Almost every list of vulva care tips says to wear cotton underwear, and most people follow it without knowing why. There's good reason behind it, but the research is more nuanced than the advice, and fabric isn't the only thing that matters. How tight the underwear is, how it's washed and how long you wear it all count, because the skin of the vulva behaves differently from the skin on your arms or back.
This article compares the common fabrics, looks at what the studies found about style and fit, and covers the washing habits that can undo the benefit of a good fabric.
In this article
- Why fabric matters on this skin
- Cotton
- Nylon, polyester and other synthetics
- Silk, bamboo and the rest
- The fabrics compared
- Thongs, fit and tightness
- How you wash it matters too
- When underwear isn't the answer
- Frequently asked questions
Why fabric matters on this skin
The vulva spends most of the day warm, covered and pressed against fabric. Whatever touches it stays in contact for hours, and sweat and discharge have nowhere quick to go.
Cleveland Clinic lists underwear made of synthetic materials, like nylon, among the irritants that can trigger vulvar dermatitis, an irritated, itchy vulva. It also notes that symptoms can flare when you're hot or sweating.
So the job of underwear down there is fairly simple: sit gently, let some air through, handle moisture, and not add anything that irritates. Different fabrics do those jobs differently.
Cotton
Cotton is the fabric clinicians recommend most. The NHS advice for people prone to thrush is to wear cotton underwear and avoid tight underwear or tights. Cleveland Clinic's advice for an itchy, irritated vulva is cotton underwear, or none at all, instead of synthetic fabrics. An NHS vulva care leaflet says the same thing in fewer words: loose fitting cotton underwear.
There's some research behind the habit. In a survey of nearly 1,000 women, wearing underwear with a non-cotton crotch was associated with yeast infections, while the style of underwear wasn't linked with any infection. A survey can show a link, not a cause, but it points the same way as the clinical advice.
Cotton has its limits. It soaks up sweat and can feel damp after a long, hot day or a workout. For exercise, our article on vulva chafing covers what tends to work better.
What to look for in cotton underwear
The part that touches the vulva matters most. A lot of underwear is made of a synthetic blend with only a cotton gusset, the small panel in the crotch. If you're choosing for comfort down there, check that the gusset is cotton, and prefer a plain, soft weave without lace or heavy seams in that area.
Nylon, polyester and other synthetics
Synthetic fabrics are smooth, stretchy, quick to dry and good at holding their shape. They're why shapewear, seamless underwear and most sports underwear exist.
The trade-off is that many people find them warmer against the skin. Cleveland Clinic names synthetic underwear such as nylon as a possible irritant for vulvar dermatitis, and the survey above linked a non-cotton crotch with yeast infections.
That doesn't make synthetics off limits. Plenty of people wear them every day without trouble. If your skin is easily irritated, or you get infections often, a cotton gusset is the simplest change to try first, and wearing synthetics for shorter stretches, like a workout, rather than all day and night is another.
Silk, bamboo and the rest
Silk has one small, interesting trial behind it. Twenty women with a long-lasting itchy vulvar skin condition were treated with a steroid ointment, then randomly given silk or cotton briefs for four weeks. The women wearing silk went longer without needing the ointment again, about 22 days compared with about 7. The study was tiny and used a specific medical-grade silk, so it doesn't prove silk is better for everyone, but it suggests smooth, non-irritating fabric can matter for skin that's already sensitive.
Bamboo and modal are soft fabrics made from processed plant fibres. We found no good research on them for vulvar skin. Many people find them comfortable, and they're a reasonable choice if they feel good and your skin stays calm.
Merino wool is popular for hiking and sport. Again, there's no vulva-specific research. Some people find wool itchy, which is the opposite of what you want here.
Cotton has the most clinical advice behind it, and silk is worth a try if your skin is easily irritated. For the other fabrics, the best guide we can offer is how your own skin feels after a few weeks of wearing them.
The fabrics compared
| Fabric | How it feels and behaves | What the evidence says | Good for |
|---|---|---|---|
| Cotton | Soft, breathable, holds moisture | Recommended by the NHS and Cleveland Clinic; a non-cotton crotch was linked with yeast infections in one survey | Everyday wear, sleep, sensitive skin |
| Nylon, polyester, spandex blends | Smooth, stretchy, dries fast, can feel warm | Named by Cleveland Clinic as a possible irritant | Short stretches, sport, special outfits |
| Silk | Smooth, light, low friction | One small trial in women with a vulvar skin condition favoured silk over cotton | Skin that's easily irritated |
| Bamboo or modal | Very soft, drapes well | No vulva-specific research found | Everyday wear, if your skin stays calm |
| Merino wool | Warm, popular for sport, can feel scratchy | No vulva-specific research found | Hiking and sport, if it doesn't itch |
Thongs, fit and tightness
Thongs get blamed for a lot, but the survey of nearly 1,000 women found thong use wasn't linked with urinary tract infections, yeast infections or bacterial vaginosis. The authors' advice to clinicians was to talk about underwear fabric rather than style.
