The Science Behind Organic Cotton & Why It's the Best Choice for Skin Health
Your skin is your body's largest organ. It protects you, responds to your environment and reflects your overall wellbeing, so what touches your skin matters. From everyday irritation to long-term skin concerns, your lingerie can either support your skin's natural balance or disrupt it. That's why more women are turning to organic cotton. In this guide, we explore the science behind organic cotton, why it's considered the gold standard for sensitive skin, what makes a good bra fabric, and the textile chemicals worth avoiding.
What is organic cotton?
Organic cotton is grown in a way that respects nature and has a minimal impact on the environment. It's produced without toxic pesticides, synthetic fertilisers or genetically modified seeds, and cultivated through eco-conscious methods that prioritise soil health, biodiversity and water conservation. Unlike conventional cotton, which relies on chemical-heavy farming, or synthetic fabrics that trap heat and irritate sensitive areas, organic cotton is breathable, hypoallergenic and naturally antibacterial. Think of organic cotton as skincare you can wear.
Skin-health benefits of organic cotton
It breathes with your body. Research confirms organic cotton's breathability, lowering the risk of rashes, overheating and trapped sweat. It helps prevent infections and odour, because its moisture-wicking ability reduces the damp conditions in which yeast and bacteria thrive. It softens over time rather than degrading like chemically treated cotton. It's naturally hypoallergenic: a 2020 study found choosing organic cotton can reduce the severity of dermatitis symptoms. And it supports your skin microbiome, which matters even more for reactive, hormonal skin.
“I have had severe allergic reactions to bras for the last 20 years and had been unsuccessful in my search until now. Finally, a bra I don't want to remove once I put it on.” (Theresa Z., United States)
What makes a good bra fabric (and which to be cautious with)
Four things decide how a fabric feels over a long day: breathability, moisture-wicking, softness and friction, and irritation risk. Organic cotton scores well on all four, and pure silk, a naturally hypoallergenic, antibacterial protein fibre, is smooth, light and cool, which is why JulieMay lines every bra cup and brief gusset in 100% pure silk. Be cautious with synthetic-heavy fabrics like polyester, nylon and elastane, which trap heat and can worsen eczema and psoriasis, and watch for exposed elastics, harsh dyes and nickel.
A note on formaldehyde and textile chemicals
Much of what irritates skin is added during manufacture. The most common example is formaldehyde, used as an anti-wrinkle finish, which can trigger contact dermatitis, and at high or prolonged exposure is classed by the US EPA as a probable human carcinogen. UK manufacturers are not required to disclose anti-wrinkle chemicals, so the simplest protection is to choose certified organic fabrics. JulieMay's lingerie is backed by a verified lab report confirming the 22 nastiest textile chemicals, including formaldehyde and harsh dyes, are not present.
For a side-by-side look at how organic cotton compares with bamboo and synthetics, see our guide to organic cotton vs bamboo vs synthetic.
What is organic Pima cotton, and why is it a big deal?
There is organic cotton, and then there is organic Pima cotton, the world's finest type of cotton, making up just 0.0005% of the world's total cotton supply. Along with pure silk, most of our bras, briefs and lingerie are made from certified organic Pima cotton, sourced from Peru.
The big deal is the extraordinary length of its fibres. While most cotton fibres are about half to three-quarters of an inch long, Pima cotton is around 1.375 inches, almost twice as long. This single property gives it incredible lustre and softness that rivals silk, naturally hypoallergenic properties, greater breathability and moisture absorption, and exceptional resistance to wrinkles, tears and fraying. It is often called the “cashmere of cotton”, and it is organically grown in the northern coastal valleys of Peru, free from toxic pesticides.
Organic cotton bralettes vs regular cotton bralettes
Organic Pima cotton is often handpicked, which avoids the fibre damage caused by the mechanical harvesting used for regular cotton, so it tends to be softer and more durable, with up to 50% more durability than regular cotton. Some brands like JulieMay back their products with verifiable laboratory reports confirming that none of the 22 nastiest dyes and chemicals went into making them, meeting strict standards including the Organic Content Standard (OCS), certified by Control Union.
How to choose the right bralette size
Bust size: measure around the fullest part of your bust, keeping the tape level. Band size: place the tape on your back, under your arms and across your chest just above the bust; if you get an odd number, round to the next even number. And the lovely thing about a bralette is that you don't have to hide it, from backless dresses to looser styles where a structured bra doesn't work.
Organic cotton bra and knicker features
Our skin-friendly organic cotton bras are the best everyday option for sensitive skin. JulieMay is the only underwear brand accredited by Allergy UK as friendly for people with allergic reactions to synthetic fibres. Every bra pairs breathable organic cotton with a pure silk lining and cotton-wrapped bands, so there are no exposed elastics, no nickel and no harsh dyes. Our cotton knickers use the same GOTS-certified organic Pima cotton, naturally antibacterial and breathable, finished with delicate lace, because comfort and beauty don't have to be a compromise.
Frequently asked questions
Why is organic cotton better for sensitive skin?
It's grown without pesticides or harsh chemicals and is naturally breathable, hypoallergenic and antibacterial, so it's far less likely to trigger irritation, rashes or allergic reactions than synthetics or chemically treated cotton.
What is organic Pima cotton, and why is it special?
Pima is an extra-long-staple cotton (around 1.375 inches, versus half to three-quarters of an inch for ordinary cotton). The longer fibre makes it softer, stronger, more lustrous and less prone to pilling; organic Pima is just 0.0005% of global cotton supply.
Is formaldehyde in clothing dangerous?
For most people levels are low, but it can trigger contact dermatitis in those who are sensitive and at high or prolonged exposure is classed as a probable carcinogen; choosing certified organic fabrics avoids it.
Is organic cotton better for the environment?
Yes; it uses around 91% less water than conventional cotton, avoids synthetic pesticides and fertilisers, and is biodegradable, so it doesn't shed microplastics like synthetic fabrics.
Related reading
- Organic Cotton vs Bamboo vs Synthetic: Which Is Best for Sensitive Skin?
- What Is The Best Material for Your Bra?
- Contact Dermatitis From Clothing: Signs & Fabric Considerations
Educational content only; not a substitute for professional medical advice.
