OEKO-TEX Standard 100 tests a finished textile, and every component in it, for a long list of harmful substances. GOTS (the Global Organic Textile Standard) certifies that the fiber is organic and that every company processing and trading it meets environmental and social rules. Put simply: OEKO-TEX tells you what is not in the fabric, and GOTS tells you where the fiber came from and how it was handled on its way to you.
They answer different questions, which is why a brand can hold one, both, or neither. Below: what each one checks, what the fine print means for silk, and how to look up any brand's certificate yourself in about two minutes. Including ours.
Why I read certificates before I read reviews
I was diagnosed with CLL at 44. After treatment I developed MCAS (mast cell activation syndrome), and my body started reacting to things it used to ignore. I needed to know exactly what was touching my skin, and when I went looking for silk, almost nobody showed me a certificate I could check. So I built Wink Silk around silk with certificate numbers you can type into a public database. If you are managing MCAS, allergies or treatment, a certificate is information, not a medical answer, so bring it to your care team. (They love homework. Mostly.)
What OEKO-TEX Standard 100 certifies
OEKO-TEX is an association of independent textile testing institutes. Its best-known label, Standard 100, means a product was lab tested against a list of substances that can be harmful to health, including certain dyes, formaldehyde, heavy metals and pesticide residues. The list is reviewed and updated regularly, and certificates have to be renewed.
Two details matter more than the logo:
- It covers every component. Thread, zipper, label, lining. A silk pillowcase sewn with an untested zipper does not pass.
- It uses product classes. The more skin contact, the stricter the limits. Class I covers articles for babies and toddlers up to age three and is the strictest. Class II covers products with a large area of skin contact, like bedding and clothing. Class III covers products with little or no skin contact, and Class IV covers decoration materials such as curtains.
What Standard 100 does not tell you: whether the fiber is organic, how the factory treats its workers, or what happens to its wastewater. It is a test of the finished product, not the process behind it.
OEKO-TEX Made in Green
Made in Green goes further. A Made in Green product has passed the same harmful substance testing and was also made in facilities certified for environmentally friendly production and socially responsible working conditions (OEKO-TEX calls that facility certification STeP). Every Made in Green label carries a product ID and QR code, so you can trace the production stages behind that specific item.
What GOTS certifies
GOTS starts with the fiber. The raw fiber has to come from certified organic production, and GOTS then sets rules for every step after that: processing, dyeing, finishing, manufacturing and trading. Those rules cover restricted chemical inputs, wastewater treatment and social criteria based on core labor standards.
There are two label grades:
- "Organic": at least 95% certified organic fiber.
- "Made with organic": at least 70% certified organic fiber.
The part most shoppers miss is that GOTS certifies companies, stage by stage. Each company in the chain that processes or trades the goods needs its own certification for the finished product to carry the GOTS label. One uncertified link and the chain is broken.
For silk, "organic" means organic sericulture: the mulberry trees the silkworms eat from are grown without synthetic pesticides or fertilizers, and the silk is processed under GOTS rules. It is not a different kind of silk. I break that down in mulberry silk vs regular silk.
GOTS vs OEKO-TEX side by side
| OEKO-TEX Standard 100 | OEKO-TEX Made in Green | GOTS | |
|---|---|---|---|
| Main question | Is the finished product tested for harmful substances? | Tested, and made in certified sustainable facilities? | Is the fiber organic, and was every stage responsibly run? |
| What gets checked | The product and all its components, in a lab | The product plus the production facilities | Fiber origin, chemical inputs, wastewater, labor, traceability |
| Organic fiber required? | No | No | Yes: 95% for "organic", 70% for "made with organic" |
| Strictness tiers | Product classes I to IV (Class I strictest) | Built on Standard 100 testing | Two label grades |
| Who holds it | The company whose product was tested | The company, with traceable facilities | Each company in the supply chain |
| Where to verify | Label Check at oeko-tex.com | Product ID or QR code at oeko-tex.com | Public database at global-standard.org |
How to verify any certificate, including ours
Checking OEKO-TEX
Go to oeko-tex.com and open Label Check. Type in the certificate number exactly as the brand prints it (for example, BJ025 172302). Then look at four things: is the certificate valid today, whose name is on it, which articles it covers, and which product class applies. For Made in Green, enter the product ID or scan the QR code on the label.
Checking GOTS
Go to global-standard.org and open the public database of certified suppliers. Search by company name or license number. Check that the certificate is current and that the scope lists the product you are buying (pillowcases, not only yarn or fabric). The certification body, such as Control Union, is named there too.
