We check food labels, filter our water, and scrutinize our skincare ingredients. But when was the last time you thought about what your clothes are doing to your body? The average person wears clothing for 12 or more hours a day — and that fabric is in constant contact with your skin, your largest organ. What it’s made of, and what chemicals were used to produce it, matters deeply.

This guide isn’t about fear. It’s about empowerment. You don’t need to throw out your entire wardrobe tomorrow. Small, intentional swaps over time can make a meaningful difference to your health — and to the health of your children. Think of it as a gentle upgrade, not an overhaul.

As Hannah Dunning, founder of The Hannah Dunning Project and known in the clean living world as The Clean Clothing Chick, puts it: getting 1% better every day is all it takes. The journey starts here.

The Problem with Polyester

Polyester is a plastic — specifically, polyethylene terephthalate (PET) — derived from petrochemicals. It currently accounts for roughly 52% of global fiber production, and it’s in everything from activewear to underwear to children’s pajamas. Its affordability and durability have made it the darling of fast fashion, but there’s a growing body of research pointing to some real concerns for human health.

Microplastics & Skin Absorption

Every time polyester is washed, it releases microplastic fibers. Research estimates that a single laundry cycle can release nearly 500,000 microscopic fibers, contributing to an estimated 176,500 metric tons of synthetic microfibers annually. These particles have been detected in human blood, lung tissue, placentas, and even breast milk.

But it’s not just washing that’s the issue. According to Hannah Dunning’s research, when polyester clothing is exposed to body heat and friction — during a workout, on a warm day, or even just sitting at your desk — it begins to shed those microplastics directly onto and into the skin. Sweat opens pores and can carry these particles into the body’s systemic circulation.

Hormone Disruption: A Hidden Threat

Polyester contains chemical additives — including phthalates, BPA, PFAS ("forever chemicals"), and flame retardants — that are classified as endocrine disruptors. These chemicals can mimic or block hormonal signals in the body, affecting everything from metabolism and mood to reproductive function.

Research has linked synthetic clothing chemicals to:

•       Reduced sperm count and motility in men (some studies found azoospermia — a complete absence of sperm — in subjects who consistently wore polyester underwear)

•       Lower testosterone levels associated with phthalate exposure

•       Hormone imbalances that can affect fertility, mood, and thyroid function in women

•       Increased risk of skin irritation, contact dermatitis, and fungal infections due to heat and moisture retention

•       Potential disruption of the developing endocrine systems of children and infants

Hannah Dunning’s research on women’s hormones specifically highlights the concern around bras — garments worn directly over breast tissue, which contains some of the body’s most sensitive endocrine receptors. With breast-related health challenges on the rise, this proximity matters.

Your Workout Clothes May Be the Biggest Offenders

This is one of Hannah Dunning’s most important insights: your workout clothes are likely the most chemical-laden items in your home — and you wear them while sweating. Heat dramatically increases the rate at which polyester releases its chemical load. If you exercise daily (and you should!), those garments deserve your attention first. Prioritizing underwear, bras, and socks — items in direct skin contact — is a practical and effective starting point.

What About Conventional Cotton?

Cotton sounds natural, and in its pure form it is. But conventional (non-organic) cotton farming is one of the most pesticide- and herbicide-intensive agricultural industries in the world. As Hannah Dunning has noted, cotton crops are routinely drenched with insecticides and pesticides during growing and harvesting — and those chemicals travel far beyond the farm.

The Chemical Treatment Problem

Beyond the farming process itself, most conventional cotton clothing is then treated with a cocktail of chemicals during manufacturing to achieve properties like:

•       Wrinkle resistance (often achieved with formaldehyde-releasing compounds)

•       Stain and water repellency (frequently using PFAS — the same "forever chemicals" found in polyester)

•       Fade resistance, static resistance, and anti-odor treatments

•       Synthetic dyes and brightening agents

That distinctive "new clothing" smell? It’s almost always chemicals. If that smell lingers after washing, the chemicals haven’t fully left. For this reason, it’s always worth washing all new clothing before wearing it — especially for children.

Special Concern for Children

Children’s bodies are smaller, their detoxification systems are still developing, and they spend more time close to the ground where chemical concentrations can be higher. Their skin is also more permeable than adult skin, meaning chemical absorption happens more readily. Exposure to pesticide residues and chemical finishes in clothing has been linked in some research to increased ADHD risk and developmental concerns. Dressing children in GOTS-certified organic cotton — especially in sleepwear and items worn directly against the skin — is one of the most meaningful upgrades a parent can make.

The Good News: GOTS-Certified Organic Cotton

Here’s where the story gets genuinely exciting. Choosing GOTS-certified organic cotton isn’t a sacrifice — it’s an upgrade in every sense of the word. GOTS stands for the Global Organic Textile Standard, the world’s leading processing standard for organic fibers. It covers the entire supply chain — from the farm to the finished garment — ensuring no toxic pesticides, synthetic fertilizers, or harmful chemical treatments are used at any stage.

What GOTS Certification Actually Means

•       No synthetic pesticides or herbicides in farming

•       No formaldehyde, PFAS, phthalates, or azo dyes in processing

•       No bleaching with chlorine — safer whitening methods only

•       Restricted use of heavy metals in dyes

•       Certified at every step of the supply chain, not just at the farm

When you see that GOTS label, you can trust that what’s against your skin — and your child’s skin — has been rigorously vetted for your safety.

