How to Read a Fabric Composition Label: A Buyer's Guide for Activewear Brands

Every garment sold in major markets carries a fabric composition label — a small piece of fabric sewn into the side seam that legally declares what the garment is made of. For brand founders and sourcing professionals, reading these labels is not just a consumer skill. It is a critical business competency that affects compliance, quality assurance, and supplier accountability.

This guide explains exactly how to read a fabric composition label, what each element means, how to verify accuracy, and what labeling requirements apply in different markets. By the end, you will be able to spot labeling errors before they become chargebacks or compliance violations.

Why Fabric Composition Labels Matter for Your Brand

Fabric labels serve three critical purposes: legal compliance — the FTC in the US and EU Textile Regulations require accurate fiber content labeling; consumer protection — buyers rely on labels for care instructions and allergen information; and quality assurance — the label is your contractual promise about what the garment contains.

Inaccurate labeling carries serious consequences. The US Federal Trade Commission can fine companies up to $43,792 per violation for false fiber content claims. European authorities can demand product recalls and impose market-access restrictions. For brands selling through retail channels, major retailers may issue chargebacks of 5–15% of the invoice value for labeling non-compliance.

Reading the Fiber Content Line: The Most Important Element

The fiber content line lists all fibers in descending order by percentage weight. For example, "78% Nylon, 22% Spandex" means the fabric is predominantly nylon with spandex providing stretch. Key rules to understand:

• Fibers must be listed by their generic names — "nylon" not "Supplex," "polyester" not "Coolmax"
• Percentages must total 100% — any discrepancy indicates a labeling error
• Fibers under 5% may be grouped as "Other fibers" in most jurisdictions
• The spandex/elastane percentage is critical for activewear — a variation of more than +/-3% from spec will affect stretch and recovery performance
• The first fiber listed determines the garment's fundamental character: nylon for softness, polyester for moisture-wicking

Common Activewear Fiber Compositions: A Quick Reference

Knowing standard activewear blends helps you quickly verify whether a label is reasonable:

• Yoga leggings: 78/22 or 80/20 nylon/spandex — the industry standard for premium performance
• Sports bras: 75/25 nylon/spandex — higher spandex provides compression for high-impact support
• Running tights: 80/20 polyester/spandex — polyester wicks moisture better for sweaty activities
• Training tops: 90/10 polyester/spandex — lightweight with minimal stretch
• Seamless activewear: 80/20 or 70/30 nylon/spandex — higher spandex for compression fit
• Studio hoodies: 80/20 organic cotton/polyester with 5% spandex — comfort with slight stretch

Memorize these ratios. If a label claims 95% Nylon, 5% Spandex for leggings, the elastane content is too low for proper recovery — the garment will likely sag after a few wears.

Decoding Care Label Symbols

Care labels use standardized symbols regulated by ISO and GINETEX. The five basic symbol categories are: wash tub (washing), triangle (bleaching), square with circle (drying), iron (ironing), and circle (dry cleaning). A cross through any symbol means "do not."

Numbers inside the wash tub indicate maximum temperature in degrees Celsius — typically 30°C or 40°C for activewear. Dots on the iron symbol indicate temperature settings: one dot (low, 110°C), two dots (medium, 150°C), three dots (high, 200°C).

For activewear, the most common care symbols are: machine wash cold (30°C), do not bleach, do not tumble dry (or tumble dry low), and do not iron (or iron low). Heat degrades elastane — tumble drying can reduce spandex recovery by up to 30% over 15–20 cycles.

Country of Origin Labeling Requirements

Country of origin must be stated on every garment label in virtually every market. For activewear manufactured in China, the label must say "Made in China." The origin is determined by where the fabric was substantially transformed — typically where it was cut and sewn, not where the fiber was grown or spun.

Different markets have specific rules: the US requires "Made in [country]" or "Assembled in [country]" if only assembly occurs there. The EU requires "Made in [country]" or "Made in EU." If your garment is cut and sewn in China from Korean fabric, the origin is still China. Mislabeling origin can trigger customs holds, seizure, and fines.

RN Numbers and Company Identification

In the United States, an RN (Registered Identification Number) is issued by the FTC and identifies the business responsible for marketing the garment. The RN number does not indicate the manufacturer — it identifies the brand, importer, or distributor who is legally responsible for compliance.

Canada uses a CA number system. The EU does not use RN numbers but requires the importer's name and address. If you are importing activewear to the US from a foreign factory, you need your own RN number from the FTC — registration is free and takes approximately two weeks. Your factory should use its own RN number or yours depending on who is legally responsible.

