Which probiotics are best for women?

Kathy Wheddon Nutritional Therapist DipION

In short

For women's vaginal health, research shows that certain strains (specifically L. rhamnosusGR-1® and L. reuteri RC-14®, trialled in thrush, cystitis, and bacterial vaginosis) are more appropriate than other probiotics. This FAQ will help explain why. However, for general digestive health and immunity there is no research to suggest that the digestive system in men and women require different probiotic strains - so the best one for you depends on your individual needs and symptoms.

To stay happy and healthy, don't forget your 'intimate' flora!

In depth

When we are looking at the best probiotics for women to take, we need to consider the needs of two separate anatomical areas, namely the GI tract and the urogenital tract.

Due to the proximity of the vagina to the anus, it is much easier in women for pathogenic bacteria to cross over from the GI tract to the urogenital tract and cause a situation of dysbiosis there, than it is in men. The flora of a healthy vagina is made up of different strains of bacteria to the gut flora, and hence should be considered separately when you are choosing a probiotic.

The rest of this FAQ will look at the specific needs of women to maintain the health of these two different colonies of bacteria.

A large amount of research demonstrates that some probiotic strains (specifically L. rhamnosus GR-1® and L. reuteri RC-14®, trialled in thrush, cystitis, and bacterial vaginosis) are more appropriate than others to support female intimate health, and this FAQ will go on to explain how and why this applies.

1) Women's Intimate Flora:

New and wider-reaching, clinical applications for probiotics are emerging all the time. One of these emerging areas of research is the role of probiotics in women’s health, and specifically in women's intimate health.

Beneficial flora, or probiotics, inhabit the urogenital tract (this spans the urinary tract and vaginal tract in women) as well as the gut. In the vagina and urinary tract, probiotics are thought to exert many of the same beneficial effects as they would in the gut; their presence limits the likelihood of pathogenic bacteria and yeasts being able to overgrow.

Clinical trials have shown that a number of strains of Lactobacillus are particularly effective at helping female intimate health problems such as cystitis, thrush and bacterial vaginosis. These specific strains (in particular Lactobacillus rhamnosus GR-1® and Lactobacillus reuteri RC-14®) have been clinically trialled to survive transit through the gut, and then successfully colonise the vagina and bladder where they exert their beneficial effects.

Due to the ease with which microorganisms can transfer from the anus to the vagina, and then spread via the urethra to the bladder to the urogenital tract, it is thought that most urogenital infections such as thrush, cystitis and bacterial vaginosis stem from pathogens in the intestines. Following this line of thought, it seems a reasonable assumption to make then, that taking probiotic supplements can positively affect the flora of our urogenital tracts and therefore either help treat or prevent UTIs and vaginal infections.

There have been a number of clinical trials that support this theory, including a 2004 study1at the Canadian Research and Development Centre for Probiotics. This study; a randomised, placebo-controlled trial, showed that the vaginal microflora in women with Bacterial Vaginosis (BV) was restored to a more favourable, Lactobacilli-dominant environment following 2 months of a daily oral intake of the probiotics Lactobacillus rhamnosus GR-1®and Lactobacillus reuteri RC-14®.

As always we should emphasise that, not all strains are equal when it comes to probiotics, and there is no exception for probiotics for women's health. An Italian study2 in 2004 looked at the specific strains of Lactobacilli that are able to survive the gastrointestinal tract intact in order to then colonise the vagina. The study summarised that "L. rhamnosus GR-1® and L. reuteri RC-14® can be delivered to the vaginal environment even if they are taken orally." And "Their administration results in significant changes in the vaginal flora in terms of increased Lactobacilli presence…"

An article3 in the ‘World Journal of Urology’ in 2006 further validated this evidence, and stated that when it comes to the prevention of urinary tract infections, not all Lactobacilli are effective. It named Lactobacillus rhamnosus GR-1® and Lactobacillus reuteri RC-14®, alongside a third strain Lactobacillus reuteri B-54 as the only strains that have demonstrated their ability to survive the digestive tract and then successfully colonize the vagina and bladder.

Due to fluctuating hormone levels some women find that they may become more prone to vaginal dysbiosis at certain points in their menstrual cycle. If vaginal or urogenital tract infections, such as thrush, bacterial vaginosis or cystitis are a problem for you, then selecting a supplement that contains the well researched Lactobacillus rhamnosus GR-1®and Lactobacillus reuteri RC-14® strains of probiotic would perhaps be the most effective at helping to support health in the female intimate area.

2) Gut flora:

As mentioned, the vaginal flora will require different strains to those recommended for gut health. Whilst the question of the best probiotic strains for digestive health conditions is not gender-specific, here we explore a few digestive conditions which are reportedly more common in women.


One symptom to look at when discussing probiotics specifically for female digestive health, is the problem of bloating, which is reported to be much more common in women than men. This can either be a constant problem, or the bloating can be cyclical and worsen at certain points in the menstrual cycle, due to fluctuating hormone levels.

Bloated woman
For women suffering with bloating a probiotic specific to bloating is most effective

Whilst both situations have slightly different physiological causes, the result is the same; digestion is impaired and food is not effectively broken down, causing bloating and wind.


If constipation is involved (again a condition reported to be much more common in women), a probiotic supplement containing B. lactis BB-12 would be the best. Bifidobacterium lactisBB-12 along with FOS (a prebiotic) helps gently ease/discourage constipation and encourage the proliferation of good bacteria in the colon. Avoiding constipation is important when managing hormonally related conditions as ‘old’ or spent hormones that have been processed by the liver, are eliminated via the faeces. When constipated, these hormones can be re-absorbed back in to the bloodstream from the faecal matter due to the longer transit time, leading to hormonal disturbances.

Foods that prevent constipation should also be considered, alongside specific herbs and nutrients that help to balance hormones, such as magnesium and vitamin B6. (N.B. it is always advised that you should seek the advice of a qualified healthcare professional to find the most suitable combination of supplements for your needs).

For more information regarding probiotics and digestive health, read about probiotics and IBS here.


When selecting a probiotic supplement it is advised that you choose a product based on your own personal requirements and symptoms. Men and women have the same basic flora in the gut, so gender on its own is not a factor when it comes to selecting the right probiotic for digestive health. The only implication of gender on our balance of intestinal flora comes from the effect that the various sex hormones have on it, and the tendency for some women to experience GI upset at certain points in their menstrual cycle.

You can read more about women and probiotics here:

2 amazing things women are doing with bacteria, that you didn't know about.


1) Canadian Research and Development Centre for Probiotics ‘Nucleic acid-based diagnosis of bacterial vaginosis and improved management using probiotic lactobacilli’ 2004, J Med Food, p223-228.

2) Instituto di Microbiologia, Facolta di Agraria ‘Utilisation of the Intestinal Tract as a delivery system for Urogenital Probiotics’, 2004, J Clin Gastroenterol, p38

3) ‘Probiotics to prevent urinary tract infections: the rationale and evidence’ 2006. World J Urol. P28-32