OEKO-TEX STANDARD 100 means a sample of a textile was tested against limits for substances that are restricted in law — and passed. It says nothing about organic farming, carbon, or working conditions. This guide covers what is actually measured, what the four product classes mean, what changed on 1 June 2026, and how to pull any certificate’s status and full scope straight from the issuing body.
OEKO-TEX gives every certificate a permanent web address. Paste the number from a label or a product page and this builds the link to that certificate’s own record, which returns its status, who holds it, the product class, and the full scope text describing exactly which articles and fibres it covers. The answer comes from OEKO-TEX, not from us.
Nothing is sent anywhere. The number stays in your browser — this only assembles a web address from it.
STANDARD 100 is a laboratory test for harmful substances in a finished textile. A sample goes to an accredited institute and is measured against limit values for restricted substance groups. If it passes, the article type is certified for a defined period and given a number you can look up. Every component is in scope, not just the cloth: threads, buttons, zips, prints and labels are tested too, because that is where several of the restricted substances actually live.
These are the three most cited groups and the legal limits that sit behind them. Each figure is an EU restriction under REACH, not an OEKO-TEX marketing number — OEKO-TEX limits are set at or below the legal thresholds and get stricter as skin contact increases.
Used in easy-care and crease-resistant finishes. The EU limit in textiles is 75 mg/kg. A derogation allowed 300 mg/kg for jackets, coats and upholstery until 1 November 2023; since then the lower limit applies to those too.
REACH Annex XVII, entry 72 — ECHA
Some azo colourants can break down to release aromatic amines from a list of substances of concern. Where those amines are detectable above 30 mg/kg, the dye may not be used in textiles or leather that come into direct and prolonged contact with skin or the mouth.
REACH Annex XVII, entry 43 — the list of amines
The one most guides miss, because it is not about the fabric. Nickel release from parts in direct and prolonged skin contact must not exceed 0.5 µg/cm² per week — and the restriction names rivet buttons, rivets, zips and metal marks used in garments. For posts inserted into pierced holes the limit is 0.2 µg/cm² per week.
REACH Annex XVII, entry 27 — ECHA
OEKO-TEX describes its own testing as covering around 100 test parameters. We use their phrasing rather than converting it into a hard count, because the list changes with each annual update and a precise number would be wrong within a year.
Not every OEKO-TEX certificate means the same thing. The standard has four product classes and the limits get stricter the more the article touches skin. A curtain and a babygrow are both certifiable, to very different thresholds. The class is printed on the certificate record, so it takes one look to see which one you are actually being shown.
Articles for the very young. The strictest limits in the standard, set for skin that is thinner and more permeable and for garments that end up in mouths.
Worn against the body: T-shirts, underwear, bedding. Stricter than classes III and IV, less strict than class I.
Outerwear and linings — things worn over something else. Limits relax accordingly.
Furnishing materials: curtains, tablecloths, upholstery fabrics. Least skin contact, least strict.
The practical use of this. When a brand shows you an OEKO-TEX label, the class tells you how much it is worth for the product in your hand. A class IV certificate on something you wear against your skin is not the reassurance it looks like — and you can only tell by opening the record.
For what it is worth here: the certificate covering our organic cotton tee is class I. It is held by Stanley and Stella S.A., our blank supplier — not by us — and the number is 2012163 if you want to read it yourself. More on that below.
Class definitions from OEKO-TEX’s own description of STANDARD 100.
Most pages about textile chemistry are written to alarm you. This one is written to tell you what is actually established, by whom, and what it does not extend to. Several substances restricted in textiles carry serious classifications — and those classifications almost always come from workplace exposure studies, not from wearing a shirt. Both halves of that sentence are true, and leaving either one out would be misleading.
This is not medical advice. We sell clothes; we are not clinicians. Everything below is a summary of published regulatory and scientific classifications, each linked to its source so you can read the original. If you have a specific health concern — a skin condition, a reaction, a question about an infant — ask a doctor, not a clothing brand.
The International Agency for Research on Cancer classifies formaldehyde in Group 1 — carcinogenic to humans. It was moved to Group 1 in 2004, and Volume 100F reaffirmed it in 2012 on the basis of nasopharyngeal cancer.
Studies of occupational inhalation exposure — people breathing it at work. The evidence was judged sufficient for nasopharyngeal cancer. In the 2012 re-evaluation a small majority of the Working Group also found sufficient evidence for leukaemia, particularly myeloid leukaemia — an upgrade from the 2004 evaluation, which had called that evidence “strong but not sufficient”.
IARC Monographs Volume 100F (2012), which reaffirmed Group 1 — IARC
That is not a finding that formaldehyde residue in clothing causes cancer, and anyone telling you it is has gone past the evidence. At the residue levels found in textiles the recognised issue is skin irritation and allergic contact dermatitis. The EU limit for formaldehyde in textiles is 75 mg/kg.
REACH Annex XVII, entry 72 — ECHA
Certain azo colourants can break down to release aromatic amines from a defined list of substances of concern. The EU maintains that list and restricts the dyes that release them.
Above 30 mg/kg of a listed amine, the dye may not be used in textiles or leather that come into direct and prolonged contact with skin or the oral cavity. That covers clothing, bedding, towels, nappies, footwear and gloves among others.
REACH Annex XVII, entry 43
The restriction is on dyes that release listed amines above the threshold — not on azo dyes as a category. Most azo dyes are not restricted. “Contains azo dyes” on its own tells you nothing.
Nickel release from items in prolonged skin contact is restricted in the EU. The restriction explicitly names rivet buttons, rivets, zips and metal marks used in garments — so it applies to clothing through its fittings, not its cloth.
