References & Understanding
This reference page is designed to give our customers a clear, concise understanding of the scientific research, reviewed and compiled by our team, behind the materials and chemicals commonly found in clothes and their surroundings. Each section will provide valuable context. The subsequent studies in each section will summarize key findings about synthetic fibers, dyes, and chemical treatments, and how they may impact your health and the environment.
On this references & understanding page, you will only find studies that meet our standards of scientific rigor and fact, and form the basis for our claims, and why we strive to create safer and healthier alternatives to what is widely available to the public.
Our commitment is to provide transparency and empower informed choices, by presenting the potential benefits of organic natural materials, supported by scientific research.
Note: All studies referenced on this page have been reviewed for relevance and accuracy by the NADS Research Team based on publicly available data. Some studies are linked below to their publicly available literature abstracts. For full access to paywalled journals, please consult the publisher directly or use institutional access where available. The company is providing its main takeaways from each study to summarize the findings for ease of understanding. These summaries are intended to distill complex scientific research into clear, concise points that highlight key insights relevant to the potential health and environmental impacts of materials and chemicals. While every effort has been made to accurately reflect the essence of each study, these takeaways are not exhaustive analyses and should not replace a full review of the original research. Readers are encouraged to consult the linked studies for detailed information and context.
The health and safety claims presented are based on current research findings, which may have limitations, including sample size, scope, or methodology. Individual results may vary. The information provided here is intended for informational purposes only. It does not constitute medical advice, nor does it guarantee specific health or environmental outcomes. For individual concerns, consult with a qualified professional.
Why You Should Care
Properly sourced, GOTS-certified organic cotton underwear offers a breathable and hypoallergenic alternative that may support healthier skin and overall wellness. In this section, we have outlined key studies that highlight potential health and environmental concerns associated with materials and chemicals commonly used in clothing and textiles.
Endocrine Society Guide
This guide by the Endocrine Society is a great beginner resource that outlines the risks associated with endocrine-disrupting chemicals (EDCs), which are found in everyday products like plastics and personal care items. It discusses how EDCs can interfere with hormone function, potentially leading to health issues such as reproductive disorders, obesity, and developmental problems.
Everyday exposure to EDCs in certain products has been studied for potential effects on hormonal balance and long-term health, though individual impacts may vary.
Study #1
This study examines the environmental impact of synthetic microfiber pollution from textiles, highlighting that fibers from synthetic fabrics like polyester shed into waterways during washing, potentially harming aquatic ecosystems and coming full circle into the human food chain.
Synthetic fabrics contribute to environmental pollution and impact the micro and macro ecosystems.
Study #2
This study investigates how textile materials can impact skin health, specifically examining the skin's reaction to different fibers, dyes, and fabric treatments. It emphasizes that certain chemicals and synthetic fibers can cause irritation and adverse skin reactions, which may be avoided with natural, untreated materials.
Natural, untreated fabrics are gentler on the skin compared to synthetic, chemically treated textiles.
Study #3
This study assesses human exposure to trace elements in clothing materials, such as chromium, antimony, and copper, which are used in dyes, flame retardants, and antimicrobial treatments. While the exposure levels varied among different fabrics, specific materials, especially polyester, showed potential risks due to higher levels of antimony.
Highly processed clothing materials may contain trace elements, and prolonged exposure under certain conditions could pose potential health risks.
Study #4
This research investigates how nano- and microplastics, specifically polystyrene nanoplastics, may disrupt the endocrine system and impair reproductive health. Testing on male rats showed that exposure led to decreased testosterone and other reproductive hormones, DNA damage, and sperm abnormalities, with effects worsening at higher doses. This study underscores the potential long-term risks of microplastic exposure on reproductive health.
Nano- and microplastics can disrupt endocrine function and impair reproductive health, posing a growing public health risk.
Study #5
This research investigates how nano- and microplastics, specifically polystyrene nanoplastics, may disrupt the endocrine system and impair reproductive health. Testing on male rats showed that exposure led to decreased testosterone and other reproductive hormones, DNA damage, and sperm abnormalities, with effects worsening at higher doses. This study underscores the potential long-term risks of microplastic exposure on reproductive health.
