Comparison Chart: Natural vs Synthetic Fibers

No, the reality is far more nuanced than typical marketing claims. Conventional cotton uses between 7,000 and 10,000 liters of water per kilogram according to the Water Footprint Network, with a carbon footprint of 5.9 kg CO2-eq/kg per the Textile Exchange 2023 report. By comparison, virgin polyester emits approximately 6.4 kg CO2-eq/kg, a surprisingly modest gap. European linen (grown in France, Belgium, Netherlands) requires virtually no irrigation and has a carbon footprint of just 1.4 kg CO2-eq/kg according to ADEME. Hemp performs similarly at 1.6 kg CO2-eq/kg with additional carbon sequestration in soils. Merino wool has a complex profile: low water footprint (17 liters/kg) but high methane emissions from sheep farming. A complete lifecycle analysis (ISO 14040/14044) must account for cultivation, processing, transport, use phase and end-of-life. A poorly farmed natural fiber shipped 12,000 km can have a worse footprint than locally produced recycled polyester. The key is to prioritize certified fibers (GOTS, EU Ecolabel) and verify geographic origin.

Polyester accounts for 54% of global fiber production in 2023, roughly 60 million tonnes according to Textile Exchange. Its dominance stems from extremely low production costs: approximately 1.20 USD/kg compared to 2.50 USD/kg for cotton and 8-12 USD/kg for silk. Its abrasion resistance reaches 60,000 Martindale cycles, it dries in 45 minutes versus 4 hours for cotton, and retains its shape after 500 washes. For the fast fashion industry, these properties are decisive: low cost, high performance, easy care. However, polyester releases between 700,000 and 6 million microfiber particles per wash cycle according to a Plymouth University study. These microplastics contaminate oceans and enter the food chain. Furthermore, polyester is petroleum-derived (1.5 kg of crude oil per kg of fiber) and takes 200-400 years to decompose in landfill. Recycled polyester (rPET) reduces emissions by 75% compared to virgin, but does not solve the microplastic problem. The European REACH regulation and the upcoming 2025 textile directive may force brands to internalize these externalities in the final price.

Tencel (a registered trademark of Lenzing AG) is a lyocell fiber produced from eucalyptus pulp in a closed-loop process that recovers 99.7% of the NMMO solvent. Its water footprint is 80% lower than conventional cotton according to Lenzing data. In terms of properties, Tencel offers 50% higher moisture absorption than cotton, a silky hand feel comparable to silk, and tensile strength of 40 cN/tex when dry. Its fineness of 1.3 dtex allows extremely fine weaves suited to luxury textiles. However, Supima or Sea Island cotton (extra-long staple fibers of 35-40 mm) remains unmatched for certain applications like luxury shirting, thanks to its natural luster and exceptional dyeability. Tencel wrinkles less than cotton (wrinkle index 3.5/5 versus 2/5 for cotton) and offers natural antibacterial properties certified by the OEKO-TEX 100 standard. For Misciano, a Tencel-silk blend (70/30) represents an ideal compromise: Tencel drape combined with silk luster. The main limitation remains price: 4-6 USD/kg for Tencel versus 2.50 USD/kg for conventional cotton, though the gap is narrowing as production volumes increase.

All three fibers belong to the regenerated cellulosic family, but their manufacturing processes differ considerably. Viscose (invented in 1894) uses carbon disulfide (CS2), a toxic solvent of which 30-40% is released into the atmosphere according to the Changing Markets Foundation report. Modal (developed by Lenzing in 1964) uses the same process but with certified beechwood and higher yield: 10 tonnes of fiber per hectare versus 1.5 tonnes for cotton. Tencel/Lyocell (patented 1988, commercial production 1997) uses NMMO, a non-toxic organic solvent recycled at 99.7% in a closed loop, which earned it the European Award for the Environment. In terms of performance, Tencel offers dry tenacity of 40 cN/tex (vs 22 for viscose and 35 for modal), and wet strength at 85% of its dry strength (vs only 50% for viscose, which becomes fragile when wet). Modal offers superior drape with an initial modulus of 4.5 cN/tex. All three fibers are biodegradable, but only Tencel holds USDA BioPreferred certification with 100% bio-based content. To identify these fibers in a garment, EU regulation 1007/2011 mandates precise labeling: "viscose", "modal" or "lyocell" must appear distinctly.

