If you’ve found yourself Googling, “Plan B BMI limit, “Ella vs Plan B weight,” or “morning after pill 165 lbs,” you’re not alone. More and more people are searching for answers for one of the most common and widely misunderstood questions about the morning-after pill or emergency contraception (EC): Does body weight or body mass index (BMI) affect how well the medication works?
Want the short answer? Maybe a little bit, but not in the way you might be thinking.
Some research shows that certain EC pills, like Plan B and Morning After Pill, may be slightly less effective for people over a certain weight, but that doesn’t mean they stop working altogether. The morning-after pill is still safe, helps prevent pregnancy, and is worth taking when there’s a slip-up.
So, let’s break down what the science really says (without making your head spin) on the morning-after pill weight limit and discuss how to choose the most effective option for your lifestyle and reproductive health needs.
Does the Morning After Pill Work If You Weigh More?
Let’s just get straight to the point: Does the morning-after pill work if you weigh more?
Well, not to be the bearer of bad news, but there’s no simple “yes” or “no” answer; we have to dive into the science a bit to make more sense of it.
Some research, such as this study, found that the chance of getting pregnant increases significantly at a weight of 155 and beyond, with the pregnancy rate being 6.4% (a 1 in 15 chance) at 176 pounds. Organizations like Planned Parenthood state that ECs with levonorgestrel (like Plan B, Take Action, and Morning After Pill by Cadence OTC) may not be as effective if you weigh more than 165 pounds, and ulipristal acetate (Ella) won’t work as well if you weigh more than 195 pounds.
The theory is that the medication’s concentration in the body changes slightly as weight increases, which could make it less effective at stopping ovulation (aka preventing an egg from being released).
But this is what often gets lost in translation: less effectiveness doesn’t mean it’s totally ineffective.
There isn’t a specific Plan B BMI or weight limit at which it becomes completely unsafe or ineffective. It still lowers your chances of pregnancy, just not quite as much as it would for someone who weighs less.
If you weigh around 165 to 175 pounds, Plan B or similar brands may still work, with a slightly lower effectiveness rate, and that’s completely okay. Just remember that timing matters: the sooner you pop that pill after having unprotected sex, the better it works.
Think of it like this: emergency contraceptives might not be the perfect fit for everyone’s body, but they're still a solid option and always better than not taking anything to prevent pregnancy.
Learn more about which emergency contraception option is right for you.
Morning After Pill Weight Limits: What the Science Says
You may have come across a TikTok or two or doomscrolled through a Reddit thread warning that Plan B is no longer effective if you weigh 165 pounds or more. We understand that it can be pretty scary, but it’s not entirely accurate. As we’ve just discussed, there’s no specific weight cut-off at which EC suddenly decides not to work. Research suggests that the odds of pregnancy may be slightly higher, but not significantly so.
Walk with us through what the science and the U.S. Food and Drug Administration (FDA) actually said:
Plan B and Weight
- Some studies have found that Plan B’s effectiveness can decrease for individuals weighing more than 165 pounds or those with a BMI above 25.
- Other studies show less of a difference, which is why experts haven’t agreed on a strict cutoff.
- The FDA announced that it would not add a weight warning to Plan B’s label, saying there’s not enough evidence to prove a clear limit.
Ella and Weight
Alright, let’s talk about Ella (ulipristal acetate), which is another form of the morning-after pill that works a bit differently than Plan B and other levonorgestrel-based meds.
Ella tends to remain effective at higher weights compared to Plan B. Planned Parenthood reports that it may start to decline only at weights of 195 or more or BMI levels above 30, which is significantly higher than the threshold sometimes mentioned for Plan B.
So what’s the catch? Ella is a prescription-only medication available in the United States. You can’t just make a run to the convenience store or pharmacy and snatch it up like you can with Plan B. But you can get it through telehealth or certain online pharmacies.
In short: if you weigh more than 165 pounds and want extra reassurance, Ella is typically the better choice (if you can get it quickly enough).
Why Research is Complicated
It’s clear that there’s no set weight limit to use EC, so what’s all the hubbub about?
Here’s why researchers and healthcare providers can’t seem to give a straight answer about the relationship between EC effectiveness and body weight:
- Many studies had small sample sizes, meaning that only a limited number of participants fell within higher weight ranges.
- There are no standard definitions of “overweight” or “obese” across studies, so the research doesn’t always match up.
- The timing of EC matters a lot, but not all studies tracked it consistently.
The TL;DR? The research is somewhat helpful, but it doesn’t provide the definitive answers we’re looking for.
It’s fair to say that weight may play a role in how effective EC pills are, but it’s also fair to say that Plan B still helps prevent pregnancy for people of all sizes.
Plan B Effectiveness by Weight and BMI
Let’s dive a bit deeper into what these numbers actually mean, since most of us aren’t thinking in terms of BMI spreadsheets.
If you’ve ever searched “Plan B 165 lbs” or Plan B BMI limit,” you’re likely trying to figure out what these cutoffs mean in real life.
