Ella vs. Plan B: Which Morning-After Pill Works Best for You (Including If You Weigh Over 165 lbs)
If you need emergency contraception, ella (ulipristal acetate) is the more effective pill overall — it maintains stronger effectiveness for up to 120 hours and holds up better at higher body weights. Plan B (levonorgestrel) is widely available over the counter and works well when taken within 24 hours, but its effectiveness drops significantly after 48 hours and may be reduced if you weigh more than 165 pounds. If you weigh over 195 pounds, neither pill is as reliable as a copper IUD, which is the most effective emergency contraception option regardless of body weight.
What is the difference between ella and Plan B?
Both ella and Plan B prevent pregnancy after unprotected sex or contraceptive failure — a broken condom, a missed pill, or unprotected intercourse. They are not the same drug, and the differences between them matter for choosing the right option for your situation.
Plan B One-Step (and its generics, such as Take Action, My Way, and Next Choice) contains levonorgestrel, a synthetic progestin. It works primarily by delaying or preventing ovulation. Plan B is available over the counter without a prescription and has been approved by the FDA since 1999. It is most effective when taken within 24 hours of unprotected sex (up to 95% effective at that window) and is approved for use up to 72 hours afterward, though effectiveness drops to around 61% at the 48–72-hour mark, according to FDA labeling.
ella (ulipristal acetate 30 mg) is a selective progesterone receptor modulator — a different class of drug entirely. It delays or inhibits ovulation and may also affect how the uterine lining responds to implantation. Ella requires a prescription, which you can obtain online through a telehealth provider. It is approved for use up to 120 hours (five days) after unprotected sex and maintains its effectiveness more evenly across that entire window: clinical trial data published in The Lancet showed ella reduced pregnancy risk by approximately 65% compared to placebo, versus 52% for levonorgestrel, when taken within 120 hours.
Does emergency contraception work if you weigh over 165 pounds?
This is one of the most important — and most underappreciated — questions about emergency contraception. The short answer: weight matters, and your options change as weight increases.
Research has consistently found that levonorgestrel-based pills like Plan B become less effective at higher body weights. A 2011 analysis in Contraception (and later reinforced by a 2014 European Medicines Agency review) found that individuals with a BMI above 25 kg/m² had a meaningfully higher failure rate with levonorgestrel EC, and that individuals with obesity (BMI ≥30) were roughly three times more likely to become pregnant after taking Plan B compared to those with a normal BMI. The FDA label for Plan B does not set a formal weight cutoff, but clinical guidance broadly recognizes that effectiveness is reduced above approximately 165–175 pounds in people of average height.
Ella performs better at higher weights. Studies suggest ella maintains effectiveness up to a BMI of approximately 35 kg/m², which corresponds to roughly 195 pounds for someone who is 5’5”. Above that threshold, ella’s effectiveness also begins to decline.
For individuals who weigh more than 195 pounds or have a BMI above 35, the copper IUD (Paragard) inserted within 120 hours is the recommended option. The American College of Obstetricians and Gynecologists (ACOG) explicitly states that the copper IUD is the preferred emergency contraception for patients with obesity and those who want the most reliable protection regardless of weight. The copper IUD achieves a pregnancy rate of less than 0.1% — greater than 99% effective — and weight has no effect on its mechanism of action.
How long does each morning-after pill work?
| Option | Window | Effectiveness (when taken on time) | Prescription? | Weight concern |
|---|---|---|---|---|
| Plan B / levonorgestrel | Up to 72 hours | ~95% at <24h; ~61% at 48–72h | No (OTC) | Reduced above ~165 lbs |
| ella / ulipristal acetate | Up to 120 hours | ~85% across full 5-day window | Yes | Reduced above ~195 lbs |
| Copper IUD (Paragard) | Up to 120 hours | >99% | Provider insertion required | Not affected by weight |
The timing window is where ella’s advantage is clearest. Plan B’s labeling notes declining effectiveness after 72 hours, while ella maintains roughly the same effectiveness on day five as it does on day one. If you are approaching or beyond the 72-hour mark, ella is the significantly stronger oral option.
