Thirdlove vs. Knix: Soft & Comfy Comparison (And Winner)

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Alison Huff

Alison Huff is a writer, editor, and mom with a passion for body positivity and personal style. With years of editorial experience and a research-driven perspective, she shares thoughtful reviews of everyday essentials that help readers feel more comfortable and confident in what they wear. She loves helping women embrace their style in a way that feels true to them, no matter their size or shape.

Latest posts by Alison Huff (see all)

• Thirdlove vs. Knix: Soft & Comfy Comparison (And Winner) - May 8, 2026
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• Thirdlove vs. Shapermint: Which Wireless Bra Is the Winner? - January 22, 2026

I have a pretty long list of “wants” whenever I go bra shopping. I want something comfortable enough that I’m not counting down the minutes until I take it off, but I also want support, shaping, and smoothing that looks good (or disappears) under clothing.

It’s a tall order, I know, but I think a lot of us are trying to find the same thing. You want to feel put together and supported, but you’re not willing to “suffer” through painful underwires or stiff padding just because a bra looks good.

During my hunt for the “perfect” bra for my fussy body, I tried wireless models from Thirdlove and Knix, since both care a lot about softness, stretch, and comfort.

Thirdlove & Knix (At a Glance)

I can say right out of the gate that both bra brands offer a lot in terms of softness and comfort, and I’ll tell you everything there is to know about my experience with both (and which one I preferred in the end).

My Experience With Bras From Thirdlove

I’m heavier-chested so smoothing is probably my number one priority, followed by comfort. I actually spend a lot of time not wearing a bra at all (working from home, FTW!) so whenever I’m actually wearing one, I’m hyper-aware of its presence on my body until the moment I take it off.

I chose the Comfort Stretch Smoothing Wireless Bra since it’s wireless and designed for smoothing, in “Dreamy Lilac,” a soft misty purple that feels like spring.

Although you’ll enter your band and cup size when ordering, Thirdlove translates that into its trademarked Precise Size, which is a conversion that helps to accommodate half-cup sizing or breast asymmetry. I normally wear a 38 G, which translates to XL++.

Every inch of the Comfort Stretch material feels super soft (inside and out!), including the straps, and the seaming is equally soft and does not irritate my sensitive skin. But what I appreciate the most about this particular bra is how well it smooths and contains the sideboob and underarm areas. Along the outer edge of each cup, there’s an extra fabric panel that extends higher than most bras provide, so everything stays contained and shaped really well beneath clothing, without spillage.

Although it’s completely wireless, the cups have foam shaping that adds just enough coverage to prevent nipple visibility without adding any bulk to your overall breast size. (Truth be told, I get really frustrated with bras that have so much padding they add to your cup size. I get the preference, and that can be nice when you want it, but when you don’t… that’s another story.)

I also appreciate that the Comfort Stretch wireless bra has detachable back straps so you can wear it racerback under tops or dresses when you need to. I live in the Midwest and summers get hot and humid; tank-tops are my go-to, and many of my faves have that “X” shape from the shoulder to mid-back. This bra stays invisible beneath them.

It might be an age thing, or it might just be an I-don’t-wear-a-bra-most-days thing, but I’ve come to loathe bras with an underwire unless I absolutely need to wear one under a specific outfit. For me, Thirdlove’s wireless Comfort Stretch is one of the few bras I can comfortably wear for extended periods, and even all day, without feeling eager to get out of it.

The lift it provides, even without an underwire in place, is pretty impressive… and this is coming from someone with a larger, heavier bust. I don’t look saggy beneath clothing; my shape is natural, smooth, and flattering no matter what I’m wearing.

It takes a lot for me to say that any bra is comfortable; it’s a pretty high bar, but Thirdlove hits it. 

Pros & Cons Of Bras From Thirdlove

While I’m a fan of Thirdlove for quite a few reasons, no bra brand is perfect, and it’s a good idea to consider the pros and cons before you shop.

Pros of Thirdlove Bras:

• Bras are a core focus at Thirdlove and they offer styles that include wireless, t-shirt, push-up, full-coverage, minimizer, unlined, plunge, front closure, racerback, sports, nursing, post-surgery/adaptive, and multi-way.
• They offer half-cup sizing, and their band/cup measurements translate into a trademarked Precise Size that, in my experience at least, delivers accurate fitting when you’ve taken your measurements beforehand. (Always take your measurements, even when you think you know your bra size. It can and does fluctuate.)
• Thirdlove offers a broader range of bra sizes compared to Knix, with cup sizes from AA to H/I and band sizes from 30 to 48.
• With their exceptionally soft fabrics and smart designs, Thirdlove bras provide support, lift, and shaping that’s actually comfortable and won’t irritate your skin, even during all-day wear.
• Despite the fabric being on the stretchier side, Thirdlove bras don’t lose their shape over time. (Pro tip: always air-dry after washing.) 
• If your bra purchase doesn’t fit just right, you have 60 days for a free exchange, as long as the tags are still on. 