This study found a connection between EDC exposure and the following:
Reduced Sperm Quality: Decrease in sperm concentration, motility, and morphology, which negatively impacts male fertility.
Testicular Dysgenesis Syndrome (TDS): Developmental disorder involving low sperm count, undescended testes, and increased risk of testicular cancer.
Polycystic Ovary Syndrome (PCOS): Hormonal imbalance in women leading to irregular periods, infertility, and ovarian cysts.
Obesity: Excessive fat accumulation influenced by EDCs disrupt the hormones regulating metabolism and fat storage.
Type 2 Diabetes: Chronic condition where insulin resistance develops, potentially worsened by EDCs interfering with glucose metabolism.
Thyroid Dysfunction: Imbalance in thyroid hormone production, which affects metabolic rate, growth, and energy levels.
Breast Cancer: There is a higher risk of breast cancer linked to EDCs that mimic estrogen, potentially promoting the growth of cancerous cells.
Prostate Cancer: Increased risk of prostate cancer due to hormonal disruption caused by EDC exposure.
Endometriosis: Painful condition where tissue similar to the uterine lining grows outside the uterus, potentially aggravated by EDCs.
Neurodevelopmental Disorders: Conditions like ADHD and autism, influenced by EDCs affect brain development during critical growth periods.
Reduced Immune Function: Lowered immune system resilience, potentially leading to higher susceptibility to infections and autoimmune diseases.
Early Puberty: Accelerated sexual maturation in children, often due to EDCs mimicking natural sex hormones.
Hypospadias: A birth defect in male infants where the urethra opens on the underside of the penis, potentially linked to prenatal EDC exposure.
Cryptorchidism: Condition where one or both testicles fail to descend, often associated with prenatal exposure to EDCs.
Decreased Bone Density: Weakening of bone strength and density, which may be influenced by hormonal imbalances from EDCs.
Cardiovascular Disease: Increased risk of heart disease and high blood pressure due to metabolic and hormonal disturbances from EDC exposure.
Exploring the Impact of Synthetic plastic-based Materials
List of common plastics found in clothing:
- Polyester: A plastic-based fiber made from PET (polyethylene terephthalate), commonly found in various types of clothing.
- Nylon: A rugged fiber made from synthetic plastic polymers often used in activewear.
- Acrylic: A plastic fiber resembling wool, used in sweaters and knitwear.
- Spandex (aka Lycra or Elastane): A stretchy fiber providing flexibility, used in athletic and tight-fitting clothing.
- Polypropylene: A lightweight, moisture-wicking fiber used in thermal and activewear.
- Polyurethane: A coating material for fabrics and faux leather, adding water resistance.
- Polyvinyl Chloride: A plastic used in synthetic leather and rainwear, known for water resistance.
- Polyethylene: A plastic found in fleece and insulation layers, typically added for warmth.
Concerns about plastic often stem from the introduction of nano- and microplastics into the body, which may lead to potential health effects for some individuals, including irregular body thermoregulation, static charge buildup, skin irritation, exposure to byproducts like bisphenols, and the impact of various chemicals used in the production and treatment of plastics.
The problem with these materials and their byproducts in clothing can be split into two considerations:
- Plastic-based materials
- Manufacturing chemicals
Plastic-based Materials
Electrostatic/Heat
Study #1
This experimental study on dogs analyzed the effects of wearing cotton versus polyester underwear on spermatogenesis over 24 months. Results showed that polyester underwear led to a significant decrease in sperm count and quality, with some degenerative changes in testicular tissue, while cotton underwear and the control group showed no adverse effects. Notably, sperm quality improved after removing polyester garments.
Polyester fabric can impair spermatogenesis, potentially due to electrostatic effects.
Study #2
This study, conducted by Dr. Ahmed Shafik in 1993, explored the effects of various textile materials on sexual activity in male rats. Shafik designed custom-made "pants" for the rats, made of 100% polyester, a polyester-cotton blend, 100% cotton, and 100% wool, to determine if fabric type influenced sexual function. He found that rats wearing polyester or polyester-cotton blends had significantly reduced sexual activity, while those with cotton or wool garments maintained normal function. Shafik attributed this effect to static electricity generated by synthetic fibers, which could interfere with penile nerve function.
