Girl, Your Underwear Matters More Than You Think

We research our skincare. We read labels on our food. We ask questions about what goes into our bodies.

But underwear? Most of us grab whatever’s cute, on sale, or in a multipack, and never think about it again.

Here’s the thing, sis: your underwear sits against some of the most sensitive skin on your body for hours a day. What it’s made of, how it fits, and even how you wash it can make a real difference in your comfort and your vaginal health. Let’s break down what the experts actually say.

Why your underwear matters

Your vulva and vagina have their own balance of moisture, pH and healthy bacteria. Underwear can help that balance, or work against it, in a few simple ways.

Heat and moisture. Yeast thrives when it’s warm and damp, so fabrics that trap warmth and moisture can make irritation and infections more likely.²

Airflow. Cotton lets air circulate around the vagina, which is why it’s the fabric OB-GYNs recommend most.¹²

Irritation. Synthetic fabrics, dyes and even detergent residue can irritate vulvar skin.¹

“[Cotton] is less likely to cause an allergic reaction than synthetic fabrics.”

Erica Newlin, MD, OB-GYN, Cleveland Clinic¹

Fabric: why cotton wins

Nylon, polyester and spandex blends can feel silky, but they don’t breathe like cotton. Health guidance warns that nylon underwear, tights and leggings without a cotton lining trap warmth and moisture.²

Cotton does the opposite. It wicks away sweat and moisture, which bacteria and yeast thrive on.¹

Is a cotton gusset enough?

Many synthetic styles add a small cotton panel in the crotch. It’s better than nothing, but Cleveland Clinic OB-GYN Dr. Erica Newlin says it’s not the full answer.¹

“That small panel doesn’t fully protect you from the synthetic fabric.”

Erica Newlin, MD¹

One survey study points the same way: wearing underwear without a cotton crotch was linked to yeast infections.³

Read the label

Some underwear feels like cotton but is mostly synthetic. Check the fiber content, and if your skin is very sensitive, Cleveland Clinic suggests plain white cotton, since dyes can irritate sensitive skin.¹

What the research can’t tell us yet

To be honest with you: studies on underwear and vaginal health are limited, and most look at habits people report rather than controlled trials.³ So think of cotton as a smart, low-risk everyday choice that doctors recommend, not a cure for anything.

What’s hiding in the fabric

Fiber is only half the story. Underwear also goes through dyeing and finishing, and some of those chemicals stay in the fabric.

Formaldehyde finishes

Formaldehyde resins are used on some textiles, for example to resist wrinkles. When the U.S. Government Accountability Office (GAO) studied the issue, it found the main health concern from clothing is allergic contact dermatitis: rashes, blisters, and dry, itchy or burning skin.⁴

The good news: in GAO’s testing of 180 items, most were below the strictest limits used elsewhere, and levels have dropped since the 1980s.⁴ The catch: the U.S. doesn’t regulate formaldehyde in clothing at all, while the industry reports that 13 other countries do.⁴

PFAS in some period underwear

PFAS, often called “forever chemicals,” are used to make products water-resistant. They don’t break down naturally, and some types have been linked to health problems including certain cancers and hormone disruption.⁵

In 2020, independent testing by a Notre Dame physicist found high levels of fluorine, a marker of PFAS, in the crotch of Thinx organic period briefs.⁵ Customers sued, and in January 2023 Thinx agreed to pay up to $5 million and to help ensure PFAS aren’t intentionally added, without admitting wrongdoing.⁵

That doesn’t mean every period or leak-proof brand uses PFAS. It does mean “organic” on a label isn’t the whole story, so it’s worth asking brands how their absorbent layers are made.

How certifications help

This is where third-party certification matters. The Global Organic Textile Standard (GOTS) covers more than the cotton itself. It bans chemicals known to cause cancer or reproductive harm, including formaldehyde, and prohibits chemical groups such as azo dyes and PFAS.⁶ Certified companies are inspected every year, and products are tested based on risk.⁶

That’s why every Puure piece is made with GOTS-certified organic cotton and third-party tested. Our goal is simple:

“The layer closest to your body should be the cleanest one you own.”

Puure

Fit and habits that make a difference

Washing matters too

• Use a fragrance-free, dye-free detergent. Many detergents leave residue that can irritate the vulva.¹
• Wash new underwear before wearing it to remove chemicals from manufacturing and handling.¹
• Consider an extra rinse if you’re sensitive.¹
• Skip scented products down there, like sprays and scented pads, tampons or toilet paper.²

When it’s not your underwear

Better underwear can make you more comfortable, but it can’t diagnose or treat anything. Some symptoms need a provider, not a new pair of panties.

“I’d suggest something looser and more breathable.”

Erica Newlin, MD, on underwear for recurring irritation¹

And one more myth to retire: your vagina cleans itself. Douching is rarely needed, so skip it unless your provider tells you otherwise.²