Doctors may recommend using boric acid for a yeast infection as a second-line treatment when other antifungal medications are not working.

Boric acid works by preventing Candida fungi from growing. This type of fungus supports the development of yeast infections.

Boric acid is available as vaginal suppositories.

In this article, we look at the research behind boric acid as a treatment for yeast infections, its effectiveness, and possible risks.

Doctor and patient. boric acid for yeast infection. Doctors may recommend using boric acid to treat yeast infections. Share on Pinterest
Doctors may recommend using boric acid to treat yeast infections.

It is healthy to have small amounts of yeast on the skin and in areas of the mouth, throat, and vagina. Under some conditions — such as when the immune system is weak or when hormones change during pregnancy — the yeast may multiply and cause an infection.

The medical term for a yeast infection is candidiasis. Yeast infections are common and often occur in the vagina. They are frequently caused by Candida albicans (C. albicans) or Candida glabrata (C. glabrata ) fungi.

Boric acid is a white powder or crystalline solid that acts as a strong antiviral and antifungal agent in the body. Research suggests that boric acid restricts the growth of both C. albicans and C. glabrata. It interferes with the yeast’s natural life cycle, preventing it from growing to become infectious.

According to the Centers for Disease Control and Prevention (CDC), people should use boric acid as a secondary treatment, that is, if other antifungal drugs or ointments are unable to treat the yeast infection or if it recurs.

Boric acid may be able to treat infections that are resistant to first-line treatment. This is usually an antifungal medication, which may involve a single oral dose of fluconazole or a topical antifungal cream. If these do not work, a doctor may recommend using boric acid or another treatment, such as nystatin or flucytosine.

A person can use a gelatin capsule as a vaginal suppository. The CDC recommend using capsules that each contain 600 mg of boric acid once a day for 2 weeks.

Boric acid medications are usually affordable. They are available for purchase over the counter at drug stores or online.

If symptoms persist after using boric acid, speak to a general practitioner or gynecologist.

Research indicates that boric acid is effective in treating Candida infections, including cases that do not resolve with common antifungal medications. People with recurrent yeast infections may benefit most from boric acid treatment.

Authors of a 2011 medical review report that boric acid is a safe and economical option for people with recurrent or chronic vaginal infections, especially when conventional treatment is ineffective.

A growing body of evidence shows that, when a person uses the optimal concentration, boric acid has fewer side effects than standard ointments.

Some common side effects of boric acid use include:

A person with any of the following should not use boric acid capsules:

It is important to remember that boric acid is toxic. If a person uses it incorrectly, it can cause a fatal overdose, though this is rare.

Do not take boric acid orally or apply it to open wounds. Consult a doctor before using this medication while pregnant.

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It is important to follow the instructions when using suppositories.

Boric acid vaginal suppositories are available for purchase. They are solid, oval-shaped capsules that a person inserts into the vagina. They become liquid as they warm up to the body’s temperature.

To treat a Candida infection, the CDC recommend using vaginal suppositories containing 600 mg of boric acid each. A person should use them once a day for 2 weeks.

Always follow the instructions on the medication’s label.

Before using a vaginal suppository, make sure the hands and vaginal area are clean and dry to prevent bacteria from entering the body.

To use a suppository, a person should:

  • Fill the applicator and lie on the back with the knees bent or stand with one foot raised on a chair.
  • Insert the applicator gently into the vagina.
  • Press the plunger to release the capsule.
  • Gently remove the applicator.

Some instructions recommend using a suppository before bed. This is because lying down will reduce the risk of medicine leaking out.

It is safe to use suppositories during menstruation. Use menstrual pads instead of tampons, because a tampon could absorb some of the medication.

Read our guide to vaginal suppositories here.

Yeast infections are common in healthy adults. Researchers continue to look for treatments that have fewer side effects, better tolerability, and lower cost, while being highly effective.

A person can treat vaginal yeast infections with oral medicines, usually antifungals. These require a prescription. Other medications are available over the counter.

Boric acid is a common alternative treatment that doctors recommend if first-line treatment has not worked or if the infection recurs.

People with recurring vaginal yeast infections may benefit from using boric acid capsules. A doctor can advise about the best dosage and how long to use the medication.