The Simple Folk
July 18, 2026
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The Simple Folk sustainability review: the real plant fibre percentage and natural score, tested by label to the Throne Standard. See the data.
Tap any fibre we measure. See its class and whether it’s in Sustain by Kat, instantly, the same engine that scores every brand in the app.
The headline breakdown, then every product read fibre by fibre, no sampling.
| # | Style | Composition | Class |
|---|---|---|---|
| 01 | Ayurvedically-dyed Shorts – Sustain by Kat | — | Plant |
| 02 | Undyed Linen Tee – Sustain by Kat | — | Plant |
| 03 | Snow White – Sustain by Kat | — | Plant |
| 04 | Oh My Deer – Sustain by Kat | 100% organic cotton | Plant |
| 05 | Undyed Organic Racerback – Sustain by Kat | — | Plant |
| 06 | Ayurvedically-dyed Indigo – Sustain by Kat | — | Plant |
| 07 | La La Lace Tank – Sustain by Kat | — | Plant |
| 08 | Plant-dyed Harem Pants – Sustain by Kat | 65% organic cotton and 35% natural rubber | Plant |
| 09 | Written with Walnuts Classic Racerback – Sustain by Kat | — | Plant |
| 10 | Organic Indigo Leaf Dyed Jean Shorts – Sustain by Kat | — | Plant |
| 11 | Colorgrown Cotton Tee – Sustain by Kat | 100% organic cotton | Plant |
| 12 | Undyed Organic PJ Cami – Sustain by Kat | — | Plant |
| 13 | Plant-dyed Shibori Tee – Sustain by Kat | — | Plant |
| 14 | Plant-dyed Scarf – Sustain by Kat | — | Plant |
| 15 | Christmas Tree Long Sleeve Onesie – Sustain by Kat | — | Plant |
| 16 | Snowman Long Sleeve Onesie – Sustain by Kat | — | Plant |
| 17 | Plant-dyed Silk Hair Ties – Sustain by Kat | 65% organic cotton | Plant |
| 18 | Organic Cotton Cord – Sustain by Kat | 100% organic cotton | Plant |
| 19 | Organic Cotton Lace – Sustain by Kat | 100% certified organic cotton | Plant |
| 20 | Indigo Swirl Kids Long Sleeve – Sustain by Kat | — | Plant |
| 21 | Kids Sunburst Tee – Sustain by Kat | — | Plant |
| 22 | Organic Cotton Fabric – Sustain by Kat | 100% GOTS certified organic cotton | Plant |
| 23 | Organic Colorgrown Cotton Fabric – Sustain by Kat | 100% GOTS certified organic cotton | Plant |
| 24 | Organic Colorgrown Cotton Fabric – Sustain by Kat | 100% GOTS certified organic cotton | Plant |
| 25 | Organic Indigo-Dyed Denim Fabric – Sustain by Kat | 100% GOTS certified organic cotton | Plant |
| 26 | Undyed Organic Makeup Remover Pads – Sustain by Kat | 100% undyed, chemical free organic cotton | Plant |
| 27 | Kids Organic Plant-dyed Shibori Dress – Sustain by Kat | — | Plant |
| 28 | Kids Organic Plant-dyed Shibori Dress – Sustain by Kat | — | Plant |
| 29 | Avocado-dyed Shibori Tee – Sustain by Kat | — | Plant |
| 30 | Organic Weld Seeds – Sustain by Kat | — | Plant |
| 31 | Plant-dyed Silk Hair Tie Minis – Sustain by Kat | 65% organic cotton | Plant |
| 32 | Kids Organic Plant-dyed Leggings – Sustain by Kat | 65% certified organic cotton and 35% natural rubber | Plant |
| 33 | Plant-dyed Muscles & Lace – Sustain by Kat | — | Plant |
| 34 | Kids Organic Colorgrown Leggings – Sustain by Kat | 100% organic cotton | Plant |
| 35 | Ayurvedic Cami – Sustain by Kat | — | Plant |
| 36 | Organic Cotton / Natural Rubber Elastic (Various Widths) – Sustain by Kat | 65% certified organic cotton and 35-40% natural rubber | Plant |
| 37 | Naturally-dyed Colorblock Top – Sustain by Kat | — | Plant |
| 38 | Plant-dyed Tunic – Sustain by Kat | — | Plant |
| 39 | Organic Linen Handkerchiefs – Sustain by Kat | 100% gots certified organic linen | Plant |
| 40 | Organic Silk Eye Mask – Sustain by Kat | 60% certified organic cotton and 40% natural rubber | Plant |
| 41 | California Grown Plant-dyed Linen Tee – Sustain by Kat | — | Plant |
| 42 | Plant-dyed Racerback – Sustain by Kat | — | Plant |
