foam cups, two-way convertible straps (worn either straight or crisscrossed), gold alloy strap adjusters, and a keyhole detail. The band has a subtle sheen, and the foam-padded hook-and-eye closure is tagless for a comfortable, scratch-free wear all day.

To give you an idea of what the 24/7 Cotton T-Shirt Bra is like in real life, five women on the Insider Reviews team tested it out. Below, you can find our verdict. If you'd rather skip to shopping, the short version is this: It's breathable, soft to the touch, and you might even forget it's on. The design is basic, but that's fine with us for a T-shirt bra this comfortable.

The 24/7 Cotton T-Shirt Bra is available in four colors, band sizes 30-48, and cup sizes A-I, and underwear is available in sizes XS - 3X (00 - 24).