I Tried Merino Wool Underwear for a Week, Here's My Honest Take on Flowool's Triangle Bra

I've been wanting to try a merino wool bra for a while now. I already own merino wool bike shorts that I love, and everything I'd heard about the fabric, naturally breathable, moisture-wicking, fast-drying, gentler on skin than synthetics, made me curious whether it would hold up in a bra too. When Flowool offered to send me their Triangle Bra to test and share my honest thoughts, I said yes immediately.

I wore it for a full week (and honestly, it's stayed in my regular rotation since), in the cinnamon colorway, made from their 100% merino wool Pure Collection fabric. Here's everything I loved, and everything I'd change.

First Impressions: It's Not What You'd Expect

Say "wool bra" to most people and the first word out of their mouth is "itchy." That was my assumption too. It's not. The fabric is genuinely soft, nothing like the scratchy wool sweaters you're picturing.

What I Loved

It handled a heat wave better than anything else in my drawer. The week I got this bra happened to line up with a brutal hot stretch, and I kept reaching for it without even thinking about it. It doesn't hold onto sweat or feel damp against your skin the way cotton or synthetic blends do in the heat. Merino wool is also naturally antimicrobial, which matters more to me than I expected. There's a real mental difference between feeling sweaty and feeling dirty, and this never crossed into the second category, even on the hottest days.

No tag, no problem. It's fully tagless, so there's nothing rubbing against your skin at the back. Small detail, big relief if you're someone who cuts tags out of everything (I am).

The hook closures actually adjust. Multiple hook positions let you loosen or tighten the band around your torso, which is a small feature that makes a real difference day to day.

Removable padding, and I mean it works. The padding is thick enough that you're not worried about headlights, but removable if you want a different feel. I wore it without the padding one evening and it might have been the most comfortable bra experience I've had. If you're looking for a lounging bra, this is it without the padding in.

Sizing, and why I landed on medium. I was genuinely stuck between sizes here. I have a smaller underbust but a larger bust, which meant I was worried the medium would run too big overall. In the end, medium was the right call: the bust area fit comfortably with zero side-boob situation, and while the underbust band runs a little bigger on me, it fits well on the smallest hook setting. I also tried the small, and while the underbust fit great, the bust area was too small, small enough that the straps kept popping off randomly, which was more worrisome than annoying.

What I'd Change

The straps are thinner than I expected, and I have mixed feelings. I normally prefer a thinner strap because it's easier to wear under sleeveless tops. But for someone with a larger chest, these felt like they crossed the line from "thin and sleek" to "not supportive enough." They have eased up and felt better over the past few weeks, but that first stretch of finding the right tightness was genuinely frustrating: too tight and they dug in, too loose and they felt like they'd slide right off my shoulders. I didn't feel as supported as I do in a thicker strap.

Adjustable straps: nice, but not essential for me. This is a "your mileage may vary" one. If you regularly switch between tops that need different strap lengths, you'll get real use out of this. I don't wear a lot of those styles, so for me it was a nice-to-have rather than a must-have.

The criss-cross feature needs a more secure hook. I liked the idea of the criss-cross styling option, but even in the medium, one of the hooks came loose from the eye while wearing it. The feature itself is a great idea, I just don't think the current hook construction holds it securely enough to trust it through a full day.

My real wish: the band of the small with the cup of the medium. If I could build my own version of this bra, that combination would be perfect. As it stands, I had to choose which compromise I was more comfortable with, and for me, comfortable cups won.

Padding: I'm torn. It does its job (no worrying about flashing anyone), but I noticed it makes my chest look noticeably bigger compared to wearing it without the padding in. Some people will love that. Personally, I'd prefer something a little thinner that reads more natural. This is genuinely a personal preference thing, not a flaw, just know it's there before you decide.

The Verdict

Would I recommend it? Yes, with the caveat that your fit experience really depends on your specific proportions. If you're someone with a smaller frame and more proportional bust-to-band ratio, I think this bra will feel close to perfect. If you're in the same in-between boat I was (smaller torso, larger bust), go in expecting to make a tradeoff, and lean toward sizing up for the cups over the band.

What kept me wearing it past the review period wasn't the styling features, it was how it performs in heat and how it feels against skin day to day. That's the merino wool doing exactly what merino wool does.