What Are Clothes Made Of? A Health-First Guide
Every garment is made from fibers, which are tiny threads that fall into two main categories: natural or synthetic. Natural fibers like cotton come from plants and animals, while synthetics like polyester are a form of plastic made from petroleum. What touches your skin all day is a combination of these fibers and the chemicals used to create and finish them, which has direct implications for your personal health.
What People Commonly Assume
It's common to think that "100% natural" on a label automatically means a garment is healthier and safer. That’s a reasonable assumption. A material grown from the earth feels intuitively cleaner than one created in a lab.
However, a fiber's origin is only the first chapter of its story. The journey from a cotton field to a finished t-shirt often involves pesticides, intensive water use, and a range of chemical dyes and finishes that are not disclosed on the tag. The health profile of a garment depends on its entire production process, not just its source material.
The Tradeoffs: Natural vs. Synthetic Fibers
Choosing between materials involves weighing a series of tradeoffs. No fiber is universally "good" or "bad"; the context of how and where you wear it matters.
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Natural Fibers (Cotton, Linen, Wool): The primary health advantage is breathability, which helps regulate moisture and can reduce skin irritation. These materials also do not shed microplastics. The potential concerns often stem from the agricultural stage (pesticide use in conventional cotton) and processing (certain dyes or anti-wrinkle finishes containing formaldehyde).
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Synthetic Fibers (Polyester, Nylon): These plastic-based textiles are durable and often cheaper. The most significant health-related issue is the constant shedding of microplastics—tiny plastic particles—with every wash. These particles contaminate indoor air and dust, leading to potential inhalation. There are also concerns about chemical additives, such as the heavy metal antimony used in polyester production, and certain disperse dyes known to be skin sensitizers.
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Semi-Synthetic Fibers (Rayon, Lyocell): These start as natural wood pulp but are transformed through an intensive chemical process. The key tradeoff here is the manufacturing method. Traditional rayon production uses toxic solvents that can harm workers and may leave residues. In contrast, lyocell (like TENCEL™) is made in a closed-loop system that recycles its less-toxic solvent, resulting in a much cleaner final fabric.
Understanding Chemical Finishes
Beyond the fiber itself, many garments are treated with chemicals to add performance features. These finishes are rarely, if ever, listed on the label.
Common Additives
- PFAS: A class of "forever chemicals" used for water and stain resistance on outerwear and uniforms. Certain PFAS are linked to a range of health issues, and skin contact is one route of exposure.
- Formaldehyde-releasing resins: Applied to create a "non-iron" or "wrinkle-free" effect. Formaldehyde is a known skin irritant and carcinogen, though the amount on clothing is typically low and decreases with washing.
- Azo Dyes: A large category of colorants used across the industry. While most are considered safe, a small number can break down and release carcinogenic compounds.
What This Means in an Everyday Context
Consider a polyester fleece jacket, a common household staple. It is warm and dries quickly, but it releases hundreds of thousands of microplastic fibers in a single wash.
These fibers become part of the dust in your home that you breathe in. This is a clear example of where the convenience of a synthetic material creates a persistent, low-level exposure risk in your immediate environment. The long-term health effects of inhaling microplastics are an area of active scientific research.
What to Look For on Labels
A clothing tag is the closest thing you have to an ingredient list. While incomplete, it provides a crucial starting point for an informed decision.
- Check the fiber content first. A "100% natural" fiber like linen or organic cotton means no microplastic shedding. A "100% synthetic" like polyester is a plastic textile. Blends will still shed microplastics.
- Look for health-focused certifications. These act as a third-party check for harmful chemicals that are not required to be disclosed on the label.
- OEKO-TEX STANDARD 100: Verifies that the final product has been tested and found free from harmful levels of over 100 specific substances.
- Global Organic Textile Standard (GOTS): Ensures the fiber is certified organic and restricts the use of toxic chemicals throughout the entire manufacturing process.
Key Takeaways
- All clothing is made from natural fibers (from plants/animals) or synthetic fibers (from petroleum).
- The primary health concerns with synthetics are microplastic shedding and chemical additives.
- Natural fibers are generally more breathable but can carry a chemical load from pesticides and processing.
- Chemical finishes for features like wrinkle-resistance are not disclosed on labels, making third-party certifications the best guide.
- No material is perfect; every choice involves weighing different health and environmental tradeoffs.
Limitations and Uncertainty
This analysis is based on publicly available research and material science. It is not a substitute for medical advice.
- Retailer Disclosure Gaps: Brands are not legally required to disclose chemical finishes, dyes, or processing agents on clothing labels.
- No Lab Testing Performed: Our assessment relies on existing data, not direct laboratory testing of individual garments.
- Research Is Evolving: The science on the long-term health effects of microplastic exposure and low-dose chemical absorption through skin is still developing.
- Individual Sensitivity Varies: Reactions to materials and chemicals can differ significantly from person to person.
At Greener Closet, we analyze the materials and chemicals in clothing to help you understand the health tradeoffs. Our scoring system is designed to provide clarity on what you're buying.