Are Your Leggings Messing with Your Hormones?
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The hidden toxins in activewear you need to know about
Leggings have become a wardrobe staple for women everywhere. Comfortable, flattering, and perfect for everything from workouts to lounging, it’s no surprise that leggings are a go-to garment. But have you ever considered what your leggings are made from – and how those materials might be affecting your health?
Unfortunately, many leggings are made from synthetic fabrics derived from petrochemicals, containing plastic fibres and a cocktail of chemical additives.
When worn for extended periods, especially during exercise when the body is sweating and absorbing more, these chemicals can pose a hidden risk to your health.
Find out what chemicals could be lurking in your leggings, how they may be affecting your health, and safer alternatives to choose.
What’s in your leggings?
Most conventional leggings are made from blends of synthetic fibres such as polyester, nylon and elastane (Spandex or Lycra). While these fibres offer stretch, durability and sweat-wicking properties, they also bring with them a cocktail of chemicals including:
Microplastics: These tiny plastic fibres shed during wear and washing, polluting waterways and harming marine life. They can enter the human body via skin contact, inhalation or ingestion, triggering inflammation, hormone disruption, oxidative stress, and long-term health effects as they accumulate in tissues such as the brain.
Phthalates: Often used to soften plastics and improve fabric flexibility, phthalates are known endocrine disruptors that may interfere with hormone balance, fertility, and foetal development.
PFAS (per- and polyfluoroalkyl substances): These “forever chemicals” are added for water, oil or stain-resistance. PFAS accumulate in the body and have been linked to immune suppression, thyroid dysfunction, reproductive harm and cancer.
Formaldehyde: Used to reduce wrinkles and prevent shrinkage, formaldehyde is a known skin irritant and classified as a human carcinogen by health authorities.
Azo dyes: Commonly used to colour synthetic fabrics, some azo dyes can break down into aromatic amines which are compounds associated with an increased risk of cancer.
Because leggings are tight-fitting and worn directly against the skin – often in the warm, damp environment of a workout – they can increase chemical absorption through the skin. For women, this can be particularly concerning when leggings are in close contact with sensitive areas, potentially disrupting the vaginal microbiome or affecting hormone regulation over time.
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The health impact of wearing leggings
The endocrine system is finely tuned, and even small exposures to hormone-disrupting chemicals can have a significant effect over time. Here are some potential impacts from the toxins found in leggings:
Hormonal imbalances: Exposure to chemicals like phthalates, BPA and PFAS can mimic or block hormone signalling. This can contribute to PMS, fertility issues, early puberty, thyroid disruption, or even hormone-related cancers over time.
Skin irritation and dermatitis: Chemical residues such as formaldehyde, azo dyes and synthetic fragrances can lead to itching, rashes or allergic reactions – especially when combined with sweat and friction.
Increased toxic load: The skin is not only a detox organ but also highly absorptive. Daily exposure to synthetic fibres and chemical finishes can increase the body’s toxic burden, potentially impacting immune function, liver detox pathways and overall vitality.
Disruption of microbiome balance: Some chemical treatments in clothing, such as antimicrobial finishes, disrupt the skin’s natural microbiome, which plays a key role in immunity, inflammation and skin health.
Respiratory or neurological effects (in manufacturing exposure): Factory workers exposed to these chemicals during production may face serious health risks, raising ethical concerns about the broader impact of these materials.
What are the alternatives?
The good news is that more sustainable, non-toxic activewear options are available. Here’s what to look for when choosing safer leggings:
Natural or organic fibres
Choose leggings made from natural fibres like organic cotton, bamboo viscose (closed-loop process) and hemp. These materials are breathable, biodegradable and processed without toxic chemicals, making them safer for your skin and the environment.
OEKO-TEX® or GOTS certified fabrics
Look for certifications that ensure the garment has been tested for harmful substances. OEKO-TEX® Standard 100 and GOTS (Global Organic Textile Standard) are two trusted certifications for non-toxic, ethically made fabrics.
Low-impact dyes and chemical-free finishes
Some brands are now dyeing their fabrics with plant-based or low-toxicity dyes, such as those derived from indigo, turmeric, madder root or beetroot. These natural dyes are often combined with non-toxic mordants like tannins to help set the colour, avoiding the use of heavy metals or harsh synthetic chemicals. Brands are also steering clear of chemical finishes like wrinkle-resistant or anti-odour coatings that typically contain formaldehyde.
Sustainable brands that disclose ingredients
Choose brands that are transparent about their supply chains, materials and manufacturing practices. Companies like People Tree, Thought Clothing, BAM Bamboo Clothing, Pure Woven and Komodo are all strong choices, known for their commitment to sustainability, fair trade, and the use of natural or organic fibres.
Make safer, ethical choices
While leggings may seem like a simple fashion choice, they can carry hidden health and environmental costs. As consumers, being informed about what we wear – especially in clothing that sits close to the skin – is vital for long-term well-being.
By switching to non-toxic, natural-fibre leggings and supporting brands that prioritise safety and sustainability, you can protect your health and reduce your exposure to hormone-disrupting chemicals. Your skin (and your hormones) will thank you.
To learn more about environmental toxins, detoxication and ways to support your health naturally, take a look at the following short courses and resources:
