While down your virtual rabbit hole, you might have come across boric acid suppositories, a compound which claims to help disrupt a cycle of infections.
But testimonials can be conflicting: while some say it knocked out their recurrent BV or yeast infection when nothing else worked, others will warn of uncomfortable side effects and express concerns about safety.
In these cases, it can be hard to know which information is well researched and science-backed.
That’s why we’ve broken down the ins and outs of boric acid for vaginal infections below:
First off, what is boric acid?
Boric acid is a white powder composed of boron, oxygen, and hydrogen and made from borax, a naturally occurring mineral. When it’s used for vaginal health, it comes in the form of powder or a capsule to insert vaginally as a suppository. It’s known to have antimicrobial and antifungal properties that emerging research suggests may help with recurrent vaginal infections.
FYI, generally, boric acid prescribed by a doctor like the boric acid you can get through clinical care with Evvy tends to be more pure and less likely to cause adverse reactions than boric acid purchased OTC or on Amazon.
Is it safe to put boric acid in your vagina?
Boric acid suppositories for vaginal use are not generally considered dangerous, in the short term, and when taken as prescribed or medically advised.
Boric acid’s link to borax is where many people’s potential concerns over safety come in. It’s made from the same mineral compound as borax (sodium borate decahydrate), which is used in some household cleaning products and pesticides.
Putting a household cleaner ingredient in your vagina would be disastrous. But despite sharing the same compound, boric acid and borax are not the same things.
Boric acid suppositories are only for inserting into your vagina. They should never be taken orally because they can be toxic if eaten in “extreme amounts” (15-20 grams for adults and 5 grams for infants).
However, boric acid vaginal suppositories are typically 600 milligrams and are generally considered safe if used as directed: inserted in the vagina, not consumed orally. To put it another way, an adult would need to consume 25 vaginal capsules at once in order to reach toxic levels.
What about the side effects of boric acid I’ve read about?
Vaginal boric acid first-timers can feel anxious about the potential side effects. But a 2011 review in the Journal of Women’s Health found that only 10% of participants, across multiple studies, reported boric acid side effects, from vaginal use.
A similar, but more recent review (2021) backed up these findings, concluding that (vaginally inserted) boric acid treatment was safe for most people.
The review also pointed out that there was barely any (if at all) absorption of boric acid into the bloodstream, over two weeks of using it vaginally.
However, there are currently no studies examining the safety of long-term vaginal boric acid treatment, and, given how many people with vaginas use or consider using boric acid, the lack of research has ‘gender health gap’ written all over it.
Common side effects of vaginal boric acid include:
- A rash, redness, or irritation around (or in) the vagina
- A burning sensation in the vagina
- A gritty sensation in the vagina
- Watery discharge
Who shouldn’t be using boric acid suppositories?
Pregnant people would generally be advised against using intravaginal boric acid.
The safety data available on vaginal use of boric acid can’t automatically be applied to pregnant people. For this group (and the developing fetuses they carry), there isn’t enough data available to give it a thumbs up for safety and it’s better to err on the side of caution here.
Ok, but will boric acid help treat my yeast infection(s)?
Existing research points toward boric acid being quite good at treating yeast infections, especially when antifungals have failed, or a yeast infection keeps recurring.
Sometimes boric acid actually performs better than first-line treatment, like an antifungal for yeast infections, particularly when an atypical Candida species is at play.
For example, the CDC guidelines recommend 600 mg of boric acid in a gelatin capsule administered vaginally once daily for 3 weeks for recurrent non-albicans vulvovaginal candidiasis. However, like many other instances in vaginal health, there needs to be more research on the effectiveness of boric acid on all types of Candida.
Speaking of atypical Candida strains, a 2007 study of yeast infections in diabetic patients found boric acid suppositories solved 63.6% of Candida glabrata infections (a less common vaginal yeast species that can be resistant to OTC treatment, whereas Candida albicans causes most vaginal yeast infections).
