If you have bacterial vaginosis or a yeast infection, you may be wondering about the difference between boric acid and probiotic pessaries. You may also be wondering if you need one or the other, or both, and where to get boric acid in Australia. The main difference is that these are both products that are inserted into the vagina, but they work in very different ways.

CAUTION: Before we move on, please take note that Boric acid is highly toxic and boric acid pessary should NEVER be consumed orally. It should also never be left unattended where there is any possibility that children or pets may be able to access or ingest it.

Boric acid is a substance that has been used for a number of years around the world to kill yeast infections. Probiotics are good bacteria that work to balance the bacteria in the vagina (balancing the vagina’s microbiome), which can support and maintain vaginal health.

In this article, we cover:

1. What are boric acid pessaries or suppositories?
2. Can boric acid help yeast infections?
3. Can boric acid help bacterial vaginosis?
4. What are the risks and potential side-effects of using boric acid?
5. What are vaginal probiotics?
6. When would I use boric acid vs vaginal probiotics?
7. What’s the difference between boric acid and vaginal probiotic suppositories?

What are boric acid pessaries or suppositories?

Boric acid is a colorless crystal or white powder with no odour, which is slightly oily when touched. It is a very weak acid and has a pH value of 5.1 (0.1 molar)¹.

Vaginally applied boric acid represents one of the treatment options available for thrush which is resistant to azole antifungal treatments. Boric acid is included as part of multiple national health guidelines globally (including the United Kingdom and the United States) for the treatment of vaginal yeast infections or recurrent bacterial vaginosis.

Can boric acid help yeast infections?

Boric acid is commonly used to treat yeast infections in the vagina because it can kill many types of microorganisms. Research has shown that it is more effective at stopping the growth of the fungus that causes thrush than some commonly used antifungal drugs such as fluconazole.

Boric acid was found to be effective in preventing the growth of Candida albicans and Candida glabrata², two types of fungus that can cause yeast infections in the vagina. Boric acid was able to inhibit the growth of these fungi, interfered with the formation of biofilm³ around them, and reduce their activity. In the same study these results couldn’t be achieved with fluconazole, another commonly used medication for yeast infections.

When it comes to clinical evidence and treatment of patients who suffer from vaginal yeast infections, usefulness of Boric acid was confirmed on non-albicans yeast infections^4,5 (that being infections caused by fungus species other than C. albicans). A study done on diabetic patients found that vaginal boric acid 600 mg used for 14 days was even more effective than oral fluconazole 150 mg for Candida glabrata vaginal yeast infection⁶.

Boric acid is a promising option to treat recurring yeast infections in the vagina. A safe dosage is 300-600 mg used vaginally twice a week. A study have shown that using 300 mg of vaginal boric acid for 14 days, followed by 300 mg for 5 days during menstruation for 5 months, is as effective as taking an oral antifungal medication called itraconazole. However, relapses of yeast infections six months following this treatment were common in both groups (54.5%)⁷.

Can boric acid help bacterial vaginosis?  

Both clinical research and practice have shown that using boric acid alone is not effective in treating bacterial vaginosis. However, it may help when used in combination with other antimicrobial agents⁸ that target bacteria.

A retrospective study looked at how well boric acid (600mg) worked to treat recurrent bacterial vaginosis when used vaginally 21 days after a course of antibiotics. If remissions occurred, a cream containing antibiotics called metronidazole was applied twice a week for 16 weeks. The study found that the treatment worked well initially, with a 92% success rate at 12 weeks, but the cumulative cure rate dropped to 50% after 9 months⁹.

What are the risks and potential side-effects of using boric acid vaginally?

Available data suggests that using boric acid in the vagina in doses commonly recommended by doctors (300 mg or 600 mg) is safe¹⁰. But please read the following cautions before proceeding.

CAUTION: Boric acid can cause death if consumed orally; boric acid products should be stored in a secure place that is inaccessible to children and pets.

CAUTION: Boric acid should NOT be used by individuals who are pregnant or attempting conception. Although topical exposure to boric acid is not likely to cause abnormalities of the fetus because boric acid absorption is limited, a weak teratogenic effect of intravaginal boric acid during pregnancy cannot be excluded³. This can cause congenital disorders in developing embryo or fetus.

