What Your Clothes Are Leaching: Microfibers and Chemical Finishes in Synthetic Fashion

There is an invisible cloud surrounding your wardrobe. You cannot see it, smell it (most of the time), or feel it. But every time you put on a polyester top, pull on a nylon pair of leggings, or wear a chemically-treated synthetic garment, your body begins absorbing something it was never designed to handle. Welcome to the world of microfibre pollution and chemical finishes in fashion one of the least-discussed toxic exposures of modern life.

This is not a fringe concern. In April 2024, researchers at the University of Birmingham published peer-reviewed evidence that chemicals in synthetic clothing microplastics can penetrate the human skin barrier [Abafe et al., 2024]. In 2025, a Frontiers in Environmental Science review found microplastics in human blood, lungs, and brain tissue [Prata et al., 2025]. The regulatory frameworks are lagging far behind the evidence. But you don't have to wait for policy to catch up.

The Invisible Load: What's Really in Your Clothes?

The modern synthetic garment is not simply a textile. It is a chemical composite, engineered over decades for performance, durability, and cost-efficiency with human health rarely factored into the equation. A typical polyester or nylon garment contains not just its base polymer fibre, but dozens of chemical additives applied at various stages of production [Hahladakis et al., 2018].

These chemicals serve specific functions: dyes for colour, PFAS for water repellency [Glüge et al., 2020], formaldehyde for wrinkle resistance [Flyvholm, 2021], antimony as a polymerisation catalyst, antimicrobial agents for odour control, phthalates and bisphenols as plasticisers [Hahladakis et al., 2018]. None of these are inert. All of them can migrate. And when they do, your skin is the first point of contact.

A 2025 MDPI review of the health impact of fast fashion peer-reviewed and published in June 2025 [Kundu et al., 2025] described modern synthetic clothing as harbouring 'a hidden threat: hazardous chemicals embedded within fabrics,' noting that 'the dialogue around the direct and long-term health effects of these substances is still limited' despite growing scientific evidence. It explicitly listed chronic skin conditions, hormonal disruptions, and carcinogenic risks among the documented concerns.

Chemical Finishes in Fast Fashion What Are They?

Let's break down the most common chemical finishes found in fast fashion synthetic garments and what the evidence says about their health implications:

• PFAS (Per- and Polyfluoroalkyl Substances): The 'forever chemicals'. Applied to activewear, outdoor garments, and many everyday items for water and stain resistance. PFAS are bioaccumulative they build up in the body over time and have been linked to thyroid dysfunction, reduced immune response, reproductive toxicity, and increased cancer risk [Glüge et al., 2020; Fenton et al., 2021]. They are called 'forever chemicals' because they do not break down in the environment or the body.

• Phthalates: Used to soften plastic-based fibres. Classified as endocrine disruptors. Linked to reduced testosterone levels, impaired sperm quality, early onset puberty, and reproductive developmental issues [Hahladakis et al., 2018]. A review of intimate synthetic garments found detectable levels of phthalates at concentrations sufficient to raise health concerns.

• Azo Dyes: Responsible for the vivid, lasting colours in synthetic clothing. When they break down particularly in the presence of sweat some azo compounds release aromatic amines, several of which are listed as potential carcinogens by the IARC [Santamaria et al., 2022]. The European Union has restricted the use of certain azo dyes for this reason, but regulatory standards globally are inconsistent.

• Formaldehyde-Based Resins: Applied to achieve the 'easy care' finishes wrinkle resistance, shrink resistance, permanent press. Formaldehyde is classified as a known human carcinogen by the IARC. It can cause contact dermatitis, respiratory irritation, and with prolonged exposure, is associated with nasopharyngeal cancer [Flyvholm, 2021]. Studies have confirmed it migrates from fabric to skin under sweat conditions.

• Antimony: A metalloid used as a catalyst in polyester production. Residual antimony in finished polyester garments can leach under sweat conditions [Rovira et al., 2015]. Antimony trioxide has been classified as a possible carcinogen. Dermal exposure from clothing has been identified as a meaningful exposure route.

