Oeko-Tex Standard 100 on T-shirts, what is tested
Oct 07, 2026
Short answer: Oeko-Tex Standard 100 is a test of textiles for substances that can be harmful, including in dyes and finishing. The label applies to the tested product and says nothing about fit or durability. So look closely at what was tested when you see it on a T-shirt.
What Oeko-Tex Standard 100 tests
Oeko-Tex Standard 100 is a testing system for textiles. By the criteria of the label, things examined include possible harmful substances and values such as pH and colour fastness. Every part of the garment, from fabric to thread and buttons, can be included in the testing, so the finished product can stand up to it.
Who tests and how it works
The testing takes place at independent institutes, which examine samples of the clothing and judge them against the requirements of the label. If the requirements are met, a certificate is issued for a particular product or group of products. The certificate is therefore tied to something concrete and not to a whole company.
What the testing means for a T-shirt
When you look at bamboo T-shirts for men, Oeko-Tex Standard 100 is an example of documentation about substances in the textile. A T-shirt sits close to the skin for many hours, so it is natural to ask what has been tested. That is a question you can ask of any clothing.
What the label does not say
The label says nothing about how the T-shirt fits, how well it handles washing or how long it lasts. It also says nothing about how the fibres were grown. These are other qualities that you have to judge from fit, fabric and care, and not from a single label.
Dyes, pH and colour fastness
Two of the things that can be part of the testing are pH and colour fastness. Colour fastness is about whether the colour stays in the fabric when you wash it or when it gets wet with sweat. You can also check that yourself at home at the first wash, by watching whether the water takes on colour.
How to find the label on clothing
The label may appear on a tag in the garment, on the packaging or on the product page. Look for the name and a certificate number. If there is only a logo without a number, it is harder to check. Make a note of what you saw if you are comparing several T-shirts.
How to look up the number
Some labels let you look up a certificate number on their own website. Then you can see whether it applies to exactly the T-shirt in your hand or to another product. It is a simple check that takes a few minutes and makes you less dependent on taking a logo at face value.
What else to look at
The label is one piece. Also look at the fit in the shoulders and the length, the weight of the fabric and the care instructions. Clothes that fit well and are washed properly last longer than clothes that only have impressive documentation. That goes for socks for men and bamboo boxer briefs too.
Frequently asked questions
Does Oeko-Tex Standard 100 mean the clothing is organic?
No. The label is about testing substances in the textile, not about how the fibres were grown. Those are two different questions that belong to different labels.
Does the label apply to all products from a brand?
No, the certificate is tied to particular products or product groups. Look up the certificate number if you want to know whether it applies to the exact T-shirt you are considering.
Can I be sure a T-shirt is free of everything harmful?
A label is documentation by certain criteria, not a promise about everything. If you have sensitive skin or allergies, talk to your doctor and try new clothes carefully.
