The label sewn into your activewear contains more information than most people extract from it and less information than most people assume it contains. Knowing how to read it correctly means knowing both what it tells you and what it deliberately or legally does not.
For women building a clean activewear wardrobe, reading labels accurately is the first practical skill. Here is how.
What the fiber composition label tells you
Every garment sold in the United States is legally required to disclose its fiber composition by percentage under the Textile Fiber Products Identification Act. This label lists the fibers present and their relative proportions, from highest to lowest percentage.
A label reading 92% TENCEL Lyocell, 8% Spandex tells you the primary fiber is TENCEL Lyocell, a branded lyocell fiber produced by Lenzing AG, and that the stretch and recovery comes from an 8% spandex component. A label reading 88% Nylon, 12% Spandex tells you the garment is predominantly nylon with a spandex stretch component.
The fiber composition tells you the base materials. It does not tell you the chemical treatments applied to those materials during manufacturing, the production process used to make the fibers, the sourcing of the raw materials, or the labor practices in the manufacturing facility.
Generic fiber names versus branded fiber names
Generic fiber names, cotton, nylon, polyester, spandex, lyocell, modal, tell you the fiber category but not the producer or production standards. Any manufacturer meeting the relevant fiber specifications can use these terms.
Branded fiber names, TENCEL Lyocell, TENCEL Modal, Lycra, ECONYL, provide additional traceability. TENCEL Lyocell specifically indicates the fiber was produced by Lenzing AG under its documented closed-loop manufacturing process, which recovers more than 99% of its production solvent per cycle according to Lenzing's published sustainability data. A label that says lyocell without the TENCEL brand name tells you the fiber type but not who made it or how.
When you see a brand name rather than a generic category on a fiber label, it is worth knowing what that brand represents before assuming it carries specific credentials.
What the care label tells you
The care label uses standardized symbols and text instructions required by the Federal Trade Commission's Care Labeling Rule. It specifies maximum washing temperature, drying method, ironing temperature if applicable, and whether dry cleaning is permitted.
For TENCEL Lyocell activewear, correct care specifications are cold water washing and air drying. A care label that permits hot machine drying on a TENCEL Lyocell and spandex blend is either incorrect or indicates a fiber composition more tolerant of heat than natural fiber blends typically are.
The care label tells you what the manufacturer recommends to maintain the garment. It does not tell you what the garment is made of beyond the fiber label, or what chemical treatments have been applied.
What certifications on tags and hangtags tell you
Certifications appear on hangtags, product pages, and sometimes sewn labels. They are the most informative additional signal beyond the fiber composition and care labels.
OEKO-TEX Standard 100 indicates the finished fabric has been tested by an accredited laboratory for more than 100 harmful substances. This covers both the base fiber and any treatments applied during manufacturing. The certification is verifiable at oeko-tex.com using the certificate number printed on the certification mark. For a full explanation of what OEKO-TEX Standard 100 tests for, how fiber-level and finished-product certification differ, and how to verify a certificate is genuine, the dedicated page on OEKO-TEX and activewear explains it directly.
GOTS (Global Organic Textile Standard) applies to organic fiber products and covers the full supply chain from raw material through manufacturing. It is stricter than OEKO-TEX on sourcing but applies only to certified organic fiber products.
Bluesign certification applies to the fabric production process, covering chemical safety at the mill level. It does not cover the full garment manufacturing chain but provides meaningful assurance about the fabric itself.
FSC (Forest Stewardship Council) certification on a fiber like TENCEL Lyocell indicates the raw material, eucalyptus wood pulp in TENCEL's case, was sourced from forests meeting FSC management standards for biodiversity, worker rights, and long-term forest health.
What the label does not tell you
Chemical treatments applied during manufacturing are not required to appear on US garment labels. PFAS-based water repellency treatments, antimicrobial chemical finishes, formaldehyde-based wrinkle resistance, optical brighteners, and softening agents can all be present in a finished garment without appearing on any label.
Research from the nonprofit MADE SAFE (2022) documented PFAS in products from multiple major activewear brands, none of which disclosed this on product labels. The US EPA classifies certain PFAS compounds as probable human carcinogens.
Country of manufacture is required on US garment labels, but it tells you where the garment was assembled rather than where the fiber was produced or what standards governed the manufacturing process.
Reading the full picture
A complete label reading for any activewear garment covers four things: fiber composition, including whether branded or generic fiber names are used; care instructions, as a signal of fiber type and garment design intent; certifications present on the tag or product page; and what the brand can answer when asked directly about chemical treatments not disclosed on the label.
Bellissima's Sempre Leggings label reads 92% TENCEL Lyocell, 8% Spandex. The TENCEL Lyocell is Lenzing AG's branded fiber with documented closed-loop production credentials. The spandex provides stretch and recovery. The care label specifies cold wash, air dry. No PFAS treatments, antimicrobial chemical finishes, or formaldehyde-based treatments are used in the fabric. Those last facts are not on the label. They are the answer to the question the label does not ask.
The skill worth having
Reading activewear labels well means using the fiber composition and care label as starting points, seeking independent certification as a shortcut to what the label does not disclose, and knowing which questions to ask brands directly. The label is a beginning, not an ending. For a complete non-toxic evaluation framework, the non-toxic activewear buying guide covers the full set of criteria. For help assessing whether your current wardrobe passes, how to tell if your activewear is toxic works through the process step by step. The fabrics to avoid in activewear is a useful companion. And for context on the spandex component specifically, how much spandex is OK in activewear covers what the research says.
Sources
Lenzing AG. (2023). TENCEL Lyocell fiber sustainability and production data. Lenzing Sustainability Report.
OEKO-TEX Association. (2023). OEKO-TEX Standard 100 testing criteria and public verification database. OEKO-TEX Technical Bulletin.
MADE SAFE. (2022). PFAS in activewear: Brand scorecard. MADE SAFE Report.
US Environmental Protection Agency. (2023). PFAS explained. EPA Technical Overview.
Textile Fiber Products Identification Act. (1960). US Federal Labeling Requirements for Textile Products.
US Federal Trade Commission. (2014). Threading your way through the labeling requirements under the Textile and Wool Acts. FTC Business Guidance.
US Federal Trade Commission. (2012). Care Labeling Rule. 16 CFR Part 423.
