Polyester makes up 52% of all fabric produced globally. It's in your activewear, your sofa, your kids' school uniforms and probably your bedding. Here's what the science says about sleeping in plastic every night.

In This Article

1. What Is Polyester, Actually?
2. The Microplastic Problem: You're Shedding Plastic While You Sleep
3. Skin Irritation, Dermatitis, and Eczema
4. Endocrine Disruption: The Hormone Problem
5. Respiratory Risks
6. PFAS and "Forever Chemicals" in Fabric
7. Why Bedding Specifically Matters
8. The Case for Organic Cotton

What Is Polyester, Actually?

Polyester is a plastic. Specifically, it's polyethylene terephthalate 'PET' the same material used to make single-use drink bottles. It's manufactured from petroleum-based chemicals, melted down, and spun into fibres.

It became the dominant global fabric because it's cheap, durable, and wrinkle-resistant. As of 2022, polyester accounted for approximately 52% of global fibre production (Textile Exchange, 2022). You'll find it in sportswear, fast fashion, children's clothing, and critically a huge proportion of sheets, pillowcases, and mattress protectors.

The problem is that what makes polyester convenient for manufacturers creates real concerns for the people wearing and sleeping in it.

The Microplastic Problem: You're Shedding Plastic While You Sleep

Every time synthetic fabric is washed or worn, it sheds tiny plastic particles called microplastics, fragments smaller than 5mm. Research by Napper and Thompson (2016) estimated that a single laundry cycle releases approximately 496,000 microplastic fibres from polyester garments alone.

Those fibres go somewhere. Some enter waterways. Some float in the air of your home. And increasingly, researchers are finding them inside us.

Microplastics in human blood (2022): A study led by Jenner et al. confirmed the detection of microplastics in human blood, including particles of PET the polymer used in polyester fabric. The researchers demonstrated these particles can circulate within the body and potentially cross biological barriers. View on PubMed →

Microplastics in human placentas (2021): A landmark study by Ragusa et al. found microplastic particles embedded in human placental tissue, raising serious questions about fetal exposure during pregnancy and potential risks for developmental health. View on PubMed →

Microplastics in human lung tissue (2021): Researchers have also detected microplastics in lung tissue, liver, kidneys, and breast milk suggesting widespread systemic accumulation from everyday exposure routes including inhalation and skin contact. View on PubMed →

"Studies in cell cultures, marine wildlife and animal models indicate that microplastics can cause oxidative damage, DNA damage and changes in gene activity  known risks for cancer development." — Harvard Medicine

In vitro studies have shown microplastics can induce oxidative stress and inflammation in human cells. Long-term human clinical studies are ongoing but the presence of these particles in virtually every organ and tissue examined so far is significant.

Skin Irritation, Dermatitis, and Eczema

The most immediate and well-documented risk of synthetic fabric contact is skin irritation. Polyester is non-breathable. It traps moisture and heat against the skin, creating conditions that promote bacterial growth, friction-related rashes, and allergic responses.

• Up to 60–70% of individuals with sensitive skin report rashes, itching, or contact dermatitis when wearing synthetic clothing, particularly in warm or humid conditions.
• Between 60–70% of patients with atopic dermatitis (eczema) experience worsened symptoms when wearing synthetic garments.
• Folliculitis (inflamed hair follicles), fungal infections, and heat rash are all associated with prolonged non-breathable fabric contact.

Textile fibre dermatitis (1995): A foundational study by Hatch and Maibach was the first to formally link synthetic fibres to skin sensitisation and allergic contact reactions. More recent research has refined this — pointing specifically to chemical finishing agents like disperse dyes and formaldehyde resins as primary triggers but the irritation risk for sensitive skin is clinically well-established. View on PubMed →

Particularly relevant for babies and children: Infants and toddlers have thinner, more permeable skin barriers, making them significantly more susceptible to irritation from synthetic fabric contact. This is especially relevant for bedding, where skin is in prolonged, direct contact for 10 or more hours at a time.

Endocrine Disruption: The Hormone Problem

Polyester contains and sheds chemical additives including phthalates, bisphenol A (BPA), PFAS, and brominated flame retardants. These are known endocrine-disrupting chemicals (EDCs): they can bind to hormone receptors in the body and interfere with normal hormonal function.

Experimental studies using human skin models have shown that up to 8% of chemical additives such as polybrominated diphenyl ethers (PBDEs) can be absorbed through sweat-moistened skin from microplastic fibres. Heat, friction, and moisture, all conditions present during sleep increase this absorption rate.

Endocrine disruption from micro and nano plastics (2023): A review published in Frontiers in Endocrinology found that microplastics and nanoplastics have damaging impacts on mammalian endocrine components including the hypothalamus, pituitary, thyroid, adrenal glands, testes, and ovaries. MPs were found to act as transport vehicles for harmful chemicals including bisphenols, phthalates, and perfluorinated compounds that leach into surrounding biological tissues. View on PubMed →

Phthalates and male fertility: Research published in Environmental Health Perspectives found associations between higher urinary phthalate levels in men and lower testosterone levels and reduced fertility markers. Phthalates are commonly found in synthetic clothing and fabric finishes. View on PMC →

Plastics, EDCs, and diabetes risk (2023): A 2023 study published in the American Journal of Physiology found that endocrine-disrupting chemicals leached from plastics alter beta-cell function in the pancreas and increase the risk of type 2 diabetes mellitus. View on PubMed →

Respiratory Risks: What You're Breathing at Night

Synthetic fabric fibres don't just contact skin they become airborne. Bedding made from polyester or polyester blends continuously sheds microfibre particles that accumulate in household dust and circulate in bedroom air.