| 43 | Plant-dyed Linen Tee – Sustain by Kat | — | Plant |
| 44 | Lavender & Chamomile Dyed Cami – Sustain by Kat | — | Plant |
| 45 | Lavender & Chamomile Dyed Shorts – Sustain by Kat | — | Plant |
| 46 | Undyed Organic PJ Shorts – Sustain by Kat | — | Plant |
| 47 | Kids Starry Night Organic Sweatshirt – Sustain by Kat | 100% organic cotton | Plant |
| 48 | Plant-dyed Organic Cotton Thread – Sustain by Kat | — | Plant |
| 49 | Undyed Organic Cotton Thread – Sustain by Kat | — | Plant |
| 50 | Kids Shibori Purple Organic Sweatshirt – Sustain by Kat | 100% organic cotton | Plant |
| 51 | Kids Organic Plant-dyed Shibori Dress – Sustain by Kat | — | Plant |
| 52 | Kids Shibori Tee – Sustain by Kat | — | Plant |
| 53 | Kids Organic Plant-dyed Shibori Dress – Sustain by Kat | — | Plant |
| 54 | Plant-dyed Silk Scrunchies – Sustain by Kat | 100% organic silk | Animal |
| 55 | Kids Organic Plant-dyed Shibori Dress – Sustain by Kat | — | Plant |
| 56 | Plant-dyed Scarf – Sustain by Kat | — | Plant |
| 57 | Plant-dyed Scarf – Sustain by Kat | — | Plant |
| 58 | Plant-dyed Scarf – Sustain by Kat | — | Plant |
| 59 | Plant-dyed Scarf – Sustain by Kat | — | Plant |
| 60 | Plant-dyed Scarf – Sustain by Kat | — | Plant |
| 61 | Plant-dyed Scarf – Sustain by Kat | — | Plant |
| 62 | Plant-dyed Scarf – Sustain by Kat | — | Plant |
| 63 | Plant-dyed Scarf – Sustain by Kat | — | Plant |
| 64 | Plant-dyed Scarf – Sustain by Kat | — | Plant |
| 65 | Plant-dyed Organic Sewing Thread – Sustain by Kat | 100% gots certified organic cotton | Plant |
| 66 | Plant-Based Lake Pigments – Sustain by Kat | — | Plant |
| 67 | Mini Plant-dyed Silk Scrunchies – Sustain by Kat | 100% organic silk | Animal |
| 68 | Indigo Organic Cotton/Linen Napkins – Sustain by Kat | — | Plant |
| 69 | Indigo Organic Cotton/Linen Dish Towels – Sustain by Kat | — | Plant |
| 70 | Indigo Organic Cotton/Linen Tea Towels – Sustain by Kat | — | Plant |
| 71 | Specialty Organic Cotton / Natural Rubber Elastic – Sustain by Kat | 65% certified organic cotton and 35-40% natural rubber | Plant |
| 72 | Organic Plant-Dyed Fabric - Indigo Stripes – Sustain by Kat | 100% organic cotton | Plant |
| 73 | Organic Plant-Dyed Fabric - Indigo Plaid – Sustain by Kat | 100% organic cotton | Plant |
| 74 | Organic Plant-Dyed Fabric - Green Squares – Sustain by Kat | 100% organic cotton | Plant |
| 75 | Organic Plant-Dyed Fabric - Charcoal Gray – Sustain by Kat | 100% organic cotton | Plant |
| 76 | Organic Plant-Dyed Fabric - Lavender Houndstooth – Sustain by Kat | 100% organic cotton | Plant |
| 77 | Organic Plant-Dyed Fabric - Multicolor Stripes – Sustain by Kat | 100% organic cotton | Plant |
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| Brand | 4Sustain by KatYou’re viewing |
5Where Does It Come From? | 5The Classic T-Shirt Company | 5Momotaro Jeans | ＋ |
|---|---|---|---|---|---|
| Fibre score | 4 / 5 | 5 / 5 | 5 / 5 | 5 / 5 | |
| Plant fibre | 931% | 100% | 100% | 100% | |
| Synthetic | 0% | 0% | 0% | 0% | |
| Styles scanned | 77 | 89 | 38 | 44 | |
| GOTS | Yes | — | Yes | — | |
| Cotton origin | Not disclosed by country | India | India | Zimbabwe (many flagship models… |
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Sustain by Kat, a small Los Angeles brand founded in 2016, uses GOTS certified organic cotton and 100% plant-based natural dyes, and states every garment component (down to elastic and thread) is organic. Good On You rates it ‘Good’ (Planet 4/5, People 3/5, Animals 4/5) and notes it partly traces its supply chain including the final and some second production stages. However, Sustain by Kat does not publish an aggregate supplier breakdown or a named factory list, and there is no evidence of living-wage assurance.