Silk possesses unique thermoregulatory properties among all textile fibers. Its fibroin (protein) structure contains micro air pockets that insulate in winter and ventilate in summer, maintaining skin temperature between 32 and 34 degrees Celsius. Silk moisture absorption reaches 30% of its own weight without feeling damp, compared to only 0.4% for polyester. This is why polyester creates a "sticky plastic" sensation in warm weather. Silk has a thermal comfort index (Tog) of 0.8 per thin layer, ideal for layering. Polyester, in contrast, has a Tog of 0.5 and barely breathes (water vapor permeability of 3,000 g/m2/24h versus 8,000 for silk). In terms of hand feel, silk has a friction coefficient of 0.15 (very smooth) versus 0.25 for polyester. The sericin proteins present in raw silk have skin-moisturizing properties, recognized by studies published in the Journal of Dermatological Science. However, polyester outperforms silk in durability (60,000 vs 15,000 Martindale cycles) and ease of care (machine washable at 40 degrees vs dry cleaning for silk). For daily wear, a silk-polyester blend (85/15) offers silk comfort with improved mechanical resistance.

The answer depends on the recycling method and the fiber type. Mechanically recycled polyester (rPET, made from plastic bottles) retains 90-95% of virgin polyester mechanical properties according to Repreve data. Its tensile strength is 45 cN/tex versus 48 for virgin, a negligible difference. Chemical recycling (depolymerization followed by repolymerization) produces polyester strictly identical to virgin, but costs 2-3 times more. For recycled cotton, the situation differs: the mechanical shredding process shortens fibers from 28 mm (virgin cotton) to 15-18 mm, reducing yarn strength by 30-40%. This is why recycled cotton is generally blended with virgin cotton (50/50 ratio) or recycled polyester to maintain acceptable performance. Recycled wool (shoddy) loses approximately 50% of its strength but retains thermal properties. The Textile Exchange 2023 Report indicates that recycled fibers represent 8.4% of global production, growing 12% annually. The GRS (Global Recycled Standard) certifies minimum recycled content (50%) and social production conditions. For the consumer, a GRS-certified rPET garment offers near-identical durability to virgin, with 75% fewer CO2 emissions and 60% energy savings.

Atopic or reactive skin requires fibers with low allergenic potential, a smooth surface and good moisture management. Silk ranks first: its fibroin proteins are biocompatible with human skin, and clinical studies published in the British Journal of Dermatology show a 40% reduction in eczema flares among patients wearing silk undergarments. Tencel is also recommended by dermatologists: its nanofibrillar surface (2-4 nm fibrils) prevents bacterial proliferation, and it has achieved OEKO-TEX Standard 100 Class I certification (direct contact with baby skin). Organic cotton certified GOTS is a safe choice, provided it has not undergone anti-wrinkle treatment with formaldehyde (OEKO-TEX limit: 75 ppm for skin contact, 20 ppm for babies). Fibers to avoid absolutely: raw wool (fibers over 30 microns that irritate cutaneous nerve endings), acrylic (static charges and poor absorption), and any textile treated with releasable azo dyes (REACH Regulation Annex XVII). Cashmere (14-16 microns) is hypoallergenic because its fibers are too fine to trigger the itch reflex (threshold at 25 microns). To maximize comfort, prioritize OEKO-TEX certified dyes and finishes free from PFAS and brominated flame retardants.

European linen is indeed one of the most virtuous fibers environmentally, but nuance is needed. Grown primarily in northern France (80% of global linen fiber production), Belgium and the Netherlands, it requires no artificial irrigation (sufficient rainfall of 700 mm/year), very few pesticides (5 times less than cotton) and zero GMOs. Its carbon footprint is 1.4 kg CO2-eq/kg according to ADEME, compared to 5.9 for cotton and 6.4 for polyester. One hectare of flax sequesters 3.7 tonnes of CO2 and the entire plant is utilized (long fibers for textiles, tow for insulation, seeds for oil). However, retting (the bacterial decomposition process to separate fibers from the stem) can pollute waterways if poorly managed, though field retting (standard European practice) is far cleaner than water retting. Mechanical scutching uses minimal energy (0.5 kWh/kg). The limitation of linen is its pronounced wrinkling (index 2/5) and the fact that only 15-20% of the stem becomes long textile fibers. European Flax and Masters of Linen certifications guarantee traceability and good farming practices. In terms of longevity, linen gains softness and beauty with each wash, making it a durable investment.