Tightness is a different matter. The NHS advises against tight underwear and tights for people prone to thrush, and anything tight increases rubbing, which irritated skin doesn't need. Leggings, shapewear and tight jeans over underwear add to that.
A few habits help regardless of what you wear:
- Change out of damp underwear, from sweat or swimming, as soon as you can.
- Give your skin time without underwear, overnight for example. Cleveland Clinic lists going without as an option for an irritated vulva.
- Choose a size that doesn't dig in at the leg openings or the waist.
- Keep tight, synthetic pieces for the times you want them rather than every day.
If shaving or waxing is part of your routine, tight underwear right after hair removal can rub freshly treated skin. Our article on razor bumps on the bikini line explains why that matters.
How you wash it matters too
A good fabric can still irritate if it carries something from the wash. The NHS vulva care leaflet suggests washing underwear with non-biological detergent or plain water and notes that fabric conditioner contains possible skin irritants.
In practice, that looks like this:
- Use a detergent without fragrance, and the smallest amount that gets clothes clean.
- Skip fabric softener and dryer sheets for underwear.
- Rinse well, or add an extra rinse cycle if your skin is sensitive.
- Wash new underwear before wearing it the first time.
If you've changed your soap and your underwear and the irritation keeps coming back, laundry products are worth a look. Our vulva care routine covers the rest of the daily basics.
When underwear isn't the answer
Changing fabric helps with irritation from rubbing, heat and moisture. It won't fix an infection or a skin condition, and it's worth seeing someone if:
- itch or soreness lasts more than a week or two after you've changed fabric and laundry products
- your discharge changes in colour, smell or texture
- you have sores, splits or skin that turns white, thin or shiny
- symptoms keep coming back after treatment
If you get yeast infections often, our article on recurring yeast infections explains what a clinician will look at. Cleveland Clinic also suggests checking with a provider before you put a drugstore itch cream on the vulva, because what helps depends on the cause.
Frequently asked questions
Is cotton underwear really better for vulvar health?
For most people, yes. The NHS and Cleveland Clinic both recommend cotton, and one survey linked a non-cotton crotch with yeast infections. Cotton is soft and lets air through, though it holds sweat. If your underwear is a synthetic blend, a cotton gusset, the panel that touches the vulva, gives you most of the benefit.
Are thongs bad for your vulva?
Not on their own, according to the research. A survey of nearly 1,000 women found thong use wasn't linked with urinary tract infections, yeast infections or bacterial vaginosis, while a non-cotton crotch was linked with yeast infections. Fabric and fit matter more than style. If a thong rubs or irritates, that's a reason to switch.
Is silk underwear good for sensitive skin?
It may help skin that's already easily irritated. In one small trial, women with a vulvar skin condition who wore silk briefs went longer without needing their ointment than those in cotton. The study had only 20 women, so it isn't proof, but smooth, low-friction silk is a reasonable option to try.
Should I sleep without underwear?
Many people find it comfortable, and Cleveland Clinic lists going without underwear as an option for an itchy, irritated vulva. Night is the easiest time to give the skin air. If you'd rather wear something, loose cotton underwear or loose pyjama bottoms do much the same job.
What detergent should I use for underwear?
A detergent without fragrance, used in small amounts and rinsed well. An NHS vulva care leaflet suggests non-biological detergent or plain water for underwear, and says fabric conditioner contains possible skin irritants. Skip softener and dryer sheets, and wash new underwear before you wear it.
Can synthetic underwear cause yeast infections?
It may play a part. One survey of nearly 1,000 women found a non-cotton crotch was associated with yeast infections, although a survey shows a link, not proof of a cause. The NHS advises cotton underwear and avoiding tight underwear for people prone to thrush. Repeated infections still need a clinician's assessment.
Sources
- Synthetic underwear as an irritant, cotton or no underwear, flares with heat and sweat: Cleveland Clinic, Vulvar dermatitis
- Cotton underwear and avoiding tight underwear: NHS, Thrush
- Thongs, fabric and urogenital infections: Hamlin and others, Journal of Obstetrics and Gynaecology Research, 2019, PubMed 30916426
- Silk or cotton briefs in a vulvar skin condition: Corazza and others, Menopause, 2015, PubMed 25608275
- Loose cotton underwear and washing advice: Kent Community Health NHS, Vulva care
About this article
Written by the Peach & Cream team, based in Montréal. Published October 15, 2026. Last updated October 15, 2026. Medical facts come from the NHS, Cleveland Clinic and peer-reviewed studies, linked above. This article is general information, not medical advice.