Cons of Thirdlove Bras:

• Compared to some other brands, the selection of skin-tone shades (tans and browns in particular) is generally less extensive.
• Limited edition colors don’t last long so if you find a bra that has a color you fell in love with, I’d snag it sooner rather than later.
• Although the exchanges are free within 60 days (with tags on), any returns will include a $4.99 processing fee, but that’s avoided if you’re a Hooked Rewards Platinum member.

My Experience With Bras From Knix

When shopping for bras at Knix, I primarily wanted to find something as close to what I got from Thirdlove: wireless support, full coverage, and smoothing. I opted for the Revolution Busty Bra in “Rose Water,” a soft pink. (Apparently, I’m in my pastel phase.)

There are actually a few similarities to note with this bra, compared to the ComfortStretch I got from Thirdlove. Both are made from truly soft material that’s smooth and non-irritating, and the straps are on the thicker side so weight is distributed nicely without a lot of shoulder-digging.

Although the straps of the ComfortStretch are a bit more padded overall, the inside material on the Revolution Busty Bra straps is super soft, despite having very fine “ridges” along the material. (I promise, it looks textured in the photo, but it’s silky soft to the touch.)

This bra also has foam-molded cups that offer great coverage without padding or extra bulk, and there’s no seaming on the inside of the bra. Everything is soft and smooth against your skin when you’re wearing it, and I think that even if your skin is really sensitive, this would likely be irritation-free.

The Revolution Busty Bra is smoothing, but the area along the side of each breast and beneath the underarm doesn’t come up quite as high as the comfort stretch. So if you’re looking for the option that provides the most sideboob control, the ComfortStretch is going to be the better of the two.

That said, the underarm area specifically is reinforced with banding that adds extra shaping and support.

I think the biggest issue that I had with this bra was the back clasp. The Revolution Busty Bra has a normal hook-and-eye closure, but it’s thin and, at least in my experience, unhooks a little too easily. In fact, when putting it on and hooking all three rows, one of the hooks will usually need reattachment (which then detaches another that I need to reattach… like a little game of “musical hooks.”)

Once it’s on, the tension around the ribcage will generally keep it hooked with no problem. It’s just the act of getting them to stay hooked until it’s in place that’s a bit of a challenge.

Overall, the Revolution Busty Bra is comfortable and I still wear it, but I prefer my ComfortStretch from Thirdlove more.

Pros & Cons Of Bras From Knix

Knix has a lot to offer when you’re about to go bra shopping, but there are pros and cons to consider before you do.

Pros of Knix Bras:

• Knix offers a variety of bra styles, including wireless, t-shirt, bralettes, sports bras, nursing/maternity bras, and surgical recovery bras.
• The fabric on the cups and the straps is incredibly soft, and at least with the Revolution Busty Bra, there are no seams on the inside.
• The material is breathable with a lot of stretch for adaptability.
• Like Thirdlove, Knix bras are designed for comfort, shaping, and smoothing.
• A variety of styles to choose from, whether you 
• Returns can be processed at Knix (within 30 days) regardless of whether the tags are still on the item (even if it’s been worn and washed), which not gonna lie… is a pretty rare thing in the lingerie world.

Cons of Knix Bras:

• Although Knix carries a range of bra styles, it’s not as extensive compared to Thirdlove, and Knix’s primary focus is not on bras, specifically. (It began with leakproof underwear in 2013.)
• As with Thirdlove, the skin tone shades at Knix are fairly limited.
• The cup and band size range (A to H cups, 28–44 bands) is limited compared to Thirdlove, and also does not include half-cup sizing. 
• The return period at Knix is only 30 days, compared to the 60-day returns and exchanges you get at Thirdlove.

The Final Verdict

Although Thirdlove and Knix both use incredibly soft material that is super skin-friendly, I find the structure and comfortable support to be better in Thirdlove’s product line. Speaking of product lines, Thirdlove offers a lot more in terms of style based on specific needs, so you’re more likely to find exactly what you’re looking for.

As someone who really cares about smoothing, in particular, Thirdlove just does a better job, especially with the ComfortStretch line. There’s more lift, more structure, and just a nicer silhouette that makes my clothing sit better overall.

I still wear both bras, but I reach for my bra from Thirdlove way more often.