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ingestible · for urinary health & uti prevention

Lactobacillus rhamnosus GR-1 & L. reuteri RC-14 Probiotic

Reviewed by the Nimbera editorial team · Last updated May 2026

Beerepoot 2012 Arch Intern Med (PMID 22782199) - double-blind RCT of 252 postmenopausal women; L. rhamnosus GR-1 + L. reuteri RC-14 substantially reduced UTI frequency (mean 7 UTIs/year reduced to 3.3 in probiotic group vs 2.9 in antibiotic group) without inducing antibiotic resistance, though did not meet noninferiority vs antibiotic.$20-$40/month

How to use

Take one oral capsule daily containing L. rhamnosus GR-1 and L. reuteri RC-14 (minimum 10^9 CFU of each strain). The specific strains GR-1 and RC-14 are the ones with the best evidence base - not all Lactobacillus products are equivalent. Take consistently for at least 3-12 months for recurrence prevention. Refrigerated products generally maintain higher viability.

How it works

Lactobacillus species dominant in a healthy vaginal microbiome produce lactic acid, hydrogen peroxide, and bacteriocins that create an acidic environment hostile to uropathogenic bacteria such as E. coli. Oral administration of GR-1 and RC-14 strains has been shown to colonise the vagina after GI transit and restore a protective Lactobacillus-dominant environment, reducing the pool of pathogens in the periurethral zone that seed ascending UTIs.

Where to buy

Jarrow Formulas Fem-Dophilus (contains GR-1 + RC-14 strains, widely available), Culturelle UT Advantage, RepHresh Pro-B. Available at CVS, Walgreens, Whole Foods, Amazon, and iHerb. Ensure the product specifically lists L. rhamnosus GR-1 and L. reuteri RC-14 strains by designation.

Typical cost: $20-$40/month

Safety notes

Very safe in immunocompetent individuals. Rare cases of probiotic bacteremia have been reported in severely immunocompromised patients - avoid in patients with central venous catheters, short bowel syndrome, or active immunosuppression without physician supervision. May cause mild initial bloating or GI discomfort. Does not induce antibiotic resistance - a clinically significant advantage over long-term antibiotic prophylaxis.

Drug & supplement interactions

  • Always tell your doctor or pharmacist about any supplements you take.
  • Interactions can occur with prescription medications, blood thinners, and immunosuppressants.
  • Herbal remedies can affect how the body absorbs or metabolises drugs.
  • Check drugs.com interactions checker before starting.

Clinical source

Beerepoot 2012 - Arch Intern Med (PMID 22782199)

This information is compiled from primary clinical literature and is for informational purposes only. It is not a substitute for professional medical advice. Read our full disclaimer.