How to Verify Label Accuracy: Testing Methods

Never trust a label blindly. Here are three verification methods, from quick to definitive:

• Burn test: Burn a small fabric sample. Nylon melts and smells like plastic; polyester melts with black smoke; cotton burns with paper-like ash; spandex leaves a sticky black residue. This takes 30 seconds and catches mislabeled blends immediately.
• Water absorption test: Drop water on the fabric. True moisture-wicking fabric absorbs the droplet within seconds. If water beads up, the fabric has a durable water repellent finish. Slow absorption suggests higher cotton content than labeled.
• Third-party lab testing: Chemical dissolution testing (AATCC 20A) provides exact percentages and is the gold standard. SGS, Intertek, and Bureau Veritas offer fiber composition analysis for $30–100 per test. Test at least one garment per style per color in your first production run.

Common Labeling Mistakes and How to Prevent Them

The most frequent labeling errors in activewear sourcing include:

1. Incorrect fiber percentages — Fabrics stretch during cutting and sewing, which can alter the spandex percentage from the nominal spec. Request test reports to confirm.
2. Wrong fiber names — Using trade names like "Supplex" or "Coolmax" instead of generic names like "nylon" or "polyester" is a common compliance violation.
3. Missing country of origin — Common with products assembled across multiple countries. Determine origin based on substantial transformation.
4. Inconsistent care symbols — Recommending hot water wash for a garment containing 22% spandex will cause premature degradation. Ensure care symbols match fiber content.
5. Wrong fiber order — Fibers must be listed in descending order by percentage. Even if the percentages are correct, wrong order is a legal violation.

Labeling Requirements by Target Market

Different markets have different requirements. If you sell in multiple regions, you need compliant labels for each:

• United States: Fiber content (generic names, descending order), country of origin, RN number or company name, care instructions per ASTM D5489. English only.
• European Union: Fiber content (generic names, descending order), country of origin if non-EU, importer name and address, care symbols per ISO 3758. Labels in local language(s).
• United Kingdom: Post-Brexit, UK follows largely aligned rules with UKCA labeling. English language.
• Canada: Fiber content, country of origin, CA number, bilingual labeling — English and French required on the same label.
• China: GB/T 29862-2013 requires fiber content, safety category (A/B/C), and manufacturer info in Chinese.
• Australia: Fiber content, country of origin (mandatory "Made in..." label), care instructions per AS/NZS 1957.

Building a Label Verification Process for Your Brand

Create a standard operating procedure for label verification across every production run:

1. Before production: Send label specifications to your factory with exact wording, font size, placement, and material requirements. Include a visual mock-up.
2. During sampling: Request photos of labels sewn into pre-production samples. Verify all text, symbols, and placement against your specifications.
3. Before shipment: Have your QC inspector photograph labels from five randomly selected units per style per color. Cross-check fiber content against the actual BOM and fabric purchase orders.
4. Archive: Save all label photos with your QC documentation for each production run. These records are your evidence if a compliance dispute arises.

This process takes approximately 15 minutes per production run but prevents chargebacks and regulatory fines that can cost thousands.

Frequently Asked Questions About Fabric Labels

What does "80% Nylon, 20% Elastane" mean for performance?

This is the premium activewear standard. Nylon provides softness, strength, and shape retention; elastane delivers stretch and recovery. Expect a smooth, opaque fit with excellent durability across hundreds of wears.

Is recycled polyester as good as virgin polyester?

Yes. rPET offers identical moisture-wicking, drying speed, and durability to virgin polyester. Look for GRS certification to verify the recycled content claim.

Can I trust a fabric label without third-party testing?

No. Fabric label errors are common, especially on first production runs. Always test at least one garment per style per color with a lab like SGS or Intertek.

What is the best fabric blend for yoga leggings?

75–80% Nylon blended with 20–25% Elastane. This combination offers the buttery-soft hand feel, four-way stretch, and reliable recovery that yoga practitioners expect.

Final Thoughts: Labels Are Your First Quality Check

The fabric composition label is not a legal formality — it is your first and most accessible quality checkpoint. Every time you pick up a sample from your supplier, the label tells you whether the fabric matches your specifications, whether the certifications are legitimate, and whether the garment will deliver the performance your customers expect.

Ready to source activewear with confidence? Contact Bloomto's team for expert guidance on fabric selection and composition verification for your next collection.