No, most sewing thread is not biodegradable because it is made from synthetic materials like polyester or nylon. However, cotton and silk threads are biodegradable as they are natural fibers. Biodegradability depends on the thread’s material composition and exposure to the right environmental conditions.
In this article, we’ll explore what makes thread biodegradable, examine different thread types and their environmental impact, and help you choose sustainable alternatives for your sewing projects.
What makes a thread biodegradable?
The biodegradability of sewing thread primarily depends on its material composition. Understanding what makes thread biodegradable requires examining both the fiber type and the breakdown process.
Natural vs synthetic fibers
Natural fibers and synthetic fibers differ fundamentally in their environmental impact. Natural fibers—derived from plants and animals—are inherently biodegradable and renewable, whereas synthetic fibers typically are not. Cotton, silk, wool, hemp, jute, and linen come from naturally occurring sources, reducing the need for petroleum-based chemicals.
Hemp stands out as particularly eco-friendly, biodegrading in just weeks, while cotton takes approximately five months. Wool, a protein-based fiber, takes longer but still breaks down completely within 6 to 12 months while releasing valuable nutrients back into the soil.
Synthetic fibers present a stark contrast. Materials like polyester, nylon, and acrylic are manufactured from fossil fuels and can persist in the environment for centuries. Polyester, the most common thread type, takes between 20 to 200 years to decompose. Spandex and elastane may take up to 200 years, and nylon essentially never biodegrades naturally.
How biodegradation works in textiles
Biodegradation occurs through a two-stage process. First, extracellular enzymes and environmental factors like oxidation and hydrolysis break down long polymer chains into shorter fragments called oligomers. Second, microorganisms (primarily bacteria and fungi) consume these fragments through biomineralization, converting them into simpler compounds.
The process can occur in two ways:
- Aerobic degradation: Happens with oxygen present, producing CO₂, water, and biomass
- Anaerobic degradation: Occurs without oxygen, producing CO₂, water, methane, and biomass
Several factors influence biodegradation speed:
- Temperature and moisture levels
- Oxygen availability
- Presence of suitable microorganisms
- Chemical treatments applied to textiles
- Polymer structure and molecular weight
For natural fibers, microorganisms target specific bonds within the polymer structure, breaking them into simpler molecules they can consume as food. This process is significantly more challenging for synthetic polymers, which are designed to resist degradation.
Essentially, biodegradable threads must be capable of breaking down rapidly through biological action. According to the European Commission, an item is considered biodegradable “if it reaches 90% of its biodegradation within 6 months once put in the right conditions”.
Is sewing thread biodegradable?
The answer to whether sewing thread is biodegradable depends entirely on what it’s made from. Different thread materials break down at varying rates, with some never fully decomposing at all.
Polyester thread and its environmental impact
Polyester, the most common sewing thread, creates significant environmental concerns. First and foremost, it’s derived from petrochemicals, making it fundamentally non-biodegradable. When discarded, polyester thread can take over 200 years to break down in landfills. During this time, toxic materials from production leach into soil and potentially contaminate local water supplies. Additionally, polyester thread contributes to microplastic pollution as it sheds tiny fibers during washing and wear. These microfibers disrupt aquatic ecosystems when fish ingest them, consequently affecting humans who consume the fish.
Cotton thread: biodegradable but with caveats
Cotton thread offers a more environmentally friendly alternative as a natural, cellulose-based fiber. Microorganisms recognize cotton’s long chain glucose molecules as food sources, enabling biodegradation. Furthermore, cotton biodegrades in all natural environments including soil, wastewater, freshwater, and saltwater conditions. Nevertheless, cotton’s biodegradability has limitations. The fiber’s outer cuticle layer can resist water penetration, thereby slowing the breakdown process. Moreover, while cotton contains 90-95% biodegradable cellulose, it’s not 100% biodegradable.
Silk, linen, and jute threads
Natural fibers like silk, linen, and jute provide excellent biodegradable alternatives. Linen, made from flax fiber, can decompose remarkably quickly—in just two weeks under ideal conditions. In contrast, jute, derived from the bark of white jute plants, is often called the “golden fiber” and is 100% biodegradable. Regardless of its ecological benefits, jute maintains impressive strength, exhibiting high tenacity that withstands considerable pressure.
New biodegradable innovations like lyocell
The thread industry is developing innovative solutions to address environmental concerns. Coats’ EcoRegen represents a breakthrough as a 100% lyocell thread made from sustainably sourced wood pulp. This thread is fully biodegradable and compostable due to its cellulosic origin. As opposed to cotton, lyocell requires no irrigation, pesticides, or labor-intensive cultivation. Other advancements include EcoCycle, a water-dissolvable thread facilitating garment recycling, and Eco-B, a recycled polyester thread with additives that reduce synthetic fiber accumulation in landfills.
Eco-friendly alternatives to polyester thread
For those seeking biodegradable sewing options, the market now offers several sustainable thread alternatives that reduce environmental impact while maintaining quality.