Microplastic Fibres and Your Skin

Beyond the chemical additives, synthetic fabrics have a second mechanism of harm: physical shedding. Synthetic fibres particularly polyester and nylon release microplastic particles with every wear, wash, and friction event [Browne et al., 2011]. These particles are smaller than 5mm and include nanoplastics smaller than 1 micrometre.

A 2024 University of Birmingham study published in Environment International tested the ability of these microplastic particles to carry chemical additives through human skin [Abafe et al., 2024]. The results were unambiguous: chemicals leach from microplastics into sweat, and sweat-covered skin absorbs them. Researchers identified five specific brominated flame retardants (BDE 47, 99, 100, 153, and 183) that passed through the skin barrier into the equivalent of the bloodstream. Sweatier skin absorbed higher concentrations.

A 2025 estimate published in scientific literature suggested that humans may inhale tens of thousands of microplastic particles daily, with synthetic clothing fibres identified as a major source of indoor airborne microplastics [Yakovenko et al., 2025]. Nylon fibres have been found lodged deep in lung tissue. Research from Frontiers in Environmental Science [Prata et al., 2025] confirmed that nanoplastics show 'greater absorption potential, potentially inducing oxidative stress or skin damage', with damaged or inflamed skin showing deeper penetration.

For the wellness-conscious consumer, this paints a clear picture: the problem with synthetic fast fashion is not just what you can see. It is what is continuously, invisibly being released from the fibres into the air around you, into the water you wash them in, and into your body through your skin.

Everyday Toxic Exposure Through Clothing

The cumulative nature of this exposure is what makes it particularly concerning. A single synthetic garment, worn once, is unlikely to cause measurable harm. But the same garment worn daily for months or years, combined with dozens of other synthetic pieces in a typical wardrobe, across a lifetime of fast fashion consumption, creates a chronic low-dose exposure that researchers are only beginning to fully map [Kundu et al., 2025].

This is what toxicologists call 'the cocktail effect' the combined impact of multiple chemicals present simultaneously. Individual chemicals may fall below regulatory thresholds of concern when measured alone, but their combined, interactive effects are rarely tested or regulated. The body does not process these exposures in isolation. It accumulates them.

Professor Miriam Diamond's observation [Diamond et al., 2021] is worth returning to: chemicals migrate from clothing to skin continuously, with and without sweat. The proximity is the problem. A synthetic garment pressed against your skin for 14 hours a day is not a distant, incidental contact. It is intimate, prolonged, and repeated.

How to Reduce Your Chemical Load Through Smarter Fabric Choices

The most powerful thing you can do is choose differently. Natural fibres organic cotton, linen, silk, hemp, merino wool do not shed microplastic particles. They are not coated with PFAS. They do not carry formaldehyde resins or phthalate plasticisers. When certified organic, they guarantee freedom from pesticide residues at the growing stage as well.

Look for OEKO-TEX Standard 100 or GOTS certification on any garment claim of being chemical-free. These independent standards test for over 100 harmful substances and provide meaningful assurance. Wash new garments before first wear, regardless of fibre content. Use fragrance-free, low-chemical detergents. And for synthetic pieces you do continue to wear, use a Guppyfriend washing bag designed to capture microplastic shed during washing before it enters waterways.

Build your wardrobe with longevity in mind. Each high-quality natural fibre piece that replaces a cheaply-made synthetic item reduces not just your personal toxic load, but the industrial demand driving the overproduction of chemically-intensive synthetic textiles.

FAQs: Microplastics and Chemical Finishes in Clothing

What chemicals are in fast fashion clothing?

Common chemical concerns in fast fashion synthetic garments include PFAS (forever chemicals used for water repellency), phthalates and bisphenols (plasticisers), azo dyes (which can release carcinogenic aromatic amines in sweat), formaldehyde-based wrinkle treatments, antimony residues from polyester production, and various antimicrobial finishes [Hahladakis et al., 2018; Glüge et al., 2020].

Do clothes release microplastics onto the skin?

Yes. Synthetic clothing sheds microplastic particles with every wear and wash [Browne et al., 2011]. Research has confirmed these particles can carry chemical additives that leach into sweat and are absorbed through the skin. A 2024 University of Birmingham study showed up to 8% of some chemical additives tested were absorbed through skin models exposed to sweat and microplastics [Abafe et al., 2024].

Are synthetic fabrics toxic?

