Looking at my underwear drawer, I yearn for a simpler time. I remember fondly my first bralettes – essentially two cotton triangles stitched together with a supportive band. Knickers were basic, too: cotton briefs in a choice of three different cuts.
But undies somehow became incredibly complex. Today, bras aren’t just bras, they’re ‘posture facilitators’; knickers are sold with promises of moisture management, breathability, temperature regulation and leak control. And I am bombarded by a hundred types of shapewear garments guaranteeing everything from supporting my back muscles to firming my thighs. In fact, the shapewear market is predicted to rise by 37 per cent between 2024 and 2028. I’m all for progress but, really, who wants to be outwitted by their ‘intelligent fibre’ pants?
Especially when much of this isn’t just facilitated by clever design but by chemicals, additives and synthetic fibres. Last year, bras and pants hit the headlines when consumer associations in several countries undertook laboratory tests on 166 types of underwear. The study revealed extraordinary levels of contamination, with researchers concluding that one in three underwear products contains toxic chemicals and one in ten has harmful levels. The toxins detected were bisphenols, a class of chemicals used to make plastics tough and temperature-resistant.
Even at very low levels they can act as endocrine disruptors, meaning they can block or interfere with hormones, potentially causing a range of chronic health disorders. They’ve been linked to hormone-related cancers, diabetes, reproductive and cardiovascular diseases, allergies, neurodevelopmental issues and foetal and developmental disorders.
Bisphenol A (BPA) was once common in all manner of plastic goods, from kitchen utensils to baby bottles, but it was deemed so harmful it was banned from anything that would come into contact with food or beverages. Yet bisphenols are still showing up in underwear, and some manufacturers have shifted to similar chemicals in the same group – bisphenols S and F. These are routinely used in substances that make synthetics such as Lycra (also known as spandex and elastane) colour-fast, which is why they’re detected in our underwear.
A new documentary film, Let Them Be Naked, due out in September, tackles the issue. It is produced by Suzy Amis Cameron, a long-time environmental campaigner and the wife of Titanic director James Cameron. She has described the mix of toxic chemicals in clothing as a ‘public health issue that must be addressed’.
For the film’s star and director, sustainable fashion designer Jeff Garner, this is personal – he lost his own mother to breast cancer in 2019. The film takes a close look at links between bras and breast cancer, following the trail begun by the Californian non-profit Center for Environmental Health, which found levels of BPA in sports bras up to 22 times the state’s legal safe limit (in the UK there is currently no limit).
Watching the documentary may have you itching to whip off your bra immediately, but it’s not as easy as that. Like many women in the UK, where the average chest size is now 36DD, I can’t contemplate life sans bra.
I need support, but those that offer the best (such as sports bras) are among the worst offenders of toxic overload. Most are made from petroleum-based plastic fibre, including a pick-and-mix of chemical additives that give the fabrics different qualities. It’s not uncommon to be offered ‘benefits’ including moisture wicking (drawing moisture to the outer side of the garment), breathability, smoothing and no-slip straps.
Researchers have found per- and poly fluoroalkyl substances (PFAs), known as ‘forever’ chemicals (because they exist indefinitely), added to our undies to make them flame retardant. Forever chemicals are linked to nasty health effects, including thyroid disease and hormone disruption. Quite why we need flame-retardant bras isn’t clear, but forever chemicals’ presence was found in another study, from the University of Birmingham in 2023, which revealed how sweat draws out these fire-resisting-chemicals from sports bras, leaching them into our bodies.
Studies are also beginning to look more closely at how our bodies might absorb different substances, at what rates and in what concentrations. A 2023 study focusing on underwear made in China detected high migration rates (between 21 and 100 per cent) of copper, arsenic, nickel and cadmium from bras and knickers tested. It is too early to say what the effects might be – and this is only a small study that won’t apply to every bra or pair of pants, but the researchers make the point that, as the vagina is highly absorbent, these findings shouldn’t be overlooked. After all, we know that women exposed to high levels of heavy metals have been shown to experience potential harm to their reproductive systems, even infertility. In older women, exposure to toxic metals has been linked to accelerated ovarian ageing.
Can this brewing public-health issue be diverted from becoming a crisis? A sense of righteous anger towards the companies that produce underwear and athleisure wear is understandable, but some brands are moving to reassure consumers.
M&S was the UK’s first major retailer to launch a chemical compliance policy, back in 1998, and it is continually updated. A spokesperson tells me, ‘We do not use PFA chemicals in the manufacturing and finishing of any of our clothing products, including underwear. We are committed to the responsible management of chemicals used in the manufacture of our products, and all suppliers must comply with the M&S Restricted Chemical Policy.’
But not all brands have the same standards, and we are seeing a rapid expansion of this highly profitable part of the fashion industry. By 2030 the ‘intimate apparel’ sector is projected to be worth £75 billion. To grow in an increasingly crowded space there’s no doubt the industry will continue to push consumers towards synthetic apparel with technical features.
But these ‘breakthroughs’ are achieved by introducing chemical additives to plastics and marketing them to us at increasing velocity.
While the existence of chemicals in our underwear is concerning, don’t panic. Studies so far have been relatively small and there is no definitive link between different types of toxic chemicals, concentrations or illness. In truth, we are exposed to potentially hazardous chemicals at every turn in life (a 2024 study showed that consumer goods, from toys to computers, rely on the use of more than 16,000 different chemical additives, and a quarter of these are deemed potentially hazardous to human health). However, exposure to them doesn’t mean you’re going to get ill and some health experts point out that the human body excels at removing toxins.
So, what to do? Toxicologists have a favourite saying: ‘the dose makes the poison’, meaning it is the quantity that determines the risk. While eradicating exposure is nigh on impossible in the modern world, you can lower it, and it is never too late to take back control – starting with your knicker drawer.
Six steps to detoxing your delicates
1 Buy simple cotton briefs
Forget engineered items that promise to mould, wick, shape, tone and control odour; just go for cotton. I love styles by thunderpants.co.uk, greenfibres.com and bynature.co.uk. Stripe & Stare pants (£18, right) can be delivered via Ocado. For shapewear, also try Intimissi’s cotton shorts.
2 Embrace white undies
Dark fabrics contain higher levels of bisphenols from the dyeing process. But don’t try to keep underwear super-white: bleaching agents can introduce other potential toxins.
3 Ditch your sports bra ASAP
Limit your exposure to toxic chemicals by taking off your sports bra as soon as you finish your workout. A non-toxic option is Allbirds Woman’s Performance Sports Bra with removable pads (£55, allbirds.co.uk).
4 Avoid moulded cups
Bras with a smooth look have higher chemical loads, as foam is often treated with fire-retardant ‘forever chemicals’. ‘Embrace the nipple’ or try Emilia’s organic padded bra (£66, etsy.com).
5 Think natural
Look for cotton, hemp, silk and modal bras, as well as natural options for sweat control. Wool and plant-based fibres move sweat away from the core without the chemical burden. Try Modibodi’s Merino Active bra (£52.99, modibodi.co.uk, right).
6 Wash new undies before wearing
Some studies show certain bisphenols can be removed by laundering, although others have revealed that chemicals can move to another part of the item.