Polyester-based fabrics may reduce sexual activity in rats, potentially due to static electricity affecting nerve function.
Study #3
This study tested a polyester scrotal sling as a contraceptive in 14 men, finding that prolonged use induced reversible azoospermia (absence of sperm) within 120-160 days without affecting hormone levels. The azoospermic effect was linked to increased scrotal temperature and electrostatic fields generated by the polyester, and sperm counts returned to normal after the sling was removed.
The use of polyester scrotal slings drastically increased scrotal temperature and exposed users to electrostatic fields, leading to complete, albeit reversible, sperm suppression.
Bisphenols
Study #1
This review discusses the extensive research on Bisphenol-A (BPA) as an endocrine-disrupting chemical. Despite thousands of studies revealing BPA's harmful effects even at doses below current regulatory limits, agencies like the FDA have maintained that low-dose BPA exposure is safe, based on outdated toxicological assumptions. The CLARITY-BPA study, a comprehensive analysis incorporating both traditional and modern toxicology endpoints, found significant adverse effects at low BPA doses, challenging current regulatory perspectives.
Current regulatory approaches fail to adequately assess BPA's low-dose risks, despite substantial evidence of its adverse endocrine effects.
Study #2
This review focuses on the health risks associated with Bisphenol-A (BPA) exposure, particularly through the Wnt signaling pathway, a critical component in cell development and signaling. BPA's structural similarity to hormones like estrogen and thyroid hormone enables it to disrupt the endocrine system, leading to multisystem toxicity, including impacts on reproductive, neurological, hepatic, and renal functions. The central nervous system is notably susceptible, especially during development. The review also highlights how oxidative stress, endocrine disruption, and epigenetic changes contribute to Wnt pathway dysregulation, emphasizing Wnt signaling as a potential therapeutic target to mitigate BPA-related damage.
BPA exposure disrupts critical signaling pathways, particularly Wnt signaling, posing a widespread risk to various bodily systems.
Study #3
This study investigates Bisphenol-A (BPA) and its analogs (BPS, BPB, and BPF) in textiles, assessing potential dermal exposure and health risks. The analysis of 57 samples from recycled and conventional textiles revealed higher median BPA levels in recycled materials, indicating greater contamination in recycled fabrics. Bisphenols were reduced after washing, though exposure from sweat-wet textiles often exceeded safe thresholds set by the European Food Safety Authority.
Recycled textiles have been found to contain higher bisphenol levels in some cases, which may exceed safety thresholds under specific conditions such as prolonged sweat-moistened contact.
Microplastics
Study #1
This study examines the effects of microplastics, particularly those from textiles, on wildlife health and reproduction. It specifically highlights that ingested textile microfibers can lead to physical blockages, inflammation, and reduced reproductive success in various species, raising concerns about the ecological impact of microfiber pollution and implications for human contact with microplastics.
Textile microfibers can harm wildlife health and reproduction, underscoring the ecological risks of microfiber pollution.
Study #2
This review examines the potential health risks posed by nano- and microplastics, which enter the human body through ingestion, inhalation, or skin contact. These particles can bioaccumulate and contribute to various health issues, including respiratory diseases, neurological symptoms, and inflammatory and gut disorders. Research indicates that nano- and microplastics may cause cell apoptosis, genotoxicity, and cytotoxic effects.
The pervasive nature of nano- and microplastics in your environment poses significant health risks.
Study #3
This study investigates the effect of microplastic exposure on human skin cells, focusing on cellular toxicity and oxidative stress. The findings reveal that microplastics can lead to cellular damage, inflammation, and increased oxidative stress markers, affecting skin health with prolonged exposure.
Microplastic exposure can harm skin cells by inducing oxidative stress and inflammation.
Impacts of Synthetic Material Production
The pervasive use of synthetic materials in everyday products has led to widespread exposure to toxins that can pose significant health risks. While companies and regulatory agencies often dismiss this concern, customers should know that while individual impacts vary, daily exposure to even small amounts of manufacturing byproducts and plastic particles can have a cumulative negative effect. This section delves into some of the most concerning chemicals involved in synthetic manufacturing, examining how these substances can leach into the environment and enter our bodies through dermal routes. The focus is on endocrine-disrupting chemicals (EDCs), microplastics, phthalates, and formaldehyde, among others, which have been linked to serious health issues such as reproductive dysfunction, metabolic disorders, and developmental impairments.