By comparison, in the same study, fluconazole, which is commonly prescribed to treat yeast infections, only resolved 28.6% of infections. Some research suggests antifungal resistance is a growing problem when treating yeast infections.
If your yeast infections refuse to disappear or bounce back all the time, like a Marvel superhero, it may be worth talking to your doctor about vaginal boric acid.
A 2018 review of multiple studies that looked at the use of boric acid, vaginally, specifically recommends boric acid treatment for antifungal resistant yeast infections. We’ll be keeping an eye on the FDA and CDC guidelines to see how they evolve based on this emerging research!
So, does boric acid also work to treat BV?
BV is a tricky one and more complicated to treat overall than yeast infections.
Sometimes, the first-line treatment for BV (antibiotics) works, but then sparks a yeast infection, meaning you’ve essentially swapped one vaginal infection for another. Crying, screaming, throwing up (not literally but maybe emotionally and mentally).
A 2009 study looked into dual boric acid and antibiotic treatment for BV. It found a one week antibiotic course, followed by a three week course of vaginal boric acid, kept a whopping 87% of patients symptom free at 12 weeks (since diagnosis). Unfortunately, the positive results didn’t last for everyone. Three months after treatment stopped, symptoms returned for 50% of patients.
This is not surprising—BV recurrence can be hard to ward off, even with dual treatment. One of the reasons why finding a long-term cure for BV is so challenging is that certain BV-causing bacteria can form biofilms, hardy little walls of bacteria that antibiotics aren’t able to penetrate.
As you can imagine (or may know from first-hand experience) a sticky biofilm wallpaper full of harmful bacteria, stuck to your vaginal walls…isn’t ideal.
That’s why researchers hope that combining boric acid with a chemical like EDTA, that breaks up biofilms, could improve outcomes. TOL-463, a new vaginal medicine that recently underwent Phase II clinical trials (also mentioned above), is exactly that; a combination of boric acid and EDTA. The results indicate that 88% to 93% of BV patients reported symptom resolution at the end of treatment, however, a majority of BV patients were later prescribed additional treatment. While this might sound discouraging, it is not surprising. You have to remember that this study was done TOL-463 alone, not in combination with antibiotics. These data suggest that boric acid might indeed be helpful, but it is no silver bullet.
P.S.: If you have recurrent bacterial vaginosis and suspect a biofilm may have formed, an Evvy test will help you identify if the bacteria causing your BV are capable of forming a biofilm.
How do I know if boric acid is working as a treatment?
Taking an Evvy test before using boric acid (while you have symptoms) and after will help you understand if the treatment is actually helping your vaginal microbiome shift to a more protective state. An Evvy Membership unlocks our Compare feature, which allows you to view your microbes side by side along with the products used at each test and your symptoms at that time.
Should boric acid be my first choice treatment?
For yeast infections, one study concluded that vaginal boric acid is at least just as effective as antifungals if not better. Research on boric acid for BV has less clearly compelling outcomes (although research still shows it is clinically effective). Regardless, boric acid is not yet FDA-approved as a treatment for vaginal infections even though it's considered generally safe by most researchers and clinicians and many users tout its effectiveness.
But the creators of the dual boric acid and EDTA treatment (TOL-463), Toltec Pharmaceuticals, could change this if TOL-463 completes its clinical trials, and goes on to secure FDA approval. In the short term, it shows promise as a yeast infection treatment (with a 77%-88% cure rate one-week post-treatment), as well as for BV.
Even without FDA approval, boric acid suppositories can still be prescribed by an OB-GYN, for vaginal use. Typically it’s much better to use boric acid prescribed by a doctor because it tends to be more pure and less likely to cause adverse reactions than boric acid purchased OTC. So let your OB-GYN guide you on this, especially if other treatments haven’t worked.
You may also want to consider leveraging an Evvy test to identify which species of candida may be present (since boric acid is only CDC recommended for glabrata) or knowing whether you have bacteria that are known to create biofilms, since those are the two situations in which research has shown it is effective.