Can a patient develop a urinary tract infection (UTI) or vaginal infection if they do not wear underwear?

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Last updated: September 13, 2026 • View editorial policy

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No Underwear Does Not Increase Risk of UTI or Vaginal Infections

Not wearing underwear does not cause or increase the risk of urinary tract infections or vaginal infections. The available evidence shows that underwear style (including thong vs. brief) has no association with urogenital infections, and there is no scientific basis to suggest that going without underwear would be harmful 1.

Evidence on Underwear and Infection Risk

The most relevant study directly addressing this question found that underwear style is not a risk factor for UTIs or vaginal infections 1. In a large cross-sectional study of 986 women:

  • Thong wearers (who have minimal fabric coverage) had no increased rates of UTIs, yeast vaginitis, or bacterial vaginosis compared to women wearing full briefs
  • The only independent predictor of UTI and bacterial vaginosis was oral sex
  • Noncotton crotch fabric (not style) was associated with yeast vaginitis
  • Medical providers should focus on sexual practices and underwear fabric rather than style when counseling patients 1

Similarly, research on panty liners (which create a barrier between skin and underwear) found no evidence that they promote vulvovaginal candidiasis or UTIs, despite concerns about trapping heat and moisture 2.

What Actually Matters for UTI and Vaginal Infection Risk

Based on current guidelines and research, the relevant risk factors are:

For UTIs 3, 4:

  • Sexual intercourse (most significant modifiable risk factor)
  • Use of spermicides or diaphragms
  • Personal hygiene practices (wiping direction, delayed voiding after intercourse)
  • Anatomic/functional urinary tract abnormalities
  • Postmenopausal status
  • History of previous UTIs

For Vaginal Infections 5, 6:

  • Disruption of vaginal lactobacilli (the protective vaginal microbiota)
  • Sexual practices
  • Antibiotic use that alters vaginal flora
  • Hormonal changes (particularly postmenopausal estrogen deficiency)

Minor associations found in older research 7:

  • Tampon use and soft drink consumption showed modest associations with UTI (RR ≥1.4)
  • However, this 1985 study had methodological limitations

Clinical Bottom Line

Reassure patients that not wearing underwear will not cause UTIs or vaginal infections. The focus should be on:

  • Fabric choice if wearing underwear: Cotton crotch preferred over synthetic materials 1
  • Sexual health practices: Voiding after intercourse, discussing barrier methods
  • Proper hygiene: Front-to-back wiping, adequate hydration
  • Vaginal microbiome health: Avoiding unnecessary antibiotics, considering vaginal estrogen in postmenopausal women if recurrent infections occur

The common belief that underwear is necessary to prevent infections is not evidence-based. Personal comfort and preference should guide this choice.

References

1
Research

Brief versus Thong Hygiene in Obstetrics and Gynecology (B-THONG): A survey study.

The journal of obstetrics and gynaecology research, 2019

2
Research

Do panty liners promote vulvovaginal candidiasis or urinary tract infections? A review of the scientific evidence.

European journal of obstetrics, gynecology, and reproductive biology, 2007

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.