Adverse effects reported in clinical studies were vaginal burning sensation (<10% of cases), watery discharge during treatment, and vaginal erythema¹¹ (a skin reaction).

Additionally, sexual partners of patients treated with vaginal boric acid have reported skin irritation after exposure¹². The intensity and length of risk to a sexual from the time of vaginal use of boric acid is not known. 

Why can’t I find boric acid?

If you’ve found it hard to get hold of boric acid suppositories, especially in Australia, you’re not alone. Different countries will have different regulations around it being sold as an over-the-counter product.

Boric acid is currently not available as an over-the-counter (OTC) product in the United States¹³. Therefore, non-prescription Boric acid products available in the USA are not FDA-approved products.  However, plenty of non FDA-approved products do exist and can be found on Amazon.

In Australia, Therapeutic Goods Administration (TGA) allows boric acid to be used as an active ingredient in biologicals, complementary medicines, OTC and prescription medicines. Complementary medicines are products that claim health benefits and health maintenance.

Despite this Boric acid vaginal products cannot be classified as complementary medicines in Australia for two reasons:

1. Vaginal yeast infection (candidiasis) and vaginal bacterial infections (bacterial vaginosis) are serious conditions that must be treated by the supervision of a licensed health professional rather than over the counter products. Complementary medicines are intended for use by a person for non-serious medical indications. 
2. The TGA puts certain restrictions on the maximum recommended daily dose in complementary medicines. The maximum recommended daily dose must not provide more than 6 mg of boron, which is around 34 mg of boric acid. This is too low to be considered as a therapeutic dose for treating vaginal infections.

When used as a complementary medicine, Boric acid is often part of multivitamin oral products or topical preparations.

Prescription medicines are drugs that due to their toxicity or potential for harmful effects, are not safe for use except under the supervision of a practitioner licensed by law to administer them.

Adequate directions for use of prescription medicine cannot be written in a way so that a person without medical training can use them safely. Therefore, a Boric acid product with high enough levels of concentration to be suitable for treatment of a vaginal infection fall into the category of prescription medicine in Australia and other countries, which in turn make getting hold of it more difficult. 

What are vaginal probiotics?

Vaginal probiotics are products which contain specific Lactobacillus strains which are clinically proven to support vaginal health. A good vaginal probiotic product will not just have the right bacteria/bugs, but also will be capable of delivering them to the right place.

Vaginal route of administration (usually in the form of pessary tablets or capsules) allows for targeted and fast action, directly delivering probiotic bacteria into the vagina. By arriving at the exact site of action vaginally, good bugs can directly replenish the vagina’s microbiome environment in their full strength, avoiding the digestive system. (In comparison if taken orally probiotics meant for the vagina will lose their strength or even their way completely, on their journey from the mouth to the vagina.)

Once in the vagina, probiotics get to work colonising it and producing beneficial substances like lactic acid that further protect and support healthy vaginal microbiome.

Clinical data supports the benefit of vaginal administration of probiotics and confirm this method’s advantages over orally administered probiotics. It was found that vaginally administered probiotics were 72% more effective in restoring vaginal microbiome in BV patients¹⁴ than oral probiotics.

When would I use boric acid vs vaginal probiotics?

The answer is that they are used for different purposes, and it is possible to use both: though most definitely not at the same time as each other.

Boric acid is most effective in vaginal yeast infections, especially those that are caused by non-albicans species, like Candida glabrata (which account for just 5-10% of all vaginal yeast infection cases¹⁵). However, it can be difficult to find boric acid and it is not possible to get without a prescription in Australia and other countries. Vaginal probiotics will repopulate the vaginal microbiome with healthy bacterial in order to maintain a healthy state, making infection less likely.

Certain vaginal probiotic strains have been clinically researched and found beneficial for restoring healthy vaginal microbiome^16,17.

Both boric acid and vaginal probiotics can support the antibiotic/antifungal treatments and improve therapy outcomes.