Why Your Underwear Matters More Than You Think

Why your underwear choice matters more than you think

Many people are not aware of this but most underwear you’ve worn throughout your life are most likely made of polyester. The issue with polyester and wearing this at your private parts is that it can affect your hormones in two ways: chemical leaching and temperature regulation. Although our skin is a protective barrier, it’s also porous.

Chemical Impact (Endocrine Disruptors)

Polyester isnt directly a ‘plastic’ but it is often made Endocrine Disrupting Chemicals (EDCs). One of the most common ones you’ve probably heard of on some labels are BPA and Phthalates, and mimic estrogen. In women, it could lead to irregular cycles, or endometriosis. In men, they can interfere with testosterone production.

Antimony:
Another heavy metal used as a catalyst is antimony, which leach out with sweat and linked to thyroid disruption.

PFAS (Forever Chemicals): Sometimes used for ‘performance’ or stan-resistant finishes, these are known for metabolism and reproductive health.

The Plastic Bag Effect

A common issue with polyester is that it doesnt breathe well, and creates for both men and women.

For men it’s the sperm production, and since the scrotum is located outside the body, they’re around 2 - 3 C lower than core body temperature. With trapped heat, it increases the temperature which reduces production. An interesting study, although old, discovered that 100% polyester underwear creates a small electrostatic charge due to friction, and it was linked to a drop in sperm count, which reversed when switching to cotton underwear.


For women the increased heat of such underwear creates a warm, damp environment, and may not lead to hormonal changes, but does increase yeast infections and more. If this continues and becomes chronic, it indirectly can affect cortisol-progesterone balance.


Active underwear and sports underwear:

While polyester is a global issue for underwear which we’ve still not caught up to in 2026, another hidden problem is found in gym wear. These are mostly made of high-tech plastics and chemical finishes.

The sweat problem:

A 2025 study from University of Birmingham revealed that oily components in human sweat act as a solvent. The sweat you produce does ‘leach’ toxic chemicals, such as BPA and phthalates, out of the synthetic fibers and makes your skin more vulnerable to these chemicals. Which is caused by your pores being open and blood flow which makes the endocrine disruption even worse.

How to protect your Endocrine Health

Time to go sustainable and try out underwear made from organic cotton, hemp, silk and bamboo. You can check for certifications, and buy OEKO TEX standard 100 or GOTS (Global Organic Textile Standard. It’s worth the investment and many times the prices are basically the same. You’re doing something good for yourself and the environment as well.