Aftera is essentially the same as Plan B One-Step. Both contain the same active ingredient, levonorgestrel, at the same dose of 1.5 mg. Aftera is a generic version of Plan B, and the two work identically in your body. The only real differences are the brand name on the box and the price you pay at the register.
Same Ingredient, Same Dose
Both Aftera and Plan B One-Step are single-tablet emergency contraceptives containing 1.5 mg of levonorgestrel, a synthetic form of progesterone. Cleveland Clinic lists Aftera alongside Plan B One-Step, My Choice, Option 2, Take Action, and Preventeza as levonorgestrel brands that “all work the same way.” There is no difference in formulation that would make one more effective or safer than the other.
How They Prevent Pregnancy
Levonorgestrel works primarily by delaying or preventing ovulation. If your body hasn’t released an egg yet, the hormone keeps that from happening, so sperm have nothing to fertilize. It does not end an existing pregnancy.
The pill is most effective when taken as soon as possible after unprotected sex. Studies show a pregnancy rate of roughly 1.2% to 2.1% when levonorgestrel is taken within 72 hours. The WHO notes that emergency contraception can prevent over 95% of pregnancies when used within five days, though effectiveness drops with every hour you wait. For levonorgestrel specifically, the three-day (72-hour) window is the recommended cutoff.
The Price Difference
This is where choosing between the two actually matters. Plan B One-Step typically costs between $38 and $44 at retail pharmacies. Aftera and other generics are generally cheaper, sometimes by $10 to $20 depending on the store. Both are available over the counter with no age restriction and no prescription required. If you’re standing in a pharmacy aisle deciding between them, the lower-priced option will give you the same result.
Side Effects
Because the active ingredient is identical, side effects are the same regardless of which brand you take. The most common ones include nausea, headache, fatigue, breast tenderness, abdominal cramping, and dizziness. Your next period may come earlier or later than expected, and you might notice light spotting in the days after taking the pill.
These effects are mild for most people and resolve within a few days. If you vomit within a couple of hours of taking the tablet, the dose may not have been fully absorbed, and you may need to take another one. Heavy bleeding with stomach pain or ongoing irregular bleeding are signs worth calling a healthcare provider about.
Weight Can Affect Effectiveness
One important factor that applies equally to Aftera, Plan B, and every other levonorgestrel emergency contraceptive: body weight can reduce how well the pill works. Clinical guidelines from the Faculty of Sexual and Reproductive Healthcare indicate that levonorgestrel emergency contraception becomes less effective in people with a BMI above 26 or a body weight over about 155 pounds (70 kg). This doesn’t mean it won’t work at all, but the failure rate goes up.
If you’re above that weight threshold, a different type of emergency contraceptive containing ulipristal acetate may be more effective, though it requires a prescription in the U.S. A copper IUD inserted within five days is also an option and is the most effective form of emergency contraception at any weight. Your pharmacist or provider can help you decide.
How to Choose Between Them
If you’re picking between Aftera and Plan B at the pharmacy, buy whichever is available and affordable. They contain the same drug at the same strength, carry the same side effects, and work on the same timeline. Generic medications in the U.S. must meet the same FDA standards for quality, safety, and performance as their brand-name counterparts. Paying more for Plan B does not buy you better protection.
The most important variable isn’t which brand you choose. It’s how quickly you take it. Every hour counts, so grab whichever box is in front of you and take it right away.