What Is Plan B One-Step? Uses, Dosage, and What You Need to Know in 2026

Plan B One-Step is one of the most widely recognized over-the-counter medications in the United States — yet many people don't fully understand what it is, how it works, or when to use it. This guide provides a clear, fact-based overview of Plan B One-Step in 2026.

What Is Plan B One-Step?

Plan B One-Step is an emergency contraceptive pill — often called the morning-after pill — used to reduce the chance of pregnancy after unprotected sex or after another contraceptive method fails (such as a broken condom, missed birth control pills, or diaphragm displacement).

It contains levonorgestrel 1.5 mg — a synthetic progestin (a type of hormone) that has been used in birth control pills for more than 35 years. Plan B One-Step delivers a higher dose of levonorgestrel than daily birth control pills in a single tablet.

It is manufactured by Teva Pharmaceuticals and available over-the-counter (OTC) without a prescription at pharmacies, retailers, and many online sources.

Key Fast Facts About Plan B One-Step

Active ingredient: Levonorgestrel 1.5 mg

Drug class: Progestin-only emergency contraceptive

FDA-approved use: Prevention of pregnancy after unprotected sex or contraceptive failure

Prescription required: No — available OTC without age restriction since June 2013

Controlled substance: No

Efficacy: Reduces pregnancy risk by 75–89% when taken within 72 hours of unprotected sex

Time window: Most effective within 72 hours; can be taken up to 120 hours with reduced efficacy

Cash price: $45–$50 brand; $11–$45 for generics

What Is Plan B One-Step Used For?

Plan B One-Step has one FDA-approved indication: emergency contraception. It is used specifically in these situations:

After unprotected sex (no birth control was used)

After a contraceptive failure — broken or slipped condom, missed birth control pills, diaphragm displacement, birth control patch that came off, or NuvaRing that was expelled

After sexual assault (as an option to prevent pregnancy)

Plan B One-Step is not for routine use as a regular method of birth control. It is also not an abortion pill — it does not terminate an existing pregnancy.

How Do You Take Plan B One-Step?

Plan B One-Step is a single tablet taken orally. The instructions are simple:

Take one tablet (1.5 mg levonorgestrel) by mouth as soon as possible within 72 hours of unprotected sex — the sooner the better.

It can be taken with or without food, but taking it with food or water may help reduce nausea.

If you vomit within 2 hours of taking it, call a healthcare provider to ask about repeating the dose.

A clinical trial showed that Plan B One-Step reduced the expected pregnancy rate from about 8% to 1.1% after a single act of unprotected sex during the most fertile part of the menstrual cycle, when taken within 72 hours.

Who Should Not Use Plan B One-Step?

People who are already pregnant: Plan B will not work and is not indicated. It does not terminate an existing pregnancy.

People allergic to levonorgestrel: Check all ingredients on the package label if you have a known sensitivity.

People on certain medications: Rifampin, certain anti-seizure medications, efavirenz (HIV medication), and St. John's Wort can reduce Plan B's effectiveness significantly. Ask your pharmacist or doctor if you're on any of these.

People with BMI over 26–30: Levonorgestrel EC may be less effective at higher body weights. Consider ella or a copper IUD.

Generic Alternatives to Plan B One-Step

Many FDA-approved generic levonorgestrel 1.5 mg EC tablets are available OTC and work identically to Plan B One-Step: My Way, Take Action, Aftera, Next Choice One Dose, EContra EZ, Preventeza, AfterPill, and Opcicon One-Step. Generics typically cost $11–$40, compared to $45–$50 for Plan B One-Step brand.

To understand how Plan B works at the biological level, see our article on how Plan B One-Step works: mechanism of action explained.

If you're having trouble finding Plan B One-Step or a generic at a pharmacy near you, medfinder can help by contacting pharmacies in your area and texting you which ones have your medication available.