Spec decoded

OEKO-TEX, GOTS and RDS decoded

Updated August 2026

Three logos cover almost every legitimate bedding claim, and each one certifies something narrower than shoppers assume. Here is exactly what each tests, where the thresholds sit, and which are worth making a hard requirement.

1. OEKO-TEX Standard 100

Standard 100 tests the finished textile for harmful substances — formaldehyde, azo dyes that release restricted amines, heavy metals, pesticide residue, phthalates, chlorinated phenols and several hundred more. If a product carries the label with a valid certificate number, every component was tested: fabric, thread, buttons, zipper tape, even the printed label.

What it does not cover: organic farming, fiber quality, thread count honesty, durability, labor conditions, or environmental impact of the mill. An OEKO-TEX certified microfiber cover is chemically clean and still microfiber. Treat it as a floor, not a ceiling — it is the one certification worth requiring on anything that touches your skin for eight hours a night.

Testing is banded by how much skin contact a product has. Product Class I is articles for babies and toddlers and carries the strictest limits; Class II covers items worn or slept against the skin, which is where duvet covers, sheets and comforters land; Class III is for products without direct skin contact; Class IV is decorative material like upholstery. Certificates expire after twelve months and must be renewed, so a number is checkable and a logo alone is not.

2. GOTS — the Global Organic Textile Standard

GOTS is the stricter and rarer label. To carry the full "organic" grade a product must contain at least 95% certified organic fiber, with the remaining 5% restricted and never conventional cotton. A second grade, "made with organic," requires at least 70%. On top of the fiber percentage, GOTS governs the whole processing chain: which dyes and auxiliaries are permitted, wastewater treatment at every mill, and social criteria covering wages, hours and freedom of association.

That combination is why GOTS costs more and why so few Amazon-tier products carry it. It is also the only common label that tells you anything about how the cotton was grown — the practical differences are in organic cotton bedding. Note the direction of the relationship: GOTS certified goods are also tested for harmful substances, so GOTS effectively includes what OEKO-TEX guarantees, but not the reverse.

3. RDS and down claims

The Responsible Down Standard certifies animal welfare and traceability through the supply chain: no live plucking, no force feeding, and a chain of custody from farm to finished comforter. It says nothing about fill power, cleanliness, or how warm the comforter will be. A 550 fill power RDS comforter and an 800 fill power RDS comforter carry the identical logo.

The cleanliness spec you actually want alongside it is oxygen number and turbidity, which measure residual organic matter in washed down. Those are what determine whether a comforter smells when it gets damp and whether sensitive sleepers react to it. Global Traceable Down (TDS) is a stricter parent-farm variant of RDS. If you are still deciding whether down is the right fill at all, down vs. down alternative compares them directly.

4. Worked example: what the thresholds actually permit

Certification limits are numbers, and numbers can be applied to the object on your bed.

Formaldehyde. OEKO-TEX sets a limit of 75 mg per kilogram of textile for Class II, the band bedding falls into. A queen duvet cover weighs roughly 1.4 kg. At the limit:

1.4 kg × 75 mg/kg = 105 mg of formaldehyde in a fully certified cover. For a Class I baby item the limit is 16 mg/kg, so the same 1.4 kg of fabric would be capped at 1.4 × 16 = 22 mg — roughly a fifth as much. Certification is a ceiling, not an absence, and the ceiling moves depending on the class a product was tested under. That is why the certificate number matters more than the logo: it names the class.

Organic content. Say a duvet cover is labeled organic and its fiber content reads 70% organic cotton, 30% polyester. On a 1.4 kg cover that is 0.7 × 1,400 = 980 g of organic cotton and 420 g of polyester. Against the GOTS thresholds:

The cover can legally say "made with organic cotton" while 420 grams of it is petroleum-based fiber. The phrasing on the label is doing precise work, and the missing five characters between "organic" and "made with organic" are worth 25 percentage points of content.

5. Labels that mean less than they sound

• "Eco-friendly," "green," "natural," "chemical-free." Unregulated in most markets. No test, no auditor, no threshold.
• "Hypoallergenic." A marketing term with no standardized test behind it for textiles.
• "Made with OEKO-TEX certified fabric." The fabric was certified; the finished product was not, so dyes, prints and hardware added afterward are untested.
• "Organic bamboo." Bamboo viscose is chemically dissolved and regenerated, which destroys the organic chain of custody — the process is described in bamboo duvet covers. Closed-loop lyocell has a better environmental case, covered in TENCEL bedding.
• A logo with no certificate number. Both OEKO-TEX and GOTS issue verifiable numbers you can look up in the issuing body's public database.

Red flags

• Certification claimed in the product title but absent from the specification table.
• A GOTS claim with a fiber content under 70%. Arithmetically impossible.
• "OEKO-TEX Class I" on an adult comforter. Possible but unusual, and often just copied text.
• RDS cited as evidence of warmth or quality. Different subject entirely.
• An expired certificate number. They lapse annually.

Where to go next

Certifications are one check among several — the full sequences are in the duvet cover buying guide and the comforter buying guide, with fiber-level detail in the materials hub. Shortlists where certification was part of the screen: best duvet covers · cotton · down comforters. Everything else in all guides.