No Evidence Supports Not Wearing Underwear to Reduce UTI or Vaginal Infection Risk
There is no scientific evidence that going without underwear reduces the risk of urinary tract infections or vaginal infections. In fact, the available evidence suggests that underwear fabric type matters more than wearing versus not wearing underwear, and recent data even suggests antimicrobial underwear may provide benefits.
What the Evidence Actually Shows
Underwear Style Doesn't Matter
A large cross-sectional study of 986 women found that thong underwear use was not associated with increased rates of UTIs, yeast vaginitis, or bacterial vaginosis 1. This directly contradicts the common belief that certain underwear styles promote infections. The study identified that oral sex was the only independent predictor of UTI and bacterial vaginosis, while noncotton crotch fabric (not style or presence/absence of underwear) was associated with yeast infections 1.
Fabric Type Is What Matters
When counseling patients about underwear and infection risk, focus the conversation on fabric choice rather than whether to wear underwear at all 1. Cotton or breathable fabrics that wick moisture are preferable to synthetic materials that trap heat and moisture.
Antimicrobial Underwear May Actually Help
Contrary to the notion that no underwear is better, a 2026 prospective study found that antimicrobial underwear used alongside standard treatment significantly improved vaginal symptoms and microbiological outcomes 2. The antimicrobial underwear group showed marked improvement in discharge (96.7%→6.9% vs. 72.5%→27.5%), pruritus, odor, and irritation, with negative cultures increasing from 40% to 80% 2.
Evidence-Based Prevention Strategies That Actually Work
Rather than advising patients to forgo underwear, current guidelines recommend these proven interventions 3, 4:
For All Women with Recurrent UTIs:
- Increase fluid intake by 1.5L daily (low-risk intervention with RCT support) 3
- Methenamine hippurate 1g twice daily (strong recommendation, noninferior to antibiotics) 3, 4
- Consider cranberry products with 36mg proanthocyanidins 3
For Postmenopausal Women:
- Vaginal estrogen therapy (strong recommendation, multiple delivery methods available) 3, 4
- This addresses the root cause: estrogen loss leads to vaginal microbiome changes, loss of protective Lactobacillus species, and increased UTI risk 3
Common Pitfalls to Avoid
Don't focus on underwear presence/absence when discussing hygiene with patients. The 1985 study that suggested clothing associations with UTI 5 is outdated and has been superseded by higher-quality evidence showing no such relationship 1.
Absorbent pad use (not regular underwear) is associated with increased UTI risk in nursing home residents 6, but this is a different clinical scenario involving incontinence products, not standard underwear.
The Bottom Line
Advise patients to wear breathable, cotton-crotch underwear rather than going without underwear. Direct prevention efforts toward evidence-based interventions: increased hydration, methenamine hippurate, vaginal estrogen for postmenopausal women, and addressing sexual practices that increase risk 3, 4, 1.