Here is a brief outline of the chemicals found in textile manufacturing and their known toxicity:
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Phthalates
Used to make plastics, such as PVC, flexible and soft.
Known endocrine disruptors linked to hormone imbalances, reduced sperm quality, reproductive issues, and developmental disorders. [1]
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Polyvinyl Chloride (PVC)
Used in some synthetic materials for durability and flexibility.
Can release toxic dioxins during manufacture and disposal, affecting respiratory and immune systems and potentially carcinogenic. [1]
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Azo Dyes and Other Synthetic Dyes
Azo dyes are commonly used for bright colors in textiles.
Some of these dyes break down into amines, which can be carcinogenic and lead to skin sensitization and allergic reactions. [1]
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Flame Retardants
Applied to synthetic fabrics to meet fire safety regulations.
Include chemicals like brominated flame retardants and chlorinated paraffins, which are endocrine disruptors linked to developmental issues, reproductive harm, and neurological impairments. [1]
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Polyurethane
Found in spandex, elastane, and Lycra materials for stretchability.
Can release isocyanates, which can cause skin and respiratory irritation and potentially lead to sensitization and asthma. [1]
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Perchlorates
Sometimes used in dyes and finishes.
Known to interfere with thyroid function, leading to hormonal imbalances and developmental issues. [1]
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Styrene and Styrene-Based Compounds
Found in synthetic rubber and some elastic fibers.
Associated with respiratory issues, neurological effects, and classified as a possible human carcinogen. [1]
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Polybrominated Diphenyl Ethers (PBDEs)
Used as flame retardants.
Accumulate in fat tissue, disrupt thyroid hormones, and are linked to reproductive and developmental toxicity. [1]
Overview #1
This comprehensive overview focuses on endocrine-disrupting chemicals (EDCs) and their widespread presence in consumer products, detailing their potential impact on reproductive health, metabolism, and growth. The study discusses in detail the evidence linking EDC exposure to conditions such as obesity, diabetes, and fertility issues, emphasizing the importance of reducing exposure to these chemicals.
Endocrine-disrupting chemicals in everyday products may lead to serious health issues, including reproductive and metabolic disorders.
Study #1
This study examines the combined impact of multiple chemicals—bisphenols (A, S, F), polychlorinated dioxins, paracetamol, and phthalates—on male reproductive health, specifically semen quality. Using urine samples from 98 Danish men, researchers assessed the risk posed by these chemicals collectively rather than individually, applying a mixture risk assessment approach. Results showed that bisphenol A contributed significantly to the risk, but other chemicals like polychlorinated dioxins, bisphenols S and F, and the phthalate DEHP were also notable risk drivers. Removing bisphenol A alone wouldn’t reduce the risk to safe levels due to the impact of other chemicals. The study highlights the need to address exposures to multiple chemical agents simultaneously to mitigate health risks effectively.
Even without bisphenol A, combined exposures to several chemicals can significantly exceed safe levels, underscoring the importance of comprehensive exposure reduction efforts.
Study #2
This study examines the effects of phthalates, chemicals commonly used to make plastics flexible, on human health. It reveals that phthalates can disrupt endocrine function and have been linked to issues like reduced sperm quality, hormone imbalances, and developmental disorders.
Phthalates in plastics can disrupt hormones and harm reproductive health, including sperm quality.
Study #3
This study investigates formaldehyde exposure from textiles in "eco-friendly" and conventional clothing, targeting sensitive groups like pregnant women, babies, and toddlers. Researchers detected formaldehyde in 20% of samples, with levels higher in eco-friendly garments, especially bras and panties for pregnant women. Dermal exposure levels were technically within safety limits, but inhalation remains the primary exposure risk.
Even "eco-friendly" clothing can contain high levels of formaldehyde, and exposure risks should be considered, especially in garments for vulnerable groups.
