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Phexx

lactic acid / citric acid / potassium bitartrate
Used for Birth Control

Phexx is a hormone-free prescription birth control used to help prevent pregnancy. It's a vaginal gel that contains three ingredients: lactic acid, citric acid, and potassium bitartrate. Though it’s not a spermicide, you use it in the same way — by inserting it into the vagina before sex, as needed. Common side effects include vaginal burning, itching, and yeast infections.

Reviewed by:Last reviewed on July 23, 2026
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What is Phexx?

What is Phexx used for?

How Phexx works

Phexx is a vaginal pH regulator. It works by making the vagina more acidic during sex. This makes it harder for sperm to move and reach an egg, which lowers your risk of pregnancy.

Drug facts

Common BrandsPhexx
Drug ClassContraceptive
Controlled Substance ClassificationNot a controlled medication
Generic StatusNo lower-cost generic available
AvailabilityPrescription only
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Side effects of Phexx

The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.

Common Side Effects

  • Vaginal burning (18%)
  • Vaginal itching (15%)
  • Vaginal yeast infection (9%)
  • Urinary tract infection (UTI) (9%)
  • Vaginal discomfort (9%)
  • Vaginal bacterial infection (8%)
  • Vaginal discharge (6%)

Less Common Side Effects

  • Genital discomfort
  • Painful urination
  • Vaginal pain

Phexx serious side effects

Contact your healthcare provider immediately if you experience any of the following.

  • Bladder and kidney infection: pain or burning during urination, cloudy urine, pain in the pelvis, back pain
  • Allergic reactions: burning or stinging, itching, redness, swelling, pain, rashes, sores

Source: DailyMed

The following Phexx side effects have also been reported

Side effects that you should report to your care team as soon as possible:

Side effects that usually do not require medical attention (report these to your care team if they continue or are bothersome):

  • Vaginal irritation at application site
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Avg retail price
$463.46(Save 20.06%)
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$370.49
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Pros and cons of Phexx

Pros

  • A hormone-free birth control option
  • Used only as needed right before (or up to 1 hour before) vaginal sex
  • Can be used anytime, even during your period

Cons

  • Must be prescribed by a healthcare professional
  • Can cause vaginal burning, itching, or discomfort
  • Doesn't work as well to prevent pregnancy as some other birth control methods
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Pharmacist tips for Phexx

pharmacist
  • Use Phexx right before or up to 1 hour before vaginal sex. Use a new applicator every time you have vaginal sex, even if it’s within the same hour.
  • You can use Phexx at any time, including while you’re on your period.
  • You can use Phexx if you have a vaginal infection. It’s also safe to use with vaginal medications like miconazole, metronidazole, and tioconazole.
  • You can use Phexx with hormonal birth control, condoms, and diaphragms. Just don't use it with a vaginal ring.
  • It’s okay to use Phexx after childbirth, an abortion, or a miscarriage once your OB-GYN says it’s safe to have vaginal sex.
  • Phexx doesn’t protect against HIV and other sexually transmitted infections (STIs). Talk to your prescriber if you have questions about ways to protect yourself from these infections.
  • Tell your prescriber if you have symptoms of a urinary tract infection (UTI) while using Phexx. Symptoms can include burning when you urinate, fever, or back pain.
  • Phexx can cause vaginal burning, itching, or discomfort. These side effects can also happen to your partner, so let your prescriber know if they become bothersome.
  • Pregnancy: Stop using Phexx if you become pregnant. It's only used to help prevent pregnancy.

How to use Phexx:

  • Read the Instructions For Use before using Phexx to make sure you use it correctly.
  • Remove the applicator and plunger from the foil package. Insert the plunger into the applicator and remove the pink cap.
  • Gently insert the applicator into your vagina. Then, using your index finger, push the plunger all the way down. Remove the applicator and plunger, and throw them away.
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Risks and warnings for Phexx

Phexx can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.

Urinary tract infections

  • Risk factors: Repeated urinary tract infections (UTI) | Other urinary tract conditions

Phexx can raise your risk of urinary tract infections (UTIs), including bladder and kidney infections. Your risk is higher if you've had UTIs before or have other urinary tract conditions. Even though UTIs are common, they can be serious if left untreated.

Tell your prescriber if you have symptoms of a UTI, such as pain or burning when you urinate, cloudy urine, pelvic pain, or back pain. UTIs can become serious if they aren't treated, so you might need antibiotics.

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Phexx dosage

The average cost for 1 box of twelve 5g applicators of 1.8%/1%/0.4% of Phexx is $370.49 with a free GoodRx coupon. This is 20.06% off the average retail price of $463.46.
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DosageQuantityPrice as low asPrice per unit
twelve 5g applicators of 1.8%/1%/0.4%1 box$370.49$370.49
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How much does Phexx cost?

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What are alternatives to Phexx?

There are a number of medications that your doctor can prescribe in place of Phexx. Compare a few possible alternatives below.
Phexx
Used for:
$370.49Lowest GoodRx priceView prices
Used for:
  • To prevent pregnancy
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News about Phexx

References

Best studies we found

Belyayeva, M., et al. (2024). Acute pyelonephritis. StatPearls.

Evofem, Inc. (2025). PHEXX- lactic acid, l-, citric acid monohydrate, and potassium bitartrate gel [package insert]. DailyMed.

Planned Parenthood Federation of America. (n.d.). Phexxi.

GoodRx Health has strict sourcing policies and relies on primary sources such as medical organizations, governmental agencies, academic institutions, and peer-reviewed scientific journals. Learn more about how we ensure our content is accurate, thorough, and unbiased by reading our editorial guidelines.