Polyester and Fertility: What's the Truth About the Hormone Risk?
Polyester is found in more than every second fiber worldwide, and at the same time, hormonal problems such as PCOS and endometriosis are increasing. This article classifies the research, explains the discussed mechanisms of action via microplastics and electrostatic fields, and shows what you can do in your everyday life without panicking.
Key takeaways
Polyester accounts for over 50% of global fiber production, while hormonal disorders such as PCOS and endometriosis are on the rise. Two mechanisms of action are discussed: chemical, via microplastics and accompanying substances such as BPA, phthalates, and PFAS, and physical, via electrostatic fields. The evidence comes primarily from animal studies and experiments with extreme long-term exposure; direct proof in humans is lacking. Not abstinence, but conscious handling is sensible: natural fibers in intimate areas, microfiber filters when washing, balanced diet.
Polyester is now found in more than half of all fibers worldwide, from sports shirts and leggings to underwear. At the same time, hormonal problems such as PCOS, endometriosis, and thyroid disorders are on the rise. Is there a connection? This article categorizes the research, explains how synthetic fibers could have an effect via microplastics and electrostatic fields, and shows what you can do.
Polyester and hormones: why a connection is being discussed at all
Since the mid-20th century, polyester production has exploded, from around 5 million tons in 1980 to over 71 million tons in 2023. In the same period, hormonal diseases in women have accumulated. Environmental medicine specialists see possible connections to so-called endocrine disruptors, i.e. substances that can disrupt the hormone system.
Important for classification: a temporal parallel does not prove a cause. Many factors play a role, from genetics to lifestyle and environment. What research provides are mechanisms and correlations that are worth taking seriously, without resorting to scaremongering.
Did you know that …
… a single fleece garment can release over 1,900 microfibers per wash cycle? These microplastic fibers have now been detected in blood, placenta and even testicular tissue. A 2022 study found microplastic particles in the blood of almost 80% of the people examined.
Where on the body polyester could be critical
Whether polyester is problematic depends less on the material alone than on how and where it is worn: how tight, how long and on which body zone. The following overview categorizes the most important risk zones.
Most important zone, direct contact with testes or ovarian region. Natural fibers recommended.
Abdomen and waist (shapewear, high-waist)
Tight fit over the ovarian region, static charge.
Not directly proven in humans, hypothesis derived from animal data.
Chest and armpit (sports bra, tight shirts)
Sweat, odor, possible PFAS coatings.
Hormonally secondary, additional chemicals are more relevant than the fiber itself.
Feet and extremities (socks, compression)
Sweating, fungi, large skin contact area.
No direct fertility relevance, but microfiber abrasion throughout the day.
It's not about banning polyester completely. It's about making conscious choices, especially where fabric lies directly on the skin for hours.
Did you know that...
... a single fleece garment can release over 1,900 microfibres per wash cycle? These microplastic fibres have now been detected in blood, placenta, and even testicular tissue. A 2022 study found microplastic particles in the blood of nearly 80% of the people examined.
From wonder material to all-purpose fibre: the history of polyester
Polyester was patented as early as 1928, but it only really took off after the Second World War. In 1951, DuPont introduced the fibre "Dacron" in the USA, promising wrinkle-free, easy-care clothing. In the "Wash-and-Wear" movement of the 1950s and 60s, polyester was considered a miracle fibre. After a slump in its image in the 70s, the 80s saw a comeback with finer microfibres and functional textiles, and from the 2000s onwards, fast fashion made polyester ubiquitous.
Production rose rapidly: from around 5.2 million tonnes in 1980 to 19 million tonnes in 2000 and over 71 million tonnes in 2023. Around the turn of the millennium, polyester overtook cotton. Today, more than one in two textile fibres is made of polyester.
The parallel increase in hormonal disorders
In the same period in which plastics have permeated our daily lives, hormonal disorders in women appear to be increasing. The causes of such conditions are diverse, ranging from genetics to lifestyle and environment. A growing number of studies are focusing on so-called endocrine disruptors, i.e. substances that can interfere with the hormone system. Important: These observations are correlations, not proof of cause and effect.
PCOS and BPA: In polycystic ovary syndrome (6 to 12% of women of reproductive age), higher bisphenol A levels have been measured in the blood. BPA has estrogen-like effects. It is suspected that chronic exposure can contribute to hormonal imbalance.