Health Benefits for Adults

Organic cotton is breathable, hypoallergenic, and naturally moisture-wicking. Its hollow fiber structure allows airflow and reduces the heat buildup that encourages skin irritation and bacterial overgrowth. Studies have shown that sleeping in or wearing organic cotton can meaningfully improve skin hydration and support a healthier skin barrier — a finding especially relevant for adults with eczema, psoriasis, or sensitive skin.

From a hormonal health perspective, removing synthetic fibers and chemical-laden conventional cotton from daily wear reduces the overall toxic load your body has to process. This matters especially for women, whose endocrine systems are particularly sensitive to chemical disruption. As Hannah Dunning emphasizes, small reductions in your daily toxic burden — combined across clothing, food, and personal care — can have a meaningful cumulative impact on how you feel and function.

Health Benefits for Children

For children, the case is even clearer. GOTS-certified organic cotton clothing provides a cleaner, gentler surface for sensitive and developing skin. It’s the standard many pediatric dermatologists recommend for babies and toddlers prone to rashes, eczema, or allergic reactions. Without the chemical finishes found in conventional garments, there’s no formaldehyde off-gassing from pajamas, no synthetic dye irritation in onesies, and no PFAS residue in the items children wear closest to their bodies.

How to Transition — Without Overwhelm

You don’t have to change everything at once. The goal is progress, not perfection — getting 1% better, one swap at a time. A simple way to think about where to start: prioritize items that combine high skin contact, long daily wear time, and broad body coverage. That combination is where your toxic exposure is highest, and where cleaner choices make the biggest difference.

The Top-Priority Items

These are the garments that score highest across all three factors — and the ones worth swapping first:

•       Bras — worn directly against breast tissue for most of the day, close to highly sensitive endocrine receptors

•       Underwear — constant, all-day contact with some of the body’s most sensitive and absorptive areas

•       T-shirts — worn daily by virtually everyone, directly against bare skin, covering the chest, back, stomach, and arms for most of your waking hours. When you consider that most people are dressed for 14–16 hours a day, the sheer surface area makes this one of the highest cumulative exposure items in any wardrobe

•       Children’s sleepwear and bodysuits — worn for 10–12 hours straight against developing skin

Next Swaps to Work Toward

•       Socks — especially during workouts when heat increases chemical release

•       Bedding (sheets, pillowcases) — you spend 7–9 hours in bed each night

•       Activewear — replace as pieces wear out

As you transition, wash all new garments before wearing them — even organic ones — to remove any residual handling chemicals. True outer layers like zip-up hoodies, blazers, and winter coats that sit over other clothing are a lower priority. Focus your energy where skin contact is greatest.

Your wardrobe is one of the most underrated levers in your health toolkit. It doesn’t require a complete lifestyle overhaul — just awareness, and a willingness to make better choices as opportunities arise. The research Hannah Dunning has championed through The Hannah Dunning Project makes one thing clear: what you wear matters. And the good news is, the better choice — soft, breathable, chemical-free GOTS-certified organic cotton — is also simply a nicer way to get dressed.

Swap with intention. Wear with confidence. And enjoy the journey.

Resources

Hannah Dunning — Primary Resource

The Hannah Dunning Project (Podcast)

Available on Spotify and Apple Podcasts. Hannah Dunning explores non-toxic living, clean clothing research, and practical health upgrades for everyday life.

https://open.spotify.com/show/7JqMH3FY5Ku1ZeX1Vnrdou

"Dressed to Kill: American Clothing Is Big Chem’s Favorite Playground"

Culture Apothecary with Alex Clark, March 2026. Hannah Dunning discusses polyester, formaldehyde, lead, PFAS, and forever chemicals in clothing.

https://podcasts.apple.com/zm/podcast/dressed-to-kill-american-clothing-is-big-chems-favorite/id1507839530?i=1000757617385

"The Hidden Chemicals in Clothing: What Every Consumer Needs to Know" (Ep. 102)

Toxin Free(ish) Podcast with Wendy Kathryn, February 2025. Hannah Dunning discusses BPA, phthalates, formaldehyde, microplastics, and how to detox your wardrobe practically.

https://toxinfreeish.com/blog/hidden-chemicals-in-clothing/

"What’s In Our Underwear?" — The Hannah Dunning Project Podcast

Hannah Dunning in conversation with Dan Baird, founder of NADS organic underwear. Discusses organic cotton underwear and its health implications.

https://open.spotify.com/episode/76GH5fKJfDVU0IOAW2bi9p

The Hannah Dunning Project on Instagram

@thehannahdunningproject — Resources, recommendations, and non-toxic living guidance.

https://www.instagram.com/thehannahdunningproject/

•       Global Organic Textile Standard (GOTS): www.global-standard.org

•       Textile Exchange Fiber Market Report 2022 — global polyester production data

•       Napper & Thompson (2016) — microfiber release per laundry cycle, Environmental Science & Technology

•       Leslie et al. (2022) — microplastics detected in human blood, Environment International

•       Ragusa et al. (2022) — microplastics in human breast milk, Polymers

•       Saxena et al. (1990) — polyester underwear and sperm count/motility

•       Orbasics: "Chemicals in Clothing: Is Polyester an Endocrine Disruptor?" (2025): orbasics.com