Can you take ella and Plan B together, or one after the other?
No — and this is a critical safety point. Do not take ella and Plan B together or in close succession. Because ella is a progesterone receptor modulator and Plan B is a progestin, they work in opposite ways on the same receptors. Taking levonorgestrel after ella can block ella’s mechanism and reduce its effectiveness, according to FDA guidance. Choose one option based on your timing and weight, and do not combine them.
Can you get ella online without going to a pharmacy?
Yes. Because ella requires a prescription, you cannot buy it at a pharmacy counter the way you can Plan B. However, licensed telehealth providers can prescribe ella after a brief consultation — often within 30 to 60 minutes — and many pharmacies will fill it same-day, or it can be sent via express shipping. Same-day or next-day access through telehealth can be faster than locating an in-stock pharmacy in your area, particularly in rural communities or on weekends.
When requesting ella online, be prepared to share:
- When unprotected sex occurred (date and time if possible)
- Current medications, particularly hormonal birth control (see interaction note below)
- Approximate weight and any relevant health history
Important interaction note: If you are currently taking hormonal birth control — particularly progestin-based methods — ella’s effectiveness may be reduced. If you use the progestin-only minipill, implant, or hormonal IUD, discuss this with your telehealth provider before taking ella. Barrier methods (condoms) and non-hormonal IUDs do not interact with ella.
What should you do after taking emergency contraception?
Regardless of which option you choose:
- Take it as soon as possible. Every hour counts — both ella and Plan B work best the sooner they are taken.
- Watch for a normal period. Your next period may arrive a few days early or late after either pill. If your period is more than a week late, take a pregnancy test.
- Consider ongoing birth control. Emergency contraception is not intended for routine use. After your period arrives, talk to a provider about a consistent method — hormonal pills, an IUD, an implant, or other options — to prevent the need for emergency contraception in the future.
- Seek STI testing if relevant. Emergency contraception does not protect against sexually transmitted infections. If there was a risk of STI exposure, consider testing.
Frequently Asked Questions
Does Plan B work if I’ve already ovulated? Plan B works primarily by delaying ovulation. If you have already ovulated at the time you take it, its effectiveness is substantially lower. This is one reason taking it as early as possible — before the ovulation window — matters. Ella may have a slightly longer window of ovulation suppression, but neither pill is reliable after ovulation has occurred. The copper IUD can prevent implantation and is more effective post-ovulation.
Will taking ella or Plan B affect my future fertility? No. Neither levonorgestrel nor ulipristal acetate has any effect on your long-term fertility. Emergency contraception works by delaying or preventing ovulation in a single cycle; it does not affect your ovaries, eggs, or ability to become pregnant in subsequent cycles.
Can I use ella if I am breastfeeding? The FDA advises that breastfeeding individuals pump and discard breast milk for 36 hours after taking ella, as ulipristal acetate transfers into breast milk. Plan B (levonorgestrel) is generally considered compatible with breastfeeding, though some guidelines suggest discarding milk for 8 hours as a precaution. Discuss your situation with your provider.
Does ella work if I weigh 175 pounds? At 175 pounds, ella is still considered your best oral option — it is meaningfully more effective than Plan B at that weight. The evidence suggests ella maintains reasonable effectiveness up to approximately 195 pounds or a BMI of about 35. If you have concerns, a telehealth provider can help you assess whether ella or a copper IUD is the better choice for your situation.
How quickly can I get ella through telehealth? Most people receive a prescription within an hour of completing a telehealth consultation. With a same-day prescription sent to a local pharmacy, you can often have the medication in hand within two to four hours. Because the clock starts the moment unprotected sex occurred, initiating the consult immediately — rather than waiting to see if a period arrives — gives you the best chance of getting ella within its most effective window.
Time-sensitive decisions deserve time-sensitive care. If you need emergency contraception — especially ella, which requires a prescription — Omnia TeleHealth’s emergency contraception service connects you with a licensed provider quickly, so you can make an informed choice and get treated before the window closes. Same-day consultations are available seven days a week.