Endometriosis and phthalates: Several studies suggest a link between phthalate exposure (plasticisers) and the risk of endometriosis. In animal experiments, exposed mice developed more endometriosis-like lesions.
Thyroid and PFAS: Per- and polyfluorinated substances (PFAS), some of which are used as coatings in functional textiles, are considered endocrine disruptors that could impair thyroid function.
Male fertility: The average sperm count has decreased in many countries over decades. Smoking, diet and stress play a role, but environmental chemicals from plastics are coming into focus.
These substances do not come directly from the polyester fibre itself, but polyester products are part of the plastic environment that spreads such substances. The temporal parallel provides the background against which we consider polyester clothing as a possible component of this exposure, nothing more and nothing less.
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Two mechanisms of action are being discussed: chemical and physical. Both are not conclusively proven, but they provide plausible mechanisms that are being further investigated.
Chemical factors: microplastics and additives
If microplastic fibers enter the tissue, the body recognizes them as foreign bodies. Animal studies suggest that microplastics can cause inflammation and cell damage there. In addition, microplastics can act as a carrier for other pollutants: environmental toxins attach themselves to the particles and are released again in the body. The fiber itself is largely inert, but accompanying chemicals such as plasticizers, BPA or PFAS are more problematic, as they can dock onto hormone receptors and disrupt hormonal balance. In studies of sportswear, traces of fluorine were found in some of the tested leggings and yoga pants, indicating PFAS.
Physical factors: electrostatic fields and heat
Polyester becomes electrostatically charged through friction, natural fibers hardly do. In the 1990s, physician Ahmed Shafik investigated whether an electrostatic field near the testicles impairs sperm formation. In his experiments, men wore a polyester scrotal sling continuously for long periods and developed reversible azoospermia, which normalized after removal of the material. Hormone levels and body temperature remained largely unchanged, supporting the hypothesis of an electrostatic effect. Supplementary animal studies on male and female dogs showed similar, reversible effects on sperm quality and ovulation, respectively.
These findings need to be put into perspective: these are predominantly animal studies and experiments with extreme continuous exposure over months to years. In everyday life, no one wears the same garment continuously. Direct evidence that normal polyester clothing causes infertility in humans is lacking. However, it is plausible that cumulative effects could occur, especially in combination with heat, tight fit and chemical exposure.
How you can protect yourself specifically
It's not about abstinence, but about informed decisions, especially for people who want to have children or have existing hormonal problems. These measures reduce exposure and are also good for the environment.
Shop consciously
Underwear made from natural fibers:Cotton, bamboo viscose or hemp reduce heat build-up and do not become electrostatically charged. This is the most important adjustment screw, especially in the intimate area.
Choose blended fabrics:Even a 50:50 cotton content halves the electrostatic effect compared to pure polyester in studies.
Look for seals:Oeko-Tex 100 stands for tested low pollutant content, GOTS for predominantly organic natural fibers. Prefer PFAS-free outdoor and sportswear.
Wash and care correctly
Wash less often and cooler:Air instead of washing reduces fiber abrasion, 30 degrees on a gentle cycle also protects the fibers.
Use microfiber filters:Washing bags like Guppyfriend or retrofittable machine filters trap a large proportion of microfibers before they enter the wastewater.
Omit fabric softener:It deposits surfactants and fragrances in the fiber, which then get onto the skin.
Reduce microplastics in the household
Microplastics return to us via house dust and the environment. Regular vacuuming with a HEPA filter and damp wiping binds particles, good ventilation when drying helps, and you should store food better in glass or stainless steel instead of plastic. Do not heat plastic containers, as heat promotes the release of components.
Diet as support
A high-fiber diet with vegetables, flaxseed and psyllium husks can support excretion via the intestines. Antioxidants from fruits, vegetables and spices such as turmeric help against oxidative stress. Sufficient filtered water supports the kidneys and liver. Detox promises via activated carbon, zeolite or algae are not scientifically clearly proven; the actual detoxification is carried out by the liver, kidneys and intestines.
Polyester is practical and ubiquitous, yet its potential downsides deserve attention. The available data shows plausible mechanisms regarding microplastics, accompanying chemicals, and electrostatic fields, but relies heavily on animal studies and experiments with extreme long-term exposure. Direct evidence for infertility caused by normal clothing is lacking.
