How long does MiraLAX stay in your system

Every part of the body is delicate and works to make your body healthy. How does it feels when bowel movements become less frequent and stools become difficult to pass, that’s constipation and miralax can help you empty your bowls frequently. However many people tend to ask , how long does miralax stay in your system after using it ? This article will explore everything about miralax and long it does it stays in your system.


What is MiraLAX?

MiraLAX is a brand-name, over-the-counter (OTC) medication. It’s classified as an osmotic laxative. MiraLAX is used to treat constipation. It’s typically used for short-term treatment, but in some cases, it’s used long-term to treat chronic (long-lasting) constipation. MiraLAX is also sometimes used for colonoscopy bowel preparation. For most people, taking MiraLAX will cause a bowel movement within one to three days of taking it. One study of its effectiveness focused on people who had fewer than two bowel movements per week. MiraLAX increased their number of bowel movements to 4.5 per week, compared to 2.7 per week in people taking a placebo.

How long does Miralax stay in your body system

Another study found that 52 percent of people with chronic constipation were successfully treated with MiraLAX.


Drug Facts

  • Generic Name: Polyethylene glycol 3350
  • Brand Name: Miralax, GaviLAX, GlycoLax
  • Drug Availability: Over the counter
  • Therapeutic Classification: Osmotic laxative
  • Available Generically: Yes
  • Controlled Substance: N/A
  • Administration Route: Oral
  • Active Ingredient: Polyethylene glycol 3350
  • Dosage Form: Powder for solution, packet

MiraLAX forms

MiraLAX only comes as a powder. You mix MiraLAX powder into four to eight ounces of water or another beverage and drink it as a liquid. MiraLAX itself doesn’t come in a liquid form. It also doesn’t come as a tablet or pill.

Miralax powder

Bottles of MiraLAX powder contain either 7 doses, 14 doses, 30 doses, or 45 doses. Also available are boxes containing single-serve packets of MiraLAX powder. The boxes contain 10 or 20 packets each.

Uses of MiraLAX

This medication is used to treat occasional constipation. It works by holding water in the stool to soften the stool and increases the number of bowel movements. It is known as an osmotic-type laxative.This medication is also available without a prescription. If you are taking this medication for self-treatment, it is important to read the manufacturer’s package instructions carefully so you know when to consult your doctor or pharmacist.


How to Take Miralax

To take Miralax, in the morning of your procedure, mix all 238 grams of MiraLAX powder with 64 ounces of clear liquid at room temperature until MiraLAX powder has dissolved. Take 1 cap (17 grams) of MiraLAX mixed with 8 oz of liquid for breakfast, lunch, and dinner.

Drink half of the Miralax mixture in the morning and the other half in the afternoon. After cleansing is complete, start taking a smaller dose of Miralax per day as directed by your doctor.

During the 3-day cleanse, your child will take Miralax in the amount shown in the weight chart above. DO NOT stop Miralax at this stage. The dose can be changed in small increments every 3 days. When preparing the colon, you can repeat the above dose every 10-15 minutes.


A bowel movement usually starts within 1 hour of the first dose, but it may take longer for some people. For most people, MiraLAX will cause a bowel movement within one to three days of ingestion. 

How long does miralax stay in your system

Research is lacking on the time it takes for MiraLax’s active ingredient to leave the body.

However, according to studies, peak levels of PEG-3350 in the bloodstream occurred two to four hours after taking a 17 g dose. MiraLax starts producing bowel movements within one to three days.


These studies confirmed that PEG-3350 is absorbed in a small quantity in the gastrointestinal (GI) tract, which includes the stomach and intestines and is rapidly excreted from the body via the feces.

A typical Miralax dose is eliminated 48 to 72 hours after consumption.

The effects of MiraLax only last for a day or so. It works as it travels through your digestive system. Its effects gradually decrease as it is passed out of your body with the stool.


How fast does Miralax work?

When used as directed for constipation, MiraLAX should produce a bowel movement in 1 to 3 days without harsh side effects. It does not typically cause a sudden feeling of urgency like some other laxatives.

Contact your doctor if you have used MiraLAX for 7 days and still have not had a bowel movement. Do not use MiraLAX for more than 7 days without your doctor’s approval.

MiraLAX side effects

MiraLAX can cause mild or serious side effects. The following list contains some of the key side effects that may occur while taking MiraLAX. This list does not include all possible side effects.


For more information on the possible side effects of MiraLAX, or tips on how to deal with a troubling side effect, talk with your doctor or pharmacist.

More common side effects

The more common side effects of MiraLAX include:

  • diarrhea or loose stools
  • gas (flatulence)
  • nausea
  • stomach pain
  • bloating

These side effects may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk to your doctor or pharmacist.

Serious side effects

Call your doctor right away if you have serious side effects. Call if your symptoms feel life-threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following:

  • Dehydration. Diarrhea caused by MiraLAX can cause fluid loss and dehydration. Seniors have a higher risk of diarrhea and dehydration. Symptoms of dehydration include: thirst, fatigue, dizziness, confusion, dry mouth, irritability, no tears when crying (in children), no wet diapers for several hours (in children)
  • Allergic reactions. Although not common, some people can have an allergic reaction to MiraLAX. In rare cases, allergic reactions can be severe and include anaphylaxis. Symptoms of allergic reaction can include: rash, itchy skin, runny nose, trouble breathing, swollen lips, tongue, or throat.

Alternatives to MiraLAX

MiraLAX is an osmotic laxative used to treat constipation. There are other osmotic laxatives, and other types of laxatives, that can also be used to treat constipation. Examples of these laxatives include:

  • Osmotic laxatives. These products work by drawing water into the colon (large intestine), which softens the stool and can cause the colon to contract. These effects help to produce a bowel movement. Examples of osmotic laxatives include:
    • lactulose (Enulose, Kristalose)
    • magnesium citrate
    • magnesium hydroxide (Milk of Magnesia)
  • Bulk-forming laxatives. These products work like osmotic laxatives, drawing water into the colon to make the stool softer. But in addition to that, they contain fiber to bulk up the stool, which naturally stimulates movement of the colon to pass the stool. Examples of bulk-forming laxatives include:
    • calcium polycarbophil (FiberCon, Fiber-Lax)
    • wheat dextrin (Benefiber)
    • methylcellulose (Citrucel)
    • psyllium (Konsyl, Metamucil, others)
  • Stool softeners. These products work by drawing water into the stool itself to make it softer and easier to pass. They don’t stimulate a bowel movement, as many laxatives do. Examples of stool softeners include:
    • docusate (Colace, Kao-Tin, Surfak, others)
  • Stimulant laxatives. These products work by irritating the intestines and causing them to contract. They also work by increasing water in the intestines. Both of these actions help cause a bowel movement. Examples of stimulant laxatives include:
    • bisacodyl (Dulcolax, others)
    • senna (Ex-Lax, Senokot, others)

What Are Reasons I Shouldn’t Take Miralax?

Do not take Miralax if you are allergic to any of its ingredients or have a known or suspected bowel obstruction. It should also not be used in people with kidney disease unless approved by their healthcare provider or FDA

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