The Natural Fiber Swaps Guide: Women's Basics
If you have followed me for a while, you know the basics drawer is where I started all of this. The tanks, tees, underwear, and socks you wear every single day sit against your skin for more hours than almost anything else you own, and most of them are polyester, nylon, or acrylic blends with a cotton wash on the label.
So this is the guide I wish existed when I started swapping: my actual basics, organized the way I shop them.
A quick note on how this guide works. Every category has up to three picks. The cleanest option 🌿 is the purest natural fiber version I can verify, usually organic and GOTS certified. My pick 🤎 is the one I actually wear and reach for. The budget pick 💲 is the most affordable option that still follows the rules: all natural fiber, with organic or OEKO-TEX certified cotton as the floor. Where a pick has a catch, like a synthetic lace trim or a nylon elastic, I say so right on the pick. No pick is perfect, but every trade off is on the table.
Bras
🤎 My pick: Cou Cou Intimates The Balconette, $65. This is the bra I wear constantly, linked here in the French Blue colorway. The cup fabric is 100% organic cotton pointelle with no padding and no underwire. The honest disclosure: the French lace trim is 90% polyamide and 10% elastane, so it is a cotton bra with a synthetic lace trim, not a fully natural garment.
Also from Cou Cou: The Petite Bra in Baby Pink Cotton Jersey. A softer, simpler Cou Cou option in the same cotton jersey family as their Baby Tee.
💲 The budget picks: Quince Organic Cotton Scoop Bralette, 2 pack and Pact Everyday Modern Scoop Bralette, 3 pack. Both are organic cotton bralettes at budget prices, and the Pact code CATHERINE20 takes 20% off.
Underwear
🌿 The cleanest option: Q for Quinn High Waist Brief, 2 pack. 95% organic cotton in the Natural colorway, dyed with plants instead of synthetic dyes.
💲 The budget pick: Pact Everyday High Rise Brief, 6 pack in Warm Neutrals. 95% GOTS certified organic cotton and 5% elastane, made in Fair Trade certified factories, and the code CATHERINE20 takes 20% off.
Thongs
Thongs get their own section because the construction is different and most "cotton" thongs are mostly nylon.
🌿🤎 The cleanest option and my pick: Oddobody Cotton Thong, $26. 100% organic pima cotton body, and the t-string seams are fully encased in cotton so nothing synthetic sits in the most sensitive spot. One disclosure that applies to the whole Oddobody range: the waistband and leg elastic is nylon covered in cotton. I wear a size Small or Medium in this brand and recommend sizing up for a comfortable fit.
🌿 Also a cleanest option: Q for Quinn Pointelle Thong. 100% organic cotton in a pointelle knit, if you want a true zero synthetic option.
💲 The budget pick: Pact Everyday Classic Fit Thong, 6 pack. 95% GOTS certified organic cotton and 5% elastane, currently on clearance in the 6 pack, and the code CATHERINE20 takes 20% off.
Tanks and Camis
🌿🤎 The cleanest option and my pick: Flore Flore tanks. Flore Flore is the tank brand all over my Basics page here on the site, and I am not going to rank the styles against each other because I rotate through all of them. They are 100% organic cotton in a heavy ribbed jersey, made in Portugal. The options in my collection: the Hillie, the Dewi in Black, and the Jill.
💲 The budget picks: Pact On The Go-To Rib V-Neck Shelf Bra Tank (GOTS certified organic cotton with a built in shelf bra) and Pact Perfect Rib Scoop Neck Tank (97% organic cotton and 3% elastane). The code CATHERINE20 takes 20% off both.
Tees
🌿 The cleanest option: Pact Softspun Essential Crewneck Tee, $24. 100% organic cotton, which is why this is the one category where Pact is the cleanest option and not the budget one. Note that the Softspun line is the 100% cotton one; Pact's other tee lines add elastane. This is great layering shirt for underneath sweaters. The code CATHERINE20 takes 20% off.
🤎 My pick: Cou Cou The Baby Tee, $48. 100% organic cotton jersey, a shrunken 90s fit with capped sleeves. This exact tee is already on my Basics page because I wear it that much.
More good options: Everlane The Box-Cut Tee in Essential Cotton and the Flore Flore Car Baby Tee. The Everlane is a boxy organic cotton tee at an easy price, and the Flore Flore Car is a ribbed organic cotton baby tee if you want the elevated version.
Sweatpants
🌿 The cleanest option: MATE the Label Organic Fleece Straight Leg Sweatpant, $128. 100% GOTS certified organic cotton fleece, no elastane at all, made in a Fair Trade factory.
🤎 My pick: Elwood Core Straight Leg Sweatpant, $90. This is the wide leg, straight leg version, not the jogger. 100% organic cotton brushed French terry. These are a very loose, oversized fit, which i prefer for lounging.
💲 The budget pick: Organic Basics Weekend Loose Fit Sweatpants, $89. 100% organic cotton in a 370 GSM peached terry with a lightly brushed interior, GOTS certified by Control Union.