REACH Annex XVII, entry 27 — ECHA
0.5 µg/cm² per week. “Prolonged” contact is defined too: at least 30 minutes on one or more occasions within two weeks, or at least 10 minutes on three or more occasions within two weeks.
This is the argument for testing components rather than fabric. A certificate whose scope covers only the cloth has not addressed the metal snap sitting against your skin. The good ones list the trims explicitly.
The version of this guide we replaced carried claims we could not trace to a primary source. Rather than soften them, we deleted them. Here is what went and what would be needed to put any of it back.
OEKO-TEX updates its criteria every year. The 2026 revision took effect on 1 June 2026 after a three-month transition, and two of the four changes are about traceability rather than chemistry — they close gaps that let a certificate rest on paperwork from someone a supplier had never directly dealt with.
Previously a company could support its certification with a certificate from a second-tier supplier — its supplier’s supplier. Now that is accepted only for a first-time certification. At renewal, the upstream certificate has to come from the direct, first-tier supplier.
Transition: second-tier certificates still accepted for renewals until June 2027.
Dyeing, washing, printing and finishing are where most restricted substances enter a textile. Uncertified wet processes are now accepted only for initial certification. At renewal, every wet process in the supply chain must itself be certified.
Transition: uncertified wet processes remain acceptable until June 2027.
Risk parameters are substances restricted in EU law and treated as critically significant to a certification. Previously a finding meant supplying an improved sample with a statement explaining the change. From 1 June 2026, the institute also runs a second test series within the certificate’s year of validity.
From 2026 the RSL is published as a separate spreadsheet rather than sitting inside the standard document. OEKO-TEX’s stated reason is easier comparison and clearer visibility of the requirements.
Both changes with a transition period run to June 2027, so during the changeover a valid certificate may have been issued under either the old or the new rules. Source: OEKO-TEX new regulations 2026 and the STANDARD 100 product dossier, dated 3 March 2026.
Real phrasings of the kind brands use. Two of the five are perfectly legitimate, which is the point — the skill is telling a weak claim from a fair one, not assuming everything is a lie. Answers explain the reasoning either way.
1. “Our fabric is OEKO-TEX certified, so it’s organic and chemical-free.”
Doesn’t hold up — two errors in one sentence. STANDARD 100 requires no organic fibre at all; a fully synthetic garment can carry it. And “chemical-free” is not a thing a textile can be. The standard limits specific substances to measured thresholds; it does not remove chemistry from cloth.
2. “Our supplier holds OEKO-TEX STANDARD 100 certificate 12345678. We don’t hold one ourselves.”
Fair — and better than most. Certificates belong to named legal entities, usually mills and garment makers rather than the brand selling to you. Saying so plainly, and giving the number so you can check it, is exactly the honest form. This is the claim we make ourselves.
3. A product page showing the OEKO-TEX label as an image, with no number anywhere.
Doesn’t hold up. Not necessarily false — but unverifiable, which for your purposes is the same thing. Every certificate has a number and a permanent record. A logo with no number is a picture of a certificate. Ask for the number; a legitimate supplier has it to hand.
4. “OEKO-TEX certified — guaranteed safe for sensitive skin and babies.”
Doesn’t hold up, on two counts. “Guaranteed safe” overstates what a substance test can establish. And the class matters: only class I is set for babies. A class III or IV certificate does not carry the limits designed for infant skin, so the sentence claims something the certificate may not support. Check the class in the record.
5. “This certificate covers our T-shirts. It doesn’t cover our tote bags — that supplier’s certificate expired and hasn’t been replaced.”
Fair, and unusually so. Scope is per article type, and a brand naming the products a certificate does not cover is telling you the thing that costs it something to say. That is close to the strongest signal available. It is also, word for word, our own position on our tote bags.
Every one of these is settled in under a minute at OEKO-TEX Label Check or with the lookup at the top of this page. For GOTS claims, the same discipline applies — our GOTS guide covers that register.
Design Delight Studio holds no OEKO-TEX certification, and in fact holds no certifications at all — our suppliers do, and we name which. One OEKO-TEX certificate applies to one of our blanks. It is not ours, we did not pay for it, and we can only point at it. Here it is anyway, with the number, so you can check it against everything this page just told you.
OEKO-TEX STANDARD 100 certificate No. 2012163, issued by Centexbel and held by Stanley and Stella S.A., our blank supplier. Product class I — the strictest class in the standard.
Its scope covers knitted garments including T-shirts made of 100% cotton, and blends with recycled polyester below 20%, including trims, sewing threads, labels, buttons, zips and metal snaps. Our tee is 100% cotton, so it falls inside that scope.
Read the certificate recordWe used to show an OEKO-TEX certificate on our tote bags. It had expired, and no replacement was published by the supplier. We removed the claim from every tote product page rather than leave an expired certificate standing behind it.
There is currently no OEKO-TEX certificate we can point to for our totes. If that changes we will say so.
For a long time our tee carried certificate No. 1112055. It was genuine, current, and issued to our actual supplier — it passed a status check cleanly. It failed on scope: it was gated on articles with recycled content above 20%, and our tee is 100% cotton with none. A real certificate for a fabric we do not use is not evidence about our product.
We replaced it with 2012163, whose scope is the mirror image and does cover the tee, and published the correction with dates. That error is the reason the lookup on this page tells you to read the scope rather than stopping at the status.
This page is a guide to a standard, not a sales page. If you want to check what we actually claim and what backs it:
These cover what the certification means and what it does not, the four product classes, how to verify a certificate, what the standard tests for, how it differs from GOTS, what changed in 2026, and what our own position actually is.
