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How Long Does Plan B Stay In Your System After You Take It?

The day before Valentine’s day – all those feelings, rugged breathings, and some crazy moments – time and space stopped for a while! However, moments later, a bolt out of the blue – no condoms!

Well, like every other girl after unprotected intercourse, I went for the suitable silver bullet- Plan B. But, now, questions are popping out, making me panicky- will it work? How long does plan b stay in your system?

Plan B stays in your body for around 5 to 7 days after taking it. It contains the synthetic hormone progesterone, levonorgestrel, which you must take within 72 hours after unprotected intercourse. The hormone usually absorbs into your bloodstream within hours, but you may face some side effects.

Stay with us to learn more about Plan B, its lifespan, effectiveness, side effects, and many more.

It mainly depends on the elimination half-life of Levonorgestrel, which is mostly 24.4 hours. That means the hormone should leave your body around the end of the 5th day.

Table of Content

How Long Does Plan B Stay In Your System?

Accidents happen: that’s why you have Plan B.

When you have unplanned, unprotected, or accidental (leaked, torn, or broken condom) intercourse, where pregnancy is not desirable, you usually use emergency contraceptives.

So, what are these pills? Plan B is usually a synthetic hormone, Levonorgestrel. After you take the pill, it soon resolves in your bloodstream and starts action – preventing your pregnancy. It stops an egg’s release from your ovary or the connection between a fertilized egg and your uterus.


Now, you may ask, after taking the pill, how long will they be effective, or how long will they be in your system?

Usually, in most women, the synthetic hormone clears out within 5 days. It’s also the time that sperm can live inside your reproductive tract.

But, it mainly depends on the elimination half-life of Levonorgestrel, which is mostly 24.4 hours. That means the hormone should leave your body around the end of the 5th day.

However, researchers also found that it may vary from person to person, as in, it shows the half-life of 19 to 29 hours. That means the hormone can be cleared from your body from the earliest 4.3 days to the longest, 12 days.

But, in most cases, the synthetic hormone takes approximately a week to eliminate from your system after a single ingestion.

5 Reasons Plan B Is Still in Your System

Plan B, in most women, is effective for 5 days, and then its power falls. However, it can stay in your system for 7 days or more. Now, why do the days vary?

Well, several factors can impact why the hormone is still lingering in your body. So, let’s learn about those influencers.


How often do you take Plan B – to be precise, do you take them every night, weekly, or only in an emergency?

How long Plan B stays in your system depends on how frequently you take the pills.

For example, if you take Plan B One Step only when emergencies occur, it will take less time to eliminate from your body. On the other hand, if you take the pills more often – let’s say daily or weekly – the hormone most likely lingers in your body for a bit longer.


The reason is that the frequent use of this pill increases levonorgestrel accretion in your tissues. Moreover, your hepatic metabolism will be weaker, unable to eliminate the hormone circulating in your system.


We have already talked about frequency; now, let’s discuss the dosage. Yes, like frequency, the dosage can impact the lifespan of Plan B in your system.

Like all medicines, the more you take a pill, the more days it will stay in your body.

Plan B One-Step is a single-shot pill: you only take one. It usually contains 1.5 milligrams of levonorgestrel: a lower dose.

Usually, after taking a single shot lower dose, it washes off your system within 5 days. However, if you take multiple pills or more than sooner after taking one, the synthetic hormone will stay in your body for longer.

Health and Medication

Your health conditions or medications can impact the lifespan of levonorgestrel in your system. Let’s just say – your liver, kidney, and metabolism.

Unhealthy liver – your Hepatic functions impact Plan B’s stay in your system. The liver helps in drug clearance. If you have a compromised liver function – impairment, dysfunction, or disease – the synthetic hormone will stay in your body longer than usual.

Unhealthy Kidney – Renal impairment can slow your body’s excretion of Plan B from your system. Your compromised kidney will not work efficiently discharging the drug.

Poor Metabolism – If you have a low metabolic rate, your body will burn less energy, leading to a slower metabolism. In addition, it will also exhibit poor efficiency in exogenous substance elimination. Therefore, you have an elevated amount of levonorgestrel in your system.

Medications – CYP450 isoenzymes are usually responsible for metabolizing the primary Plan B component levonorgestrel. So, if you’re taking any medicines, which are CYP450 inhibitors, Plan B will stay in your system for longer. These inhibitors include Ritonavir, Ciprofloxacin, Enoxacin, Fluvoxamine, etc.


We know that CYP450 isoenzymes influence the metabolism of Plan B. But what actually is CYP?

CYP or Cytochrome P450 is one superfamily of hemeproteins. It is usually located within the endoplasmic reticulum and liver cells. They play a crucial role in your body – oxidize steroids, fatty acids, and xenobiotics; eliminate and break down various compounds, drugs, toxins, and hormone synthesis.

The study showed that alleles of CYP genes might vary in person, affecting the metabolism. So, if you have a decreased CYP450 function, your body will eliminate levonorgestrel slowly as it will have a longer half-life.

However, more research is needed concerning this topic.

Body Weight

However, not in a significant part; your body weight may impact the cleansing of Plan B from your system.

Levonorgestrel is extremely lipophilic. That means it absorbs into your system quickly, also in fat. That’s why it’s a popular choice among obese.

A study showed that clearance of cytochrome P450 (CYP) 3A4 substrates is lower in obese than non-obese.

So, if you have increased body weight, Plan B will likely take more time to cleanse from your system as levonorgestrel remains in fat for longer. On the other hand, if you have a low BMI, the hormone will excrete as soon as less fat will be there to retain them.

How to Clear Plan B From Your System Quickly?

Plan B usually stays 5 to 7 days in your system. However, if you want to eliminate the synthetic hormone sooner, you can apply some ways.