Study #4
This study used high-resolution mass spectrometry (LC/MS) to analyze the presence of hazardous chemicals in 24 textile garments. The most frequently detected compounds were benzothiazole, quinoline, and phthalates, known for their toxic, carcinogenic, and endocrine-disrupting properties. Other detected chemicals, including nitroanilines and organophosphates.
Chemical residues in textiles can pose health risks, with current insufficient regulatory measures.
Are these toxins actually of concern in clothing?
A point of contention in discussing the health of clothing is the ability of chemicals and plastics to cross into the skin. The studies below elucidate how not only can chemicals and plastic cross the skin barrier, but that the sensitive, highly porous skin in areas such as the scrotum and armpit shows the highest absorption rates in the body. The likelihood of these chemicals penetrating the body increases under conditions that open pores further, like heat and sweat from exercise.
Additionally, synthetic materials trap heat and moisture, further exacerbating skin absorption, irritation, and allergic reactions through prolonged contact with irritants such as formaldehyde, dyes, and flame retardants. Studies highlight that breathable, natural fabrics like cotton mitigate these risks by allowing skin to cool and reducing chemical exposure, making them safer for those seeking to avoid potential dermal absorption of synthetic toxins.
Study #1
This study addresses the dermal exposure risks for agricultural workers using pesticides. It notes that despite the effectiveness of personal protective equipment (PPE) in reducing pesticide absorption through the skin, compliance with PPE use remains low. The study calls for more research on alternative control measures and improved training methods to enhance worker safety.
Effective use of PPE can reduce pesticide exposure, but compliance and proper training are critical for protecting workers' health.
Study #2
This study investigates the permeation and accumulation of benzothiazole, a chemical commonly found in textile materials, through human skin. The researchers showed that benzothiazole can transfer from textiles to skin and penetrate to deeper layers, suggesting possible systemic exposure. The permeation was measured using Franz-type and flow-through diffusion cells, both of which revealed significant accumulation of benzothiazole in skin-simulating membranes, indicating the potential for dermal exposure from contaminated clothing.
The study suggests that common textile contaminants like benzothiazole can penetrate the skin and accumulate within the body, emphasizing the potential health risks of exposure from everyday clothing.
Study #3
This study investigates the presence and dermal exposure risks of bisphenols (BPA, BPS, BPB, BPF) in clothing, including both recycled and conventional materials. Using UHPLC-MS/MS, researchers analyzed 57 textile samples and found notable BPA and BPS concentrations, with higher BPA levels in recycled textiles. Importantly, this study showed that exposure to sweat-moistened textiles could exceed the recommended safety thresholds of chemical additives. While BPA levels generally stayed below the EFSA's daily intake limits in dry fabrics, sweat-soaked conditions often surpassed these limits, indicating increased exposure risk.
These findings highlight the widespread presence of bisphenols in textiles and underscore the potential health risks from bisphenol exposure.
Study #4
The study reviews the potential health impacts of microplastics and additives of concern, highlighting their pervasiveness in environments. Microplastics act as vectors for hazardous chemicals, often containing additives like bisphenols and phthalates to enhance durability. Ingested or inhaled, these particles can carry harmful substances directly into the human body, potentially causing respiratory, endocrine, and reproductive disruptions. The study emphasizes the need for more research on exposure pathways and health risks associated with microplastics.
Microplastics pose significant health risks due to their ability to carry toxic chemicals, highlighting the importance of continued research on exposure and impact.
Study #5
This study demonstrated that quantum dot nanoparticles (QDs) can penetrate the skin barrier in mice. The findings reveal that intact skin shows low-level nanoparticle penetration. This evidence supports the ability of nanoparticles to cross the skin barrier, especially under conditions that weaken skin integrity.
Nano-plastic particles can penetrate the skin barrier.
Study #6
This study used high-resolution mass spectrometry (LC/MS) to analyze the presence of hazardous chemicals in 24 textile garments. These include nitroanilines and organophosphates, demonstrated properties that enable skin absorption. Specifically, these chemicals possess certain molecular weight and lipophilicity that allow them to cross the skin barrier. Such properties mean that when textiles containing these substances are in prolonged contact with the skin, there's a potential for these chemicals to be absorbed, posing health risks through dermal exposure.
Chemical residues in textiles can pose health risks through skin absorption, with current regulatory measures proving insufficient.