Given that most people spend 7 to 9 hours per night in their bedroom with their face close to the pillow, airborne microplastic exposure from bedding is a meaningful and underappreciated risk. When inhaled, microplastic particles can settle deep within the lungs and may remain lodged for years, potentially contributing to respiratory inflammation. Children, the elderly, and those with pre-existing respiratory conditions face the greatest exposure risk.

Indoor airborne microplastics study (2024): A study examining airborne microplastics in indoor environments found polyester fibres dominated indoor air composition (33% of total particles), with synthetic textiles identified as the primary indoor source. Fibre-type particles were overwhelmingly more prevalent indoors than outdoors, directly reflecting synthetic textile shedding. View on ScienceDirect →

PFAS: The "Forever Chemicals" in Your Fabric

PFAS per and polyfluoroalkyl substances are used in synthetic textiles to create water-resistant and stain-resistant finishes. They're called "forever chemicals" because they don't break down in the environment or in the human body.

Studies suggest PFAS can enter the bloodstream through prolonged skin contact with synthetic fabrics. Chronic PFAS exposure has been linked to thyroid dysfunction, immune suppression, liver disease, and certain cancers.

The challenge with PFAS in bedding specifically is the exposure duration. Unlike activewear worn for an hour at the gym, bedding is in contact with your skin for 8 or more hours every single night across years and decades of use.

Why Bedding Specifically Matters More Than Clothing

There's an important distinction between wearing synthetic fabric during the day and sleeping in it at night. Bedding exposure sits in its own category for several reasons:

• Duration: We spend roughly a third of our lives in bed. No other fabric has that kind of sustained contact with our skin.
• Heat and sweat: Body temperature rises during sleep. Sweat increases chemical leaching from synthetic fibres and is an established route for chemical absorption through the skin barrier.
• Inhalation proximity: Your face is centimetres from the pillow for hours. Airborne microfibre exposure from synthetic pillowcases is direct and continuous.
• Vulnerable populations: Babies and toddlers  with their thinner skin barriers and higher skin surface-to-body-weight ratio spend more time in bedding than anyone else in the household.

The average person spends 26 years asleep. The fabric you choose for your bed isn't a small decision it's one of the highest-volume skin contacts of your entire life.

Ready to get polyester out of your bed? Milk&Bed waterproof fitted sheets are made from 100% GOTS-certified organic cotton - no polyester, no PVC, no PFAS. Waterproof protection that's actually made from fabric you'd want against your family's skin. Shop Milk&Bed →

The Case for Organic Cotton in Bedding

The alternative to synthetic fibres isn't just "any cotton." Conventional cotton is one of the most pesticide-intensive crops on earth, so the certification matters.

GOTS-certified organic cotton (Global Organic Textile Standard) means the fibre has been grown without synthetic pesticides or fertilisers, and processed without harmful chemical finishes, formaldehyde resins, or toxic dyes. It's the gold standard for fabric you want against skin you actually care about.

Compared to polyester, organic cotton:

• Sheds zero microplastics
• Contains no phthalates, PFAS, or synthetic flame retardants
• Is naturally breathable - regulating temperature and reducing moisture buildup during sleep
• Is biodegradable at end of life
• Is significantly gentler for sensitive skin, eczema-prone skin, and babies

A 2022 analysis by Textile Exchange found organic cotton has a 46% lower global warming potential than polyester, and uses substantially less water and energy to produce. But for most families, the more immediate reason to switch is simpler: you're probably spending a third of your life in it, and polyester is plastic.

The Bottom Line

The science on synthetic fibres is still developing. Researchers are careful to note that many studies are in vitro or animal-model-based, and large-scale human clinical trials on long-term polyester exposure are limited. That nuance is worth acknowledging.

But what we do know: microplastics from synthetic textiles are now found in human blood, placentas, lungs, and breast milk. The chemical additives in polyester include recognised endocrine disruptors. And bedding represents the longest, most sustained fabric-to-skin contact in any person's daily life.

You don't need to wait for a definitive verdict to make a simple, reasonable swap.

Waterproof. GOTS-certified organic cotton. Made for real families from bassinet to super king. Explore Milk&Bed Sheets →

References

• Jenner et al. (2022). Detection of microplastics in human blood. Environment International. PubMed
• Ragusa et al. (2021). Plasticenta: First evidence of microplastics in human placenta. Environment International. PubMed
• Ullah et al. (2023). Endocrine disrupting effects of micro and nano plastic in mammals. Frontiers in Endocrinology. PubMed
• Martínez-Pinna et al. (2023). Endocrine disruptors in plastics and diabetes risk. Am. J. Physiol. Endocrinol. Metab. PubMed
• Amato-Lourenço et al. (2021). Airborne microplastics in human lung tissue. Journal of Hazardous Materials. PubMed
• Napper & Thompson (2016). Release of synthetic microplastic fibres during washing. Marine Pollution Bulletin.
• Hatch & Maibach (1995). Textile fibre dermatitis. Contact Dermatitis. PubMed

This article is intended for educational purposes only and does not constitute medical advice. Consult a qualified health professional for personal medical guidance.