Off-brand Plan B contains the same active ingredient, in the same dose, and works the same way as the brand-name version. Every generic levonorgestrel emergency contraceptive sold in the United States contains 1.5 mg of levonorgestrel in a single tablet, which is identical to what’s in Plan B One-Step. The FDA requires generic versions to prove they deliver the drug into your bloodstream at the same rate and concentration as the original.
What the FDA Requires From Generics
To earn FDA approval, a generic emergency contraceptive must pass a bioequivalence study. This means the manufacturer runs a clinical comparison in which healthy volunteers take the generic pill and the brand-name pill in separate periods, and researchers measure levonorgestrel levels in their blood. The generic must produce plasma concentrations that fall within a tight statistical window (a 90% confidence interval) of the brand-name product. If the drug doesn’t hit that mark, it doesn’t get approved.
The FDA also requires comparative dissolution testing, which measures how quickly the tablet breaks apart and releases its active ingredient. For the 0.75 mg strength (an older two-pill regimen), manufacturers can skip the full blood-level study if their 1.5 mg version already passed and both strengths dissolve at comparable rates. The bottom line: a generic that’s on a U.S. pharmacy shelf has already demonstrated it performs the same way in your body as Plan B One-Step.
Common Generic Names You’ll See
Several off-brand options are widely available, including Take Action, My Way, New Day, Aftera, AfterPill, EContra EZ, Fallback Solo, and Option 2. All of these contain levonorgestrel 1.5 mg in a single tablet. The packaging may look different and the inactive ingredients (binders, fillers, coatings) can vary slightly between brands. If you have a known allergy to a specific dye or filler, check the inactive ingredient list on the box, but for most people this difference is irrelevant.
How They All Work
Levonorgestrel, whether brand or generic, works primarily by delaying or preventing ovulation. If your body hasn’t released an egg yet, the pill can pause that process long enough for sperm to die off. It does not end an existing pregnancy. The pill is most effective within the first 24 hours after unprotected sex, and effectiveness declines over time. Taken within three days (72 hours), levonorgestrel emergency contraception is roughly 81 to 90% effective at preventing pregnancy. You can still take it up to five days (120 hours) afterward, but it becomes less reliable the longer you wait.
Side Effects Are the Same
Because the active ingredient and dose are identical, the side effect profile doesn’t change between brand and generic. In clinical trials of the 1.5 mg levonorgestrel tablet, the most commonly reported effects were:
- Heavier menstrual bleeding: 30.9%
- Nausea: 13.7%
- Lower abdominal pain: 13.3%
- Fatigue: 13.3%
- Headache: 10.3%
- Dizziness: 9.6%
- Breast tenderness: 8.2%
- Delayed period (more than 7 days): 4.5%
These numbers apply regardless of which brand you take. If your next period is more than a week late, a pregnancy test is a reasonable next step.
The Price Difference Is Real
The biggest practical difference between Plan B One-Step and its generics is cost. Brand-name Plan B typically runs $35 to $50 at retail pharmacies. Generic versions often sit on the same shelf for $10 to $25. Online retailers sometimes carry generics for even less. If you’re getting emergency contraception at a clinic like Planned Parenthood, pricing may be on a sliding scale. There is no clinical reason to pay more for the brand name.
Weight Can Affect Effectiveness
One factor that matters more than brand choice is body weight. Research published in the journal Contraception found that levonorgestrel emergency contraception becomes significantly less effective as weight increases. Women weighing between 65 and 75 kg (about 143 to 165 lbs) had an estimated pregnancy rate of 1.4%. That rate jumped to roughly 6% for women weighing 75 to 85 kg (165 to 187 lbs), a level approaching what you’d expect without any contraception at all. Statistical modeling showed a steep increase in pregnancy risk starting around 70 to 75 kg.
This limitation applies equally to Plan B One-Step and every generic. If you weigh over 165 pounds, a copper IUD or a different emergency contraceptive pill containing ulipristal acetate (sold as ella) may be more effective options. Ulipristal acetate requires a prescription but maintains effectiveness at higher body weights and works up to five days after unprotected sex.
No Age Restriction for Any Version
Both brand-name and generic levonorgestrel emergency contraception are available over the counter in the United States with no age restriction. You do not need a prescription or ID. They’re typically stocked in the family planning aisle, though some stores keep them behind the pharmacy counter or in a locked case. If you don’t see them on the shelf, ask a pharmacist. They cannot legally refuse to sell them based on your age.