Therefore, a complete renunciation is not sensible, but rather a conscious approach: natural fibers where fabric lies directly on the skin for long periods, microfiber filters when washing, and a balanced diet. If you are trying to conceive or have hormonal problems and want to make your daily life more hormone-friendly, the medical team at Hormonic Care will support you.
Frequently Asked Questions about Polyester and Fertility
Does polyester cause infertility?
Direct proof of this is lacking. Studies showing an effect predominantly originate from animal experiments or investigations involving extreme prolonged exposure, such as wearing a polyester scrotal sling continuously for over a year. Moreover, these effects were reversible. In everyday life, nobody wears the same garment continuously. It is plausible that polyester, in combination with heat, a tight fit, and chemical exposure, could be a contributing factor; the current data does not allow for more definitive statements.
Is polyester underwear harmful?
In the intimate area, natural fibers are the better choice. Polyester underwear dissipates heat less effectively, creates a warm, moist environment, and builds up static electricity. This can lead to skin irritations and, in women, increase the risk of vaginal yeast infections. Breathable cotton is recommended for those trying to conceive. There is no proven direct damage to human fertility, the precautionary recommendation is based on plausibility and animal data.
What do microplastics in clothing have to do with hormones?
When synthetic clothing is washed, microfibers are released. These microfibers, categorized as microplastics, have been detected in blood, placenta, and even testicular tissue. The fiber itself is largely inert; more problematic are accompanying chemicals like plasticizers, BPA, or PFAS, which can bind to hormone receptors and thus disrupt hormonal balance. Animal studies also indicate inflammation in tissues due to microplastics. While direct proof of hormonal damage in humans is still pending, the existing evidence is sufficient to consciously reduce exposure.
What clothing is recommended when trying to conceive?
In the intimate area, breathable natural fibers such as cotton are the best choice because they dissipate heat and do not become electrostatically charged. For men who wish to have children, loose cotton boxer shorts are recommended instead of tight polyester briefs, and for women, cotton underwear and, if possible, natural fiber-based clothing for the lower abdomen. Blended fabrics with a high cotton content already significantly reduce the electrostatic effect. These are precautionary measures based on plausibility and animal data, not an indication of proven harm.
How do I wash polyester with minimal microplastic release?
Wash polyester less often and at cooler temperatures, ideally at 30 degrees on a delicate cycle, as heat and vigorous spinning increase fiber abrasion. Use a microfiber washing bag like Guppyfriend or a retrofittable machine filter, which catch a large proportion of the fibers. Avoid fabric softener and air out clothes more often instead of washing them immediately. This way, less microplastic ends up in the wastewater and on your skin, and textiles last longer.
Scientific Sources
Textile World (2015). Man-Made Fibers Continue To Grow. Global fiber demand and polyester production.
GoodMakerTales (2023). Does polyester underwear cause infertility? Summary of studies by Prof. Ahmed Shafik.
Shafik A et al. (1993). Effect of polyester underwear on the canine sperm picture, reversible after withdrawal. PubMed 8279095.
Shafik A (2008). Polyester textile and ovulation in the bitch, reversible after removal. PubMed 18393023.
AAMC, Balch B (2024). Microplastics are inside us all, detection in human organs and correlation with low male fertility.
Hindustan Times (2025). Frequent use of plastic impacts female fertility, EDCs, BPA and phthalates in connection with PCOS and endometriosis.
The Guardian (2014). Inside the fight against microfibers, around 1,900 fibers per wash cycle, microfibers as a large proportion of coastal litter.
Sustainable Fashion Forum (2018 to 2020). Polyester accounts for around 52% of global fiber production.
Market Analysis Women's Activewear (2023). Polyester as the most used material in the activewear segment.
Selbst-management.biz (2025). Microplastics, danger and reduction, tips on natural fibers, filters and nutrition.
About the Author
Lisa Maria Emmer
Medical Director · Hormonic
Lisa Maria Emmer is co-founder and medical director at Hormonic. She supports women with hormonal problems every day and specializes in cycle health, PCOS, and menopause.
Please note: This article is based on current scientific studies, reviews, and reports and has been compiled with the utmost care. It is for informational purposes only and does not replace medical advice, diagnosis, or treatment. Mentioned dietary supplements are not a substitute for a balanced diet and a healthy lifestyle. If you have existing medical conditions, are pregnant or breastfeeding, or are taking medication, always consult a doctor before taking any dietary supplements.