The question almost nobody asks
Whose name is on the certificate? Often it is the manufacturer, not the brand on the box. That can be completely legitimate. You just deserve to know which one it is.
Where Wink Silk stands, plainly
Our silk is certified by our manufacturer, Zibo Daranfang: OEKO-TEX Standard 100 certificate BJ025 172302 (tested by TESTEX), which covers pillowcases, eye masks and scrunchies, and GOTS license GOTS-16032, which covers pillowcases. When you look those numbers up, the holder is our manufacturer, not Wink Silk. I would rather you hear that from me than discover it yourself. Wink Silk is pursuing its own GOTS Trader and OEKO-TEX certifications, and every number lives on our certifications page so you can check it tonight.
What to look for on any brand's page
Before you buy from anyone, including us, look for three things on the product page.
- A certificate number, not just a logo. A logo is a claim. A number is something you can check.
- The name of the certificate holder. It may be the brand or its manufacturer. Both can be legitimate. You deserve to know which.
- A scope that matches the product. A certificate that covers yarn or fabric is not the same as one that covers finished pillowcases.
If a brand makes no certification claim at all, that does not prove anything is wrong with the silk. It means there is nothing for you to check.
Which one should you look for?
Look for OEKO-TEX Standard 100 if your main concern is what touches your skin for eight hours a night. It is the certification that tests the finished product. For bedding, Class II or Class I is what you want to see. My guide to silk pillowcases for sensitive skin goes deeper.
Look for GOTS or Made in Green if farming practices, wastewater and working conditions matter to you as much as the fabric itself. If you are specifically shopping GOTS silk, I cover it in what GOTS certification means for a silk pillowcase.
Who a certificate is not enough for: anyone who assumes it measures quality. Neither label tells you momme, grade, weave or whether the silk is real. A certified 16 momme pillowcase is still a 16 momme pillowcase. Pair the certificate with the checklist in what to look for in a high quality silk pillowcase.
If you want the Performance Luxury Silk™ version, our Douceur Doublure™ is two layers of 25 momme, Grade 6A mulberry charmeuse, with a hidden zipper and a certificate number you can look up before you ever open the box. There are 330 hand-numbered pieces, and they will not be restocked. We all deserve to know exactly what we are sleeping on.
Silk with certificate numbers you can check tonight. 330 numbered pieces, never restocked.
Frequently Asked Questions
Is OEKO-TEX better than GOTS?
Neither is better, because they measure different things. OEKO-TEX Standard 100 lab tests the finished product and its components for harmful substances. GOTS certifies that the fiber is organic and that each company processing and trading it meets environmental and social criteria. If skin contact is your main concern, OEKO-TEX speaks to it directly. If farming and working conditions matter most, GOTS covers more of the chain. Many shoppers look for both.
What does GOTS certification mean for silk?
For silk, GOTS means the silk comes from certified organic sericulture, where the mulberry trees the silkworms feed on are grown without synthetic pesticides or fertilizers, and that every company that processes and trades it is certified. A product labeled organic must contain at least 95% certified organic fiber, and made with organic at least 70%. It does not mean a different species of silk.
Are there certifications besides GOTS?
Yes. OEKO-TEX Standard 100 is the most common certification on silk pillowcases and tests finished products for harmful substances. OEKO-TEX Made in Green adds traceable production in facilities certified for environmental and social standards. Each answers a different question than GOTS does. Whatever a brand claims, look up the number: Label Check at oeko-tex.com, or the public database at global-standard.org.
How do I check if an OEKO-TEX certificate is real?
Go to oeko-tex.com, open Label Check, and enter the certificate number exactly as printed. A real certificate shows as valid and lists the certificate holder, the articles covered and the product class. If the number returns nothing, the certificate has expired, or the holder is a company you have never heard of, ask the brand to explain. The holder is often the manufacturer rather than the brand.
What is OEKO-TEX Class 1 vs Class 2?
OEKO-TEX Standard 100 sorts products into four classes by how much they touch skin. Class I covers articles for babies and toddlers up to three and has the strictest limits. Class II covers products with a large area of skin contact, such as bedding and clothing. Class III covers items with little or no skin contact, and Class IV covers decoration materials. For a pillowcase, Class I or II is what you want.
Does Wink Silk hold its own GOTS certificate?
Not yet, and I want to be clear about that. Our silk is certified by our manufacturer, Zibo Daranfang, under GOTS license GOTS-16032, which covers pillowcases, and OEKO-TEX Standard 100 certificate BJ025 172302, which covers pillowcases, eye masks and scrunchies. Wink Silk is pursuing its own GOTS Trader and OEKO-TEX certifications. Every number is listed on our certifications page so you can look it up yourself.