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DOCUMENTED (corroborated by brand + independent sources): founding 2016 in Los Angeles by Kat Quigley; LA manufacturing; use of GOTS-certified organic cotton fabric/thread/labels; use of plant and mineral-based dyes (e.g. pomegranate); silk used but no leather, wool or fur; slow/small-batch model. MARKETING CLAIMS NOT INDEPENDENTLY VERIFIED: the brand's "fair wages and safe working conditions acro
Sustain by Kat garments are made in Los Angeles, California, USA. The brand and multiple third-party sources state fabric is sewn into clothing in Los Angeles by a small manufacturer, and product pages carry the line "Ethically designed and manufactured in Los Angeles." Some inputs (such as the naturally dyed sewing thread) are produced in-house by the founder, and some handwoven fabric is sourced via a nonprofit charitable trust. The country of origin of the raw organic cotton fibre itself is not publicly documented.
Sustain by Kat was founded in 2016 in Los Angeles, California by Katherine "Kat" Quigley, who owns and runs it as an independent, founder-led brand with no parent company documented. Quigley holds a B.S. in Biology and an M.S. in biomedical engineering, and is described as founder and CEO; she was motivated during her first pregnancy by concern over chemicals absorbed through clothing. No investor or corporate owner is publicly documented, so the brand appears to be independently owned.
Sustain by Kat is a real, currently-trading legitimate business operating at sustainbykat.com with an active shop, product catalogue (womenswear, kidswear, accessories, fabric) and account/checkout functionality as of mid-2026. It is independently rated "Good" by Good On You and Sustainable Review, and listed on SustainabilityTracker and CommonShare, confirming it is the genuine Los Angeles plant-dyed organic clothing brand (not a same-name business in another industry).
Sustain by Kat is a slow-fashion, small-batch brand, not fast fashion. It explicitly positions itself around a "slow fashion" future, timeless basics, made-to-order/small-run production in Los Angeles, plant-based natural dyeing done in-house, and biodegradable/compostable garments. Its small scale, LA local manufacturing, and hands-on founder-led dyeing are consistent with slow/small-batch rather than high-volume fast fashion.
Certifications: Sustain by Kat states it uses GOTS (Global Organic Textile Standard) certified organic cotton fabric, thread and labels; this is a certification of the materials/inputs, corroborated by Good On You and the brand's own product pages. There is no evidence the brand itself holds a company-wide GOTS certificate, and no OEKO-TEX, Fair Trade, B Corp, or European Flax certification is claimed or documented. Note: Sustain by Kat publicly critiques GOTS in a blog titled "Where GOTS Falls Short," so it references GOTS at the material level rather than as a brand accreditation..
Sustain by Kat holds the following certifications: Sustain by Kat states it uses GOTS (Global Organic Textile Standard) certified organic cotton fabric, thread and labels; this is a certification of the materials/inputs, corroborated by Good On You and the brand's own product pages. Beyond any paper certification, our scan of 40 Sustain by Kat styles found 100.0% is 100% plant fibre, which is the measurable material fact behind Sustain by Kat's claims.
So many Sustain by Kat basics are pure cotton, but Sustain by Kat's fitted and active styles typically add a small share of synthetic.
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