BV came back by week 12 in 30% vs 45% on placebo. Side effects were similar in both groups.
Cohen 2020, N Engl J Med · Source
Lactobacillus crispatus
Strain UALcr-35 (UAS Labs)
Often the main lactobacillus in a healthy vagina, and one of the species researchers most often find when lactobacilli are thriving there.
Nativeoften the main lactobacillus in a healthy vagina
228women in a trial of a related strain after BV treatment
10strains in the Daily Probiotic blend
Why we love it
We wanted the blend to include a species that is naturally common in the vagina. L. crispatus is one of the species researchers most often find when the vaginal microbiome is dominated by lactobacilli, so it was an easy choice to include.
What does the research show?
Bacterial vaginosis
In a trial of 228 women who had just finished BV treatment, a vaginal product with L. crispatus CTV-05 was compared with a placebo. By week 12, BV had come back in 30% of the CTV-05 group and 45% of the placebo group. A smaller Estonian trial gave oral or vaginal capsules of two other L. crispatus strains to 89 women with BV and looked at Nugent scores, a lab measure of BV.
Yeast infections
In the same Estonian trial, 93 women with vaginal yeast infections took oral or vaginal capsules of three L. crispatus strains or a placebo. Researchers tracked discharge and itching scores over three months.
Urinary tract infections
In 100 women with recurring UTIs, a vaginal L. crispatus CTV-05 product was compared with a placebo. Recurrence was 15% versus 27%, a difference too small to be sure it was not chance.
Getting to the vagina after oral use
In a small study, 20 women took an oral L. crispatus NTCVAG04 capsule. The strain was found in vaginal samples from 8 of 12 women who could be assessed. In two other trials, oral strains showed up in stool but not, or not clearly, in the vagina.
Studies
Human study tested in people Lab study tested in the lab
Studies on other strains of this species
Average Nugent score fell from 7.6 to 4.4 in both the oral and the vaginal groups in the first month. It changed little with placebo.
Mändar 2023, Benef Microbes · Source
Discharge and itching scores dropped within 4 weeks in both active groups, not significantly with placebo.
Mändar 2023, Benef Microbes · Source
Nugent scores were lower with the oral mix than with placebo. Only 36 of the women had BV.
de Vrese 2019, Benef Microbes · Source
Adding the oral mix did not improve cure rates. The strains were found in stool but not in the vagina.
Qi 2023, Front Immunol · Source
UTIs came back in 15% vs 27%, not a statistically significant difference.
Stapleton 2011, Clin Infect Dis · Source
Strain found in vaginal samples from 8 of 12 assessed women after two 14-day courses.
Lazzeri 2023, Minerva Obstet Gynecol · Source
Which strain do we use?
Our strain is L. crispatus UALcr-35 (UAS Labs). It was also one of 10 strains in a small oral blend study (Martoni 2022), where vaginal pH fell slightly over 28 days. The other studies above used other strains of this species, and results belong to the strain tested.
Is L. crispatus safe to take?
In the trials above, side effects were similar to placebo. Some women in an oral trial found the capsules hard to swallow. If you are immunocompromised, have a central line, are critically ill, or are pregnant or breastfeeding, ask your clinician before taking any probiotic.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Last reviewed: November 2026.
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Reviewed by the Momotaro Apotheca medical team, including OB-GYNs and naturopathic doctors. Educational information, not medical advice. All ingredient research