Here’s what you should know:
- Plan B weight limit: There’s no official limit. Neither the brand nor the FDA has set one.
- Plan B BMI limit: No labeled limit, but some research suggests that the pill becomes less effective above a BMI of 25.
- Does Plan B work at 165 lbs? Yes. Studies suggest that it may be slightly less effective.
Still a bit confused? Just think of it like sunscreen: if you apply less than the recommended amount, it still protects you, it just won’t be as strong as it could be. It’s the same thing for emergency contraceptive pills.
FYI: If you’re within that 165-175 (or 195 or higher for Ella) range, take that Plan B ASAP. It will work best within 72 hours (or up to five days on Ella), and the sooner, the better. Then, if you want more peace of mind next time, hit up your healthcare provider about a copper IUD as a backup option.
Order the Morning After Pill from Cadence OTC today.
Emergency Contraception Options for Overweight Women
Still worried about the effectiveness of emergency contraception for overweight or obese women? Don’t fret, we’ve got you covered. The good news is that there are a few options to explore.
Here’s a brief rundown of your main emergency contraception choices, and how they stack up.
Plan B, Take Action, and Morning After Pill by Cadence OTC (levonorgestrel)
- Best for: Individuals weighing under 165 lbs or those requiring immediate EC.
- Availability: Over the counter, no prescription or doctor’s visit needed.
- Effectiveness: May drop slightly for folks over 165 lbs, but still worth taking.
- Timing: Works best within 72 hours after having unprotected sex.
Ella (ulipristal acetate)
- Best for: Individuals weighing over 195 lbs or with a BMI above 35.
- Availability: Prescription-only in the U.S., but available via telehealth services.
- Effectiveness: May be more reliable at higher weights. Effectiveness may decrease slightly above 195 pounds or 35 BMI.
- Timing: Works up to five days after unprotected sex, but it's still best to use it as soon as you can get it
Discover how Ella and other alternatives compare.
Copper IUD (ParaGard)
- Best for: Anyone, regardless of weight or BMI, who desires the most effective long-term EC option available.
- Availability: Requires a prescription and a medical procedure from a healthcare provider.
- Effectiveness: Over 99% effective at preventing pregnancy, no matter your size.
- Timing: Once inserted, it doubles as long-term birth control that works for up to 10 years.
Not sure what option is best for your lifestyle and reproductive health? Check out our guide on the 10 things you should know about the morning-after pill to get a breakdown of how each one works.
FAQs: Weight and Emergency Contraception
Let’s address some of the most frequently asked questions about weight and EC, as there’s a lot of confusion surrounding this topic.
Does the morning-after pill cause abortion?
Morning After Pill does not cause an abortion. They actually work by delaying ovulation (so there’s no egg to fertilize). If you’re already pregnant, these pills won’t affect it.
What if I weigh 165 lbs?
You’re right at the limit where research suggests that Morning After Pill effectiveness may dip slightly. It can still work, especially if taken quickly, but you may want to consider Ella or a copper IUD for added protection.
Is Ella better than Plan B if I’m overweight?
In most instances, yes. Ella tends to be more effective at higher weights, although it may still be less effective above 195 pounds or in females with a BMI of 35.
Should I still take Plan B if I’m concerned about it?
Absolutely. Taking Plan B is always better than taking nothing at all. Even if its effectiveness drops a little bit, it still significantly lowers your risk of pregnancy.
Why Transparency About Weight and Efficacy Matters
Let’s be real, talking about weight in the context of emergency contraception can be very uncomfortable. But what’s not uncomfortable is having the research evidence that helps you make better choices for your body and reproductive health.
Transparency is important because it:
- Helps people prepare -having trusted information is powerful
- Acknowledges that bodies are different, and that’s okay.
- Encourages proactive planning, like keeping EC in your nightstand or knowing what’s available at your nearest pharmacy or convenience store.
At Cadence OTC, we believe that information should be empowering, not intimidating. That’s why we strive to be a trustworthy source that delivers accurate health education. In our view, there is no time for shame, stigma, or scare tactics.
Want to learn more? Check out our Learn & Share blog for guides on when to take the morning-after pill, keeping emergency contraceptives on hand, and other resources to help you make confident, informed decisions about your reproductive health.
Conclusion
The bottom line? Your body weight can influence how well some morning-after pills work, but that doesn’t mean they stop working altogether. If one doesn’t suit you, there are other options, and they all offer pregnancy prevention.
While Morning After Pill may be slightly less effective at higher weights, it remains a safe and helpful option. Ella tends to work better for folks with higher weights, but has a lower effectiveness rate at a BMI above 35. Copper IUDs, on the other hand, are the gold standard for everyone, regardless of weight.
So, whether you’re 150, 165, or over 200, know that you’ve got reliable emergency contraception choices that can fit your body and your life.
Find the emergency contraception option that’s right for you at Cadence OTC.