However, it’s wise to consult your physician before going for any strategies imposing risks or issues.

Diet Modification

A healthy diet is always beneficial for you, even for drug clearance. Several foods delay gastric emptying time, alter gastrointestinal pH, stimulate bile flow, and increase splanchnic blood flow, helping drug elimination—for example, rich protein food, vegetables, fruit, teas, etc.

As obesity interferes with levonorgestrel elimination, you can avoid food that may increase your weight. You can opt for a low-carb diet.


In addition, the study suggested that acidified urine can help eliminate levonorgestrel from your system. So, you can increase acidic food intake to acidify your urine. These foods include-

  • Vegetables – corn, white beans, lentils, etc.
  • Fruits – prunes, plums, and cranberries.
  • Plenty of Protein – beef, poultry, fish, eggs, nuts, etc.
  • Carbs – rice, pasta, cereal, bread, etc.
  • Dairy – milk, cheese, or creme.
  • Betaine – beets, broccoli, wheat bran, spinach, etc.

Physical Exercise

Doing exercise is good for all. However, it is extra helpful for people with a high BMI.

Regular physical exercise will burn fat from your body. Therefore, there will be less levonorgestrel as its metabolites will have less fatty tissue to circulate and retain in your body. Additionally, your metabolic rate will increase, helping you get rid of Plan B soon.


Several supplements can help you eliminate Plan B from your system.

  • You can take Calcium-d-glucarate, a beta-glucuronidase inhibitor, helping in renal excretion.
  • Activated charcoal is another supplement that can use to quicken Plan B excretion.
  • You can also use Betaine supplements to increase amino acids in your system to modify your Ph-level. It will help acidify your urine.

Remember, before starting any supplements, always consult your physician first.

How Can You Know If Plan B Worked?

After taking Plan B, a common query is, did it work. And the next one is – “how long does plan b stay in your system.”

Plan B usually stays in your system for around 5 – 7 days. But, in this period, how to tell if it has worked.

Well, you can get the confirmation of the efficiency of Plan B only in one way. Wait for your next period. However, take a pregnancy test if your period is late for more than a week: you might be pregnant!

Now, it may raise a question, can you still get pregnant after taking Plan B?

Yes, you can get pregnant after taking the pill – they aren’t abortion pills. There is a chance that around 0.6 to 2.6% of women may still get pregnant after taking it. Moreover, if you have unprotected intercourse after taking the pill, it won’t work, and you must take it again.

But how do you know if Plan B worked before your period – is there a way? No, unless your next period starts, you can’t say anything for sure that the pill worked.

Will Plan B work after 6 days of unprotected sex? No, the synthetic progesterone hormone works better if taken sooner – within 3 days. Sperm can stay in your body for around 5 days. Now, if the eggs are already fertilized in between, after 6 days, pills can’t do anything.

Signs That Plan B Didn’t Work

No contraceptive is 100% effective. There is still a tiny chance that the pill may not work.

However, several signs can indicate the news that Plan B has failed to save your unprotected love. These signs may include-

  • Light-headedness or dizziness
  • Heavy, swollen, or tender breasts
  • Fatigue and sleepiness
  • Light pink or brownish vaginal spotting
  • Pain, discomfort, cramps, or backache
  • Diarrhea and vomiting
  • Sudden change in your food preference
  • Frequent urination
  • Smell sensitivity

Plan B Before, After, and During Ovulation

Timing is most crucial while dealing with unprotected sex with Plan B. Most importantly, ovulation. It’s the most paramount period to determine the success rate of Plan B.

Before Ovulation

Plan B works most efficiently if you take it before your ovulation starts. The reason is – Plan B usually prevents eggs from releasing from the ovary or implanting in the uterus.

So, taking the pill before ovulation increases the chances of preventing unwanted pregnancy.


During Ovulation

Plan B is less likely to be ineffective during ovulation. There’s a high chance that you might get pregnant.

Now, the pill usually delays your ovulation – prevents egg releasing and implanting. But you are ovulating means the eggs have already been released, fertilized, and implanted. And, you are pregnant.

After Ovulation

If you have already ovulated, Plan B may not prevent your pregnancy. You can opt for other contraceptives – implant, IUD, shot, vaginal ring, patch, etc.

Plan B Side Effects

Plan b contains more levonorgestrel than regular contraceptives. So, the increased synthetic hormone may cause several side effects, impacting your regular life.

7 Common Side Effects

These are the common side effects you may encounter after taking a pill.

  • Nausea, diarrhea, and vomiting
  • Bleeding between periods
  • Abdominal pain
  • Fatigue and dizziness
  • Headache
  • Breast tenderness
  • Irregular period

How Long Does Plan B Side Effects Last?

The severity and duration of Plan B side effects vary from woman to woman.


The most common effects are abdominal pain and irregular menstruation. Nausea, pelvic pain, or vomiting usually resolve after 2 or 3 days. In more severe cases, it can last about a week or more.

As for irregular menstruation, you will notice the symptoms not until your next period starts.


What are plan b symptoms 2 weeks later, you take them?

Usually, there’s a lower chance of plan B symptoms 2 weeks later. However, consult your doctor immediately if you feel excessive lower stomach pain even after 2 to 3 weeks of taking Plan B. However, it’s a rarity.

How long does plan b bloating last?

It usually goes away in 2 to 4 days. However, you may feel it in severe cases even after a week.

Take Away

Either you forget to wear a condom, or it breaks; unprotected intercourse always imposes the risk of pregnancy. However, emergency contraceptive Plan B One Step can help you prevent your pregnancy if you take action immediately.

But, how long does plan b stay in your system after taking it? The synthetic progesterone hormone usually takes 5-7 days to remove from your system. In the meantime, you may face some side effects, which usually resolve within days.

Remember, safe sex is the best sex.

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