The correlation between price and quality is real but non-linear in textiles. Cotton at 2.50 USD/kg (conventional) versus Supima cotton at 8 USD/kg differ enormously: staple length (25 mm vs 35 mm), strength (28 cN/tex vs 38 cN/tex), uniformity (coefficient of variation 15% vs 8%). Virgin polyester at 1.20 USD/kg and GRS-certified recycled polyester at 2.80 USD/kg offer nearly identical mechanical performance, the price gap reflecting collection, sorting and processing costs. Silk best illustrates this relationship: Mulberry silk grade 6A (purest, 22-25 denier, zero defects) costs 80-100 USD/kg, versus 30 USD/kg for grade 2A. The difference shows in luster (light reflection of 45% vs 25%), fiber uniformity and wear resistance. For cashmere, prices range from 80 to 200 EUR/m depending on fineness (14 microns for premium vs 19 microns for entry-level) and origin (Inner Mongolia vs industrial blend). Beware the "false bargain": a cashmere sweater at 30 EUR uses short fibers (mechanical recycling) that pill within 5 washes. ISO standard 17751 defines cashmere grades and enables price-quality verification. The best indicator remains cost per wear: a linen garment at 150 EUR worn 200 times costs 0.75 EUR/wear, versus 2 EUR/wear for a polyester piece at 30 EUR worn 15 times.

Fiber durability is measured through several standardized indicators: abrasion resistance (Martindale test, ISO 12947), tensile strength (ISO 13934), dimensional stability after washing (ISO 6330) and pilling resistance (ISO 12945). Nylon leads with 60,000 Martindale cycles and tensile strength of 55 cN/tex, explaining its use in technical wear and leather goods. Polyester follows with 50,000 Martindale and excellent dimensional stability (shrinkage below 1% after 50 washes). Among natural fibers, linen excels with 25,000 Martindale and a unique property: it gains 20% strength when wet, unlike cotton which loses 10%. Hemp reaches 22,000 Martindale with UV resistance superior to all other natural fibers. Silk offers 15,000 Martindale but is sensitive to UV and acidic perspiration. Standard cotton ranges from 10,000-15,000 Martindale, while Supima cotton reaches 20,000 thanks to its long staple fibers. Cashmere, despite its softness, is fragile: 3,000-5,000 Martindale with a tendency to pill (grade 2-3/5). To maximize garment life, the determining factor remains care: washing at 30 degrees, flat drying and storage away from light extends garment life by 40% according to WRAP (Waste and Resources Action Programme) data.

Textile certifications cover two distinct dimensions: the chemical composition of the finished product and production conditions. OEKO-TEX Standard 100 (established 1992, over 20,000 certified companies) tests the finished product for more than 350 harmful substances, with strict thresholds by contact class: Class I (babies, formaldehyde max 20 ppm), Class II (skin contact, 75 ppm), Class III (no skin contact, 300 ppm) and Class IV (decorative materials). GOTS (Global Organic Textile Standard) is more demanding: it certifies that 95% of fibers (organic label) or 70% (made with organic label) are biological, and imposes environmental criteria (wastewater treatment, prohibition of certain dyes) and social criteria (working conditions compliant with ILO). The EU Ecolabel certification (ISO 14024 Type I standard) covers the entire lifecycle and prohibits CMR substances (carcinogenic, mutagenic, reprotoxic). Bluesign (developed in Switzerland) focuses on the production chain: chemical management, resource efficiency, worker safety. OEKO-TEX STeP certification (Sustainable Textile Production) evaluates production sites across 6 modules: chemical management, environmental performance, environmental management, social responsibility, quality and health safety. For consumers, the reliability hierarchy is: GOTS stricter than EU Ecolabel stricter than OEKO-TEX Standard 100 stricter than no certification. A garment with no certification may contain up to 8,000 different chemical substances according to Greenpeace.

The future of textiles is taking shape around three converging axes. First axis, bioengineering: companies like Bolt Threads produce synthetic spider silk (Microsilk) through yeast fermentation, with mechanical properties surpassing natural silk (strength of 1.1 GPa vs 0.6 GPa). Spiber in Japan commercializes Brewed Protein, a programmable protein fiber whose molecular structure is adjustable by application. Modern Meadow develops bio-fabricated collagen for leather without animal farming. These innovations remain costly (200-500 USD/kg) but costs are decreasing by 30% annually according to McKinsey. Second axis, return to heritage fibers: linen, hemp and nettle are experiencing a renaissance. Hemp textile production increased by 40% in Europe between 2020 and 2023. Nettle (Urtica dioica) produces 50 mm fibers, finer than linen, grown without pesticides or irrigation. Kapok (fiber from the kapok tree fruit) is being explored as an alternative to synthetic down. Third axis, circular economy: Renewcell technology transforms old cotton garments into a cellulosic pulp (Circulose) usable to produce new viscose fibers. Infinited Fiber produces Infinna, a cellulosic carbamate fiber from cotton textile waste. The European directive on sustainable textiles (expected 2025-2026) will mandate a Digital Product Passport (DPP) with full traceability from fiber to finished garment, in compliance with ISO 59040 on circular economy.