Socks
Socks are the one category where I will defend a little bit of stretch. 100% cotton socks do exist, but honestly they just fall off your feet and lose their shape. You do need a little bit of spandex if you want that normal sock experience, and both of my picks below are honest about that.
🌿 The cleanest option: Q for Quinn Cotton Quarter Pacers, about $14. 97% organic cotton in a midweight quarter length, GOTS certified organic by Ecocert Greenlife. They make lots of different sock lengths too, so if quarter is not your length, the same sock comes in other cuts.
🤎 My pick: Double Soul Low Sock, $11. The short ankle length. Double Soul's socks vary in fiber makeup depending on the style; this low one is 85% organic cotton and 15% recycled nylon. What I actually love about them is that they are very squishy and comfortable, which is why they are my pick. The code CATHERINEL20 takes 20% off.
Slippers
Slippers are a buy once category. Almost everything under $40 is polyester fleece or memory foam, so there is no honest budget pick here and I am not going to pad the list with one.
🌿🤎 The cleanest option and my pick: East Perry The Everyday Slip-On, $119. Real shearling, meaning sheepskin with the wool still attached, tanned without harsh chemicals or heavy metals, with a leather and suede bottom. For the other picks in this category, look for 100% shearling or wool on the label and nothing else.
Pajamas
🌿 The cleanest option: Aizome Organic Loungewear, pants $99. From the same company as my cleanest sheets in the Home guide: organic cotton dyed only with plants, indigo, sumac, or matcha and pomegranate. Full honesty: the loungewear set is a crowdfunding pre-order right now rather than regular retail, so this is a back it and wait pick, not a ships tomorrow pick. The code CATHERINE10 takes 10% off.
🤎 My pick: The Sleep Code Organic Pima Cotton Long PJ Set, $138. 100% organic Pima cotton, made in Peru, linked here in the Cornflower Blue long set.
More options: Cou Cou's cotton jersey pajama pieces, The Pant and The Raglan. Mix and match pieces in the same organic cotton jersey as the Baby Tee.
💲 The budget pick: Quince Organic Cotton Pointelle Pajama Set, $65. Organic cotton pointelle.
Bikinis
I wrote a whole post on nontoxic bikinis already, because swim is the hardest category in this entire guide. Natural fibers absorb water and dry slowly, and every natural option still needs a small amount of stretch fiber to function. These are the picks that make that trade off honestly.
🌿 The cleanest option: Earth Cove Swim String Bikini Top. This is Pure Earth Collection's swim line under its new name and new site, Earth Cove. It is the same formula I have recommended before: 98% GOTS certified organic cotton and 2% lycra, and the lycra is free from PFAS and BPA. UPF 50+ from the density of the weave, with no chemical coating. Tops and bottoms are sold separately.
🤎 My pick: Layere. Layere works on a drop basis: one release a month, and it sells out. So if their store shows sold out when you click through, that is just the between drops window, not the brand being gone. Get on their list for the next release. They are still the benchmark I compare natural swim and active pieces against.
🤎 Also my pick: Natasha Tonic Bikini Top in Tonic Blue. A hemp and certified organic cotton blend with 4% lycra, made in Los Angeles. Hemp is naturally UV resistant and antimicrobial, which is why it works in swim better than almost any other natural fiber.
No budget pick in bikinis. A cheap natural fiber bikini that holds up in water does not really exist yet, and a synthetic one would break the point of the guide.
Activewear
🌿🤎 The cleanest option and my pick: Layere Organic Cotton Leggings, $118. 95% certified organic cotton and 5% spandex, no polyester or nylon, low impact dyes. Same drop model as above: Layere releases about once a month and sells out, so if these show sold out when you look, check back for the next drop. Their piped sports bra in the same fabric is $88 when it is part of a release.
🌿 Also a cleanest option: Live The Process Raw Cotton Ballet Legging, $125, an organic cotton interlock where the brand states the stretch itself is petroleum free and nothing synthetic touches the skin. The Jupiter Legging is the same raw cotton line in a different cut.
🤎 My second pick: Studio K Linea Leggings, $135. Studio K's core fabric is listed as 94% LENZING ECOVERO, which is a wood pulp fiber, and 6% recycled Lycra. More Studio K pieces in my collection: the Rib Halter Neck Top, the Mové Cami, and the 93' Low Rise Pants (code CATHERINE).
💲 The budget picks: Jungmaven Orosi Legging, $98 (61% organic cotton, 27% hemp, and 12% spandex; the spandex share is higher than the other picks and I am showing it on purpose) and Pact On The Go-To Pocket Legging, $38 (90% organic cotton and 10% spandex, GOTS certified and Fair Trade made, code CATHERINE20 for 20% off).
My Take
If you only swap three things from this whole list, swap the pieces that touch your skin the longest and the most often: your underwear, your sleepwear, and the socks and tees you live in daily. That is where the fiber actually matters, and it is exactly where the mainstream options are the most synthetic.
Everything here will keep evolving as brands release better natural options, especially in swim and activewear, where the honest answer is still "we are not fully there yet." I would rather show you the real trade offs than pretend a perfect version exists.
Prices checked October 2026 and labeled with what they cover. Some of the links in this post are affiliate links.