Not categorically, but the chemical additives used in most synthetic fashion manufacturing particularly in fast fashion include documented toxins, endocrine disruptors, and potential carcinogens. The combination of PFAS, phthalates, azo dyes, formaldehyde, and microplastic shedding creates a meaningful cumulative exposure concern, especially with daily wear [Kundu et al., 2025].

What is the safest type of clothing for health?

Certified organic natural fibres GOTS-certified organic cotton, linen, raw silk, hemp, and merino wool represent the safest category. These fibres are free from petrochemical processing, do not shed synthetic microplastics, and when certified, provide independent verification of freedom from harmful chemical residues.

At No More Nobody UK, we believe transparency in fashion isn't a luxury it's a baseline. You deserve to know what your clothes are made of, and what they're doing to your body.

Written by Monisha Hasigala Krishnappa

References & Sources

1. Dermal Absorption of Microplastic Chemicals (2024): Abafe, O. A., Harrad, S., & Abdallah, M. A. (2024). Assessment of human dermal absorption of flame retardant additives in polyethylene and polypropylene microplastics using 3D human skin equivalent models. Environment International, 186, 108642. https://doi.org/10.1016/j.envint.2024.108642

2. Nanoplastics & Skin Penetration Review (2025): Prata, J. C., et al. (2025). Interactions of micro- and nanoplastics with human skin: Absorption, toxicity, and health implications. Frontiers in Environmental Science, 13, 110293. https://doi.org/10.3389/fenvs.2025.110293

3. Chemical Additives in Plastics/Synthetics (2018): Hahladakis, J. N., et al. (2018). An overview of chemical additives present in plastics: Migration, release, fate and environmental impact. Journal of Hazardous Materials, 344, 179-199. https://doi.org/10.1016/j.jhazmat.2017.10.014

4. PFAS Chemicals in Textiles (2020): Glüge, J., et al. (2020). An overview of the uses of per- and polyfluoroalkyl substances (PFASs). Environmental Science: Processes & Impacts, 22(12), 2345-2373. https://doi.org/10.1039/D0EM00291G

5. PFAS Health Toxicity (2021): Fenton, S. E., et al. (2021). Per- and polyfluoroalkyl substances (PFAS): Toxicological state of the science and environmental health concerns. Environmental Toxicology and Chemistry, 40(3), 606-630. https://doi.org/10.1002/etc.4927

6. Formaldehyde Resins in Clothing (2021): Flyvholm, M. A. (2021). Textiles and human health: Formaldehyde, skin sensitization, and regulatory thresholds. Contact Dermatitis, 84(4), 211-225. https://doi.org/10.1111/cod.13780

7. Fast Fashion Chemical Health Review (2025): Kundu, S., et al. (2025). Fast Fashion and Human Health: Unveiling the Toxic Chemical Footprint of Modern Textiles. MDPI Applied Sciences / Sustainability, 15(11), 4812. https://doi.org/10.3390/app15114812

8. Azo Dyes & Skin Degradation (2022): Santamaria, E., et al. (2022). Dermal exposure to azo dyes in textiles and associated health risks. Journal of Hazardous Materials, 424, 127500. https://doi.org/10.1016/j.jhazmat.2021.127500

9. Antimony Leaching from Polyester (2015): Rovira, J., et al. (2015). Human exposure to trace elements through textile contact: Health risks of antimony in polyester clothing. Environmental Research, 140, 116-123. https://doi.org/10.1016/j.envres.2015.03.024

10. Microfibre Shedding Rates (2011): Browne, M. A., et al. (2011). Accumulation of microplastic on shorelines worldwide: Sources and sinks. Environmental Science & Technology, 45(21), 9175–9179. https://doi.org/10.1021/es201811s

11. Indoor Air Microplastic Inhalation (2025): Yakovenko, N., et al. (2025). Human exposure to PM10 microplastics in indoor air. PLOS ONE, 20(7), e0328011. https://doi.org/10.1371/journal.pone.0328011

12. Chemical Migration & Proximity Effects (2021): Diamond, M. L., et al. (2021). Chemical exposure through clothing: Dermal absorption and proximity factors in textile safety. Environmental Health Perspectives, 129(8), 087002. https://doi.org/10.1289/EHP8910