Why GOTS organic cotton?
GOTS organic cotton underwear offers a clean, safe alternative to synthetic options that often contain harmful chemicals that can be absorbed through the skin. Unlike synthetics, organic cotton is naturally breathable, reducing moisture buildup and supporting healthy skin. This cotton is grown without pesticides or toxic dyes, making it hypoallergenic and ideal for sensitive skin. GOTS's commitment to purity and sustainability ensures you're protected from unnecessary chemicals while prioritizing comfort and long-term health.
A prime example of the misinformation surrounding synthetic fibers is this OSHA document which details how in hot environments, clothing choice significantly impacts heat stress levels. They go on to say that natural fibers such as cotton and wool are often preferred because they are breathable and allow for better air circulation, which can help in cooling the body. Synthetic fabrics, which have been shown to be equal or slightly worse at designed moisture-wicking and breathability, may trap heat and moisture, potentially increasing the risk of heat-related illnesses which you can see in this double-blind RCT.
Study #1
This study evaluates the environmental impact of using organic cotton versus conventional cotton in jean production. Compared to conventional cotton, the findings showed that jeans made with 100% organic cotton significantly reduced environmental impacts, including a 87% decrease in terrestrial ecotoxicity and a 59% reduction in freshwater ecotoxicity, compared to conventional cotton. The results suggest that both organic cotton and eco-conscious consumer practices are crucial for reducing jeans' overall environmental footprint.
Using organic cotton and mindful care practices can make jean production more sustainable.
Study #2
This study aimed to evaluate whether synthetic "cooling" fabric, claimed to enhance athletic performance by promoting thermoregulation, actually improved endurance exercise outcomes in trained athletes. Conducted as a randomized, double-blind crossover trial, participants wore either a synthetic "cooling" fabric or a control synthetic fabric while performing high-intensity cycling exercises. Results showed no significant differences in exercise endurance or thermoregulatory measures, such as core and skin temperatures, between the two fabric types. Additionally, perceptual factors like comfort and thermal sensation were unaffected, suggesting the cooling fabric did not offer measurable performance or physiological advantages under indoor exercise conditions.
The study indicates that synthetic "cooling" fabrics may not enhance exercise endurance or thermoregulation compared to other synthetic materials during high-intensity indoor activities.
Document #1
The Global Organic Textile Standard (GOTS) report details how GOTS-certified organic cotton adheres to strict standards for chemical control to reduce risks to consumers and the environment. The standard prohibits toxic substances commonly found in conventional textile production, such as heavy metals, formaldehyde, and phthalates, which can cause skin irritation and environmental harm. Additionally, GOTS-certified cotton products are tested to confirm low residual chemical levels, significantly reducing the risk of allergic reactions or health issues linked to prolonged skin contact. This commitment to stringent chemical oversight makes GOTS-certified organic cotton a safer, more skin-friendly alternative to conventional fabrics.
These standards highlight GOTS's emphasis on both safety and ecological responsibility, demanding minimal chemical exposure through strict guidelines.
Document #2
The GOTS (Global Organic Textile Standard) flyer on fibers outlines how GOTS-approved textiles prioritize organic fibers, requiring at least 70% certified organic material in any certified product. GOTS certification ensures that these fibers are free from GMOs, toxic pesticides, and synthetic fertilizers, which are typical in non-organic cotton farming and can harm both the environment and consumers. Additionally, the standard prohibits the use of harmful processing chemicals, like azo dyes and chlorine bleach, further protecting the health of workers and end-users. By focusing on organic, responsibly sourced fibers, GOTS certification supports sustainable agriculture and safer products for everyday wear.
GOTS certification reflects a strong commitment to ethical, eco-friendly practices across the textile industry.
News Articles
The following news articles are included to provide additional context and insights on the topic. While news sources can be valuable for understanding broader perspectives and recent developments, they may not always adhere to the rigorous standards of scientific research. Please approach these sources with an understanding that they complement, but do not replace the rigor of the studies presented above.
The Toxic Truth About A New Generation of Nonstick and Waterproof Chemicals Toxic Threads: The Big Fashion Stitch-Up Organic Cotton: One of the most important choices you can make for the environment