Phexx Side Effects: What You Should Know

Phexx (Lactic Acid, Citric Acid, and Potassium Bitartrate vaginal gel) is a non-hormonal contraceptive that works by maintaining your vaginal pH. Like all medications, it can cause side effects. Most are mild and go away on their own, but some need medical attention.

This guide covers the most common and serious side effects reported in clinical trials, who may be more at risk, and when you should contact your healthcare provider.

What Is Phexx?

Phexx is an on-demand vaginal contraceptive gel made by Evofem Biosciences. You insert one pre-filled applicator (5 grams) vaginally before intercourse. It works by keeping vaginal pH in the 3.5–4.5 range, which limits sperm movement. Because it's non-hormonal, it doesn't cause the systemic side effects associated with birth control pills, patches, or hormonal IUDs.

Common Side Effects

The following side effects were reported in clinical trials. Most are localized to the vaginal area and tend to be mild to moderate:

• Vulvovaginal burning sensation — 18.0% of users
• Vulvovaginal itching (pruritus) — 14.5% of users
• Yeast infection (vulvovaginal mycotic infection) — 9.1% of users
• Urinary tract infection (UTI) — 9.0% of users
• Vulvovaginal discomfort — 9.0% of users
• Bacterial vaginosis — 8.4% of users
• Vaginal discharge — 5.5% of users
• Genital discomfort — 4.1% of users
• Painful urination (dysuria) — 3.1% of users
• Vulvovaginal pain — 2.1% of users

Male Partner Side Effects

Partners may also experience local reactions. In clinical trials, 9.8% of male partners reported burning, itching, or pain in the genital area after intercourse with a Phexx user. These symptoms are typically mild and resolve quickly.

Serious Side Effects

Serious side effects from Phexx are rare, but they do happen:

• Cystitis and pyelonephritis (kidney infection) — Occurred in 0.36% of clinical trial participants. One serious case required hospitalization. This is why Phexx is not recommended for people with a history of recurrent UTIs or urinary tract abnormalities.
• Hypersensitivity reaction — Rare allergic reactions have been reported. If you experience swelling, difficulty breathing, or severe rash after using Phexx, seek emergency medical care.

Phexx does not carry a boxed warning (the most serious type of FDA warning).

Who May Be More at Risk for Side Effects?

People With a History of Recurrent UTIs

Phexx is contraindicated — meaning it should not be used — in people who have a history of recurrent urinary tract infections or urinary tract abnormalities. The acidic ingredients in Phexx may irritate the urinary tract and increase the risk of UTIs and more serious kidney infections.

Pregnant People

Phexx is a contraceptive and is not intended for use during pregnancy. If you become pregnant while using Phexx, stop using it and contact your doctor.

Breastfeeding

There is no data on whether Phexx's ingredients pass into breast milk. Talk to your doctor about the risks and benefits if you are breastfeeding.

People With Allergies to Ingredients

If you have a known hypersensitivity to Lactic Acid, Citric Acid, Potassium Bitartrate, or any of the inactive ingredients in Phexx, do not use this product.

How to Manage Common Side Effects

If you experience mild side effects, these tips may help:

• Burning or itching — This often improves with continued use as your body adjusts. If it persists beyond a few uses or is severe, talk to your doctor.
• Yeast infections — Over-the-counter antifungal treatments (like Miconazole) can help. If yeast infections become recurrent, your doctor may suggest an alternative contraceptive.
• UTIs — Stay hydrated, urinate after intercourse, and contact your doctor if you develop symptoms like frequent urination, burning during urination, or lower abdominal pain.
• Vaginal discharge — Some discharge is normal after using a vaginal gel. If it becomes foul-smelling, changes color, or is accompanied by itching, see your doctor to rule out bacterial vaginosis.
• Partner discomfort — If your partner experiences irritation, it usually resolves quickly. Washing the area after intercourse may help.

When to Call Your Doctor

Contact your healthcare provider if you experience:

• Side effects that don't go away or get worse over time
• Signs of a UTI — burning during urination, frequent urge to urinate, cloudy or bloody urine
• Signs of a kidney infection — fever, chills, back or side pain, nausea
• Signs of an allergic reaction — hives, swelling, difficulty breathing
• Recurrent yeast infections or bacterial vaginosis

Final Thoughts

Most side effects from Phexx are mild and localized — burning, itching, and discomfort are the most common. Serious side effects like kidney infections are rare but can happen, especially in people with a history of recurrent UTIs.

If you're considering Phexx, talk to your doctor about whether it's a good fit for your health history. And if you're ready to fill your prescription, use Medfinder to find a pharmacy with Phexx in stock near you.