Organic cotton threads
Organic cotton threads provide an excellent eco-friendly alternative to synthetic options. Made without chemical pesticides, these threads are fully biodegradable and recyclable. Organic threads certified by GOTS (Global Organic Textile Standard) ensure sustainable and ethical textile production that’s worker-friendly and better for the planet. Primarily, the strength of organic cotton threads increases when wet, making them durable for various applications. One notable example is TEX 40 natural thread dyed with vegetable dyes, which is sturdier than other multi-purpose threads and ideal for sportswear and home decor items.
Silk and linen threads
Silk and linen threads offer natural biodegradability alongside impressive performance characteristics. Linen thread, made from the finest Egyptian flax, is stronger than cotton, more resistant to sunlight, and dries faster. Furthermore, linen thread doesn’t stretch yet knots exceptionally well. Likewise, silk threads provide softness and durability as an all-natural material. Both options work excellently in projects requiring strength without environmental compromise.
Lyocell and EcoRegen threads
Coats EcoRegen represents a major advancement in biodegradable threads. This 100% lyocell thread is made from sustainably sourced wood pulp and is fully biodegradable and compostable. Unlike cotton, lyocell requires no irrigation, pesticides, or labor-intensive processes during cultivation. Correspondingly, it offers superior elongation and comfort while maintaining the highest dry and wet strength among cellulosic fibers. Birla Cellulose, which supplies the raw material, plants approximately three times the trees they harvest, creating a carbon-neutral production cycle.
Recycled polyester with additives
Although polyester isn’t naturally biodegradable, innovations have created more sustainable options. Coats Eco-B combines recycled polyester with an additive from CiCLO that creates biodegradable “spots” in the polymer matrix. These spots allow naturally-occurring microbes to break down plastics similar to natural fibers. Additionally, companies like A&E Gütermann offer 100% recycled polyester threads (Mara rPET) with quality and tear resistance comparable to non-recycled threads.
How to choose sustainable sewing thread
Selecting eco-friendly thread requires knowledge about certifications, environmental impact, and intended use. First and foremost, I recommend looking beyond marketing claims to verify a thread’s sustainability credentials.
Check for certifications (GRS, GOTS, etc.)
When shopping for sustainable sewing thread, certifications provide assurance about environmental claims. The Global Organic Textile Standard (GOTS) certifies that cotton threads are made from 100% organically grown fibers without chemical pesticides. This certification ensures sustainable and ethical textile production practices that are worker-friendly and environmentally responsible.
For recycled materials, look for the Global Recycled Standard (GRS) certification. This verifies that threads contain recycled materials and meet strict environmental, social, and chemical standards throughout the supply chain. Many manufacturers, including AMANN, offer GRS-certified recycled polyester threads that maintain nearly identical quality characteristics as their standard counterparts.
Another important certification is Cradle to Cradle Certified®, which stands for continuous recycling management where no waste is generated. Products with this certification are evaluated across five sustainability areas: Material Health, Product Circularity, Clean Air & Climate Protection, Water & Soil Stewardship, and Social Fairness. Threads with Gold or Platinum certification represent the highest environmental standards.
Understand the thread’s end-of-life impact
To determine if sewing thread is biodegradable, consider its complete lifecycle. Threads certified under OEKO-TEX® guarantee they’re free from harmful substances, ensuring human-ecological safety throughout production. This is especially important for items with direct skin contact.
Cradle to Cradle certified threads can either be 100% composted or 100% reprocessed, producing no waste. Some manufacturers have developed threads specifically designed for disassembly solutions, like Coats EcoCycle, which enables easier garment recycling.
Match thread type to garment use
Ultimately, the best sustainable thread depends on your project’s requirements. For environmentally conscious sewists, consider these options:
- Organic cotton thread: Ideal for projects requiring biodegradability, free from harmful dyes and chemicals
- Recycled polyester thread: Made from plastic bottles, offering durability while being more sustainable than virgin polyester
- Hemp or bamboo threads: Excellent choices for environmentally friendly projects requiring strength
Remember that sustainability doesn’t mean sacrificing quality. Many eco-friendly threads perform just as well as traditional options. For water-repellent applications, look for environmentally compatible alternatives that replace harmful per- and polyfluoroalkyl substances (PFAS).
Conclusion
Choosing biodegradable sewing thread ultimately comes down to understanding what you’re working with. Throughout this article, we’ve seen that the material composition determines a thread’s environmental impact. Natural fibers like cotton, silk, linen, and jute break down within months rather than centuries, while conventional polyester might persist for over 200 years in landfills.
Sustainability-minded sewists now have more options than ever before. Organic cotton threads offer a biodegradable alternative without harmful chemicals. Additionally, innovative solutions like Coats’ EcoRegen lyocell thread provide excellent performance characteristics while remaining fully biodegradable. Even recycled polyester threads with special additives represent steps toward reducing environmental impact.
Certifications serve as your best guide when navigating eco-friendly claims. Look specifically for GOTS, GRS, or Cradle to Cradle certifications to ensure the threads meet rigorous environmental standards. These independent verifications matter far more than marketing buzzwords or vague sustainability claims.