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Vaginal microbiota transplants (VMT) have drawn interest as a possible treatment for vaginal dysbiosis, yet a randomised controlled trial reveals why they are not yet delivering the results researchers hoped for.
Without antibiotic pretreatment, VMT fared no better than placebo at restoring a protective, Lactobacillus-dominated vaginal microbiome – at six months, 11% of VMT recipients converted versus 25% of those on placebo.1
In our experience here at My Vagina, we see people chasing the newest microbiome idea before the basics have been sorted – what is driving the dysbiosis? VMT is interesting science, however as yet it is not a treatment you can access or rely on – and the trial data explain why. The trials show the idea has legs, and we’re excited to see where it ends up.
What does the trial show?
In a single-centre, double-blind, randomised controlled trial at a Copenhagen hospital, 49 people aged 18 to 40 with molecular vaginal dysbiosis received either a VMT or placebo in a 3:1 ratio, given once in each of three successive menstrual cycles. No participant received antibiotic pretreatment before transplantation.1
At six months after the last treatment, the results were sobering. VMT did not produce a significant shift to a Lactobacillus-dominated microbiome compared with placebo – 11% of VMT recipients had converted, against 25% on placebo. Without preparatory treatment, VMT alone was not enough to reliably restore protective bacteria.1
Donor engraftment: a bright spot
There was a more encouraging finding. Among the small number who did shift to Lactobacillus dominance, donor strains engrafted in about half of those tested – two of four in the main trial – and where engraftment occurred the donor strain could remain dominant for up to 199 days.1
More promising still, an extension phase added an antiseptic pretreatment before a further VMT: five of ten people in the antiseptic arm converted (around 50%), compared with none in the saline-plus-VMT or antiseptic-only arms.1
This echoes the first published VMT case series, in which women with intractable BV received transplants after antibiotic pretreatment and four of five achieved lasting remission with donor engraftment – an early hint that preparing the vaginal environment first may be what lets a transplant take.2
What is holding VMT back?
Several challenges emerge from this trial and related research:1
- Resident bacteria appear to resist replacement. Without pretreatment to reduce the existing bacterial load and biofilm, donor bacteria struggle to establish.
- Donor graft quality varied. In this trial the donor samples were dominated by Lactobacillus iners, a less stable species, whereas Lactobacillus crispatus was more common in those who converted.
- Antiseptic pretreatment looks important. The extension data suggest that reducing bacterial load and biofilm first may create ‘space’ for donor bacteria to take hold.
- The procedure was feasible and safe, with no serious adverse events, but it remains experimental and is not yet a clinically available treatment.
Where next for VMT?
VMT remains in the experimental phase, but the picture is becoming clearer. Optimised protocols – particularly those adding a preparatory antiseptic or antimicrobial step – may improve success rates. The durability seen in those who did engraft shows the potential is real; the challenge is enabling more transplants to take.1
Research continues into refined pretreatment strategies, better donor-matching techniques, and more efficient delivery methods. For now, VMT is best viewed as a promising avenue that needs further refinement rather than a ready clinical solution.1
Frequently asked questions
What is vaginal dysbiosis?
Vaginal dysbiosis is an imbalance in the vaginal microbiota, marked by a loss of protective bacteria (typically Lactobacillus species) and an overgrowth of disruptive bacteria such as Gardnerella, Fannyhessea vaginae and Prevotella. It can be associated with bacterial vaginosis (BV), recurrent yeast infections and other gynaecological issues.1
Why might pretreatment help with VMT?
An antiseptic or antibiotic step before transplant reduces the existing bacterial load and biofilm, lowering competition so donor bacteria can colonise more readily. Without pretreatment, resident disruptive bacteria may prevent new strains from establishing.1
Is VMT safe?
In this trial no serious adverse events were reported, and the researchers judged the procedure feasible and safe. Safety in practice depends on thorough donor screening for infections – such as HIV, herpes and human papillomavirus (HPV) – so screening protocols must be rigorous.1
How is a vaginal microbiota transplant performed?
A donor’s vaginal sample, rich in protective bacteria, is collected, processed and introduced into the recipient’s vagina. The procedure is minimally invasive and typically involves a single or repeated application.1
Are there alternatives to VMT right now?
Yes. Oral or vaginal probiotics containing Lactobacillus strains, antimicrobial agents (such as clindamycin or metronidazole for BV), and pharmaceutical-grade probiotics known as live biotherapeutic products offer evidence-based options. Some people also find dietary, lifestyle and behavioural changes helpful in supporting a protective vaginal microbiome.
What is the difference between VMT and single-strain L. crispatus probiotics?
VMT transplants the whole microbiota from a donor. By contrast, a live biotherapeutic product – essentially a pharmaceutical-grade probiotic – contains a single, well-characterised strain such as Lactobacillus crispatus CTV-05, produced and quality-controlled like a medicine. These single-strain products are further along in clinical development and offer a more standardised, scalable approach.
Could VMT work for conditions other than dysbiosis?
In theory, VMT could be explored for conditions linked to dysbiosis – such as recurrent BV or chronic vulvovaginal candidiasis – but clinical evidence is limited. Research is ongoing.
How much does a vaginal microbiota transplant cost?
VMT is not yet a widely available commercial procedure. Where it is offered, it is usually within research settings. Once the approach is refined and enters clinical practice, pricing will depend on regulatory status, donor screening and the healthcare setting.
Will VMT ever replace antibiotics for BV?
It is unlikely to replace them, but it may complement them. Antibiotics are fast-acting and well-proven for symptomatic BV. VMT may prove valuable for preventing recurrence, for maintenance, or for people who do not tolerate conventional therapy – but further research is needed.
What does the future hold for VMT?
The field is moving towards refined protocols incorporating pretreatment, better donor screening, and possibly enriched or carefully selected donor samples. Expect incremental progress over the next three to five years.
What to do next
If you are struggling with recurrent vaginal dysbiosis or BV, your first steps should be:
- Get a diagnosis and rule out other infections such as yeast infections and sexually transmitted infections.
- Ask your practitioner about evidence-based treatments: prescription antimicrobials for acute BV, then probiotics or lifestyle measures for recurrence prevention.
- Consider a thorough PCR or NGS vaginal microbiome test to identify your specific bacterial composition and guide personalised recommendations.
- Explore single-strain Lactobacillus live biotherapeutic products or oral Lactobacillus probiotics, which have stronger evidence than VMT at present.
- Keep an eye on VMT research – clinical protocols are improving, and it may become a viable option in coming years as data accumulate.
This is general information, not a substitute for personalised medical advice. If you have symptoms or concerns, please see your own practitioner.
References
- Wrønding T, Vomstein K, Lundgaard AT, et al. Vaginal microbiota transplantation for treatment of vaginal dysbiosis without the use of antibiotics: a double-blind, randomised controlled trial in women with vaginal dysbiosis. The Lancet Microbe. 2026;7(4):101294. Full text
- Lev-Sagie A, Goldman-Wohl D, Cohen Y, et al. Vaginal microbiome transplantation in women with intractable bacterial vaginosis. Nature Medicine. 2019;25(10):1500–1504. Full text
