Compare Metamucil vs. Miralax

Head-to-head comparisons of medication uses, side effects, ratings, and more.

Metamucil
(Psyllium)

Miralax
(Polyethylene Glycol)

Helps get things moving. The natural psyllium fiber in Metamucil (Psyllium) does more than relieve constipation. It lowers cholesterol, keeps blood sugar levels healthy, and makes you feel less hungry between meals.Helps get things moving. Miralax (Polyethylene Glycol) provides effective relief of constipation without "cramping" your style.
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Reviews & ratings
Button Group. All currently active
Button Group. All currently active
5.164079822616408Metamucil
Reviews for Metamucil (Psyllium)
71%
of people say Metamucil (Psyllium) is worth it
45%
say it works well
10%
say it's a big hassle
Reviews for Miralax (Polyethylene Glycol)
74%
+3% vs. Metamucil (Psyllium)
54%
+9% vs. Metamucil (Psyllium)
10%
Same vs. Metamucil (Psyllium)
Side effects
MetamucilMiralax

We haven’t found good data for Metamucil side effects.

FDA side effect reports for Metamucil »

The Miralax FDA package insert doesn’t have numbers about how common side effects are.

More about Miralax side effects »
How it works
MetamucilMiralax
Metamucil (Psyllium) is a fiber-based laxative. It adds bulk and moisture to your intestine, which softens stool and makes it easier to pass.Miralax (Polyethylene Glycol) is an osmotic laxative. It uses osmosis to keep more water in your intestine, which softens your stool and makes it easier to pass.
Type of medication
MetamucilMiralax
Laxative
Bulk-producing
Over-the-counter
Laxative
Osmotic
Over-the-counter
Available as
MetamucilMiralax
  • Liquid
  • Liquid
Used for (click to learn more)
MetamucilMiralax
Risk factors for serious side effects
MetamucilMiralax
  • Age 60 or older
  • Malignancy
  • Other condition that causes blockage or narrowing of bowel
  • Taking medications that cause constipation
  • Sensitivity to psyllium
Detailed Metamucil (Psyllium) risks & warnings »
  • Taking with medications that cause electrolyte imbalance
  • Age 60 or older
  • Women of childbearing age
  • Age 60 or older
  • Malignancy
  • Other condition that causes blockage or narrowing of bowel
  • Taking medications that cause constipation
Detailed Miralax (Polyethylene Glycol) risks & warnings »
Pregnancy category
MetamucilMiralax
NFDA pregnancy category (Unknown)

The FDA hasn’t classified this medicine’s effects on unborn babies. Talk with your doctor about this medicine if you’re pregnant or planning on it.

See the FDA package insert
CFDA pregnancy category (Weigh risks vs. benefits)

Research studies with animals found harmful effects on unborn babies. It hasn’t been properly studied in humans. The benefits might outweigh the risks even if you’re pregnant. Talk with your doctor.

See the FDA package insert
Alcohol
No specific alcohol-related info.No specific alcohol-related info.
Food
  • It has multiple health benefits, good to control your hunger between meals, improves your blood sugar and lowers cholesterol levels.
  • Talk to you doctor about eating certain foods and getting more exercise to help prevent your constipation.
  • Talk to you doctor about eating certain foods and getting more exercise to help prevent your constipation.
Kidneys and liver
No specific kidneys and liver-related info.
  • Ask your doctor before you take Miralax if you have nausea or vomiting, irritable bowel syndrome (IBS), kidney disease, or sudden changes in your stool for more than 2 weeks.
Sex
No specific sex-related info.No specific sex-related info.
Sleep
No specific sleep-related info.No specific sleep-related info.
Weight
No specific weight-related info.No specific weight-related info.
Upsides and benefits
MetamucilMiralax
  • Psyllium is the most recommended brand of natural fiber laxative
  • Some people feel that taking Psyllium is a hassle, but most think it's worth it.
  • It has multiple health benefits, good to control your hunger between meals, improves your blood sugar and lowers cholesterol levels.
  • Studies show it works better than a stool softener for constipation.
  • Miralax is the most recommended laxative by pharmacists and doctors.
  • Most people felt it was worth the hassle.
  • It's gluten and sugar free.
  • It causes little to no cramping, bloating, gas, or feelings like you "have to go right now" compared to some other medicines to treat constipation.
  • Works differently than other over-the-counter laxatives so it's a great alternative if other medicines haven't worked.
Downsides and risks
MetamucilMiralax
  • You may have to take Psyllium daily for 1-3 days to see full effects.
  • If you don't take it with enough liquid, it could swell, block your throat and cause choking.
  • Not the best choice for people who have swallowing problems or aren't able to drink lots of liquids.
  • Psyllium contains psyllium. Don't take if you have an allergy to psyllium from breathing it in or swallowing it.
  • Can cause gas and mild belly cramps.
  • You have to dissolve Miralax in a beverage and drink it versus taking a pill.
  • It's not for children 16 years or younger.
  • Miralax doesn't work overnight. It can take up to 2-4 days to have a bowel movement.
  • It's not recommended that you take it for more than a week, so it you haven't had any success, you'll need to call your doctor for other laxative options.
Tips from our pharmacists for people taking the medication
MetamucilMiralax
  • Psyllium works in about 12-72 hours for constipation.
  • It's important to take each dose with at least 8 ounces (a full glass) of water or other liquid (not hot liquids).
  • Mix powder well and drink right away up to 3 times a day (build up to this slowly), but not for more than one week.
  • Don't take Psyllium within 2 hours before or after taking other medicines. It may interact and affect how they work.
  • If you take Psyllium then have chest pain, vomiting, trouble breathing or swallowing, get medical help immediately.
  • Ask your doctor before taking Psyllium if you have stomach pain, nausea, vomiting or had sudden changes in your stool for more than 2 weeks.
  • Ask your doctor about giving Psyllium to anyone younger than 12 years.
  • Stop taking Psyllium and call your doctor if you have pain, swelling or bulging in your belly, rectal bleeding or have not had a bowel movement after taking.
  • Talk to you doctor about eating certain foods and getting more exercise to help prevent your constipation.
  • Dissolve Miralax powder in 4 to 8 ounces of water, juice or other drink (cold or hot) once a day.
  • Works in about 1 to 3 days. Don't use for more than 1 week.
  • Miralax is available in four different size dose bottles. It also come in pre-measured single-dose packets to make dosing easier or if you travel.
  • Ask your doctor about giving it to anyone younger than 17 years.
  • Doesn't cause as much bloating, cramping or feelings like you "have to go right now" as other medicines to treat constipation.
  • Ask your doctor before you take Miralax if you have nausea or vomiting, irritable bowel syndrome (IBS), kidney disease, or sudden changes in your stool for more than 2 weeks.
  • Stop using Miralax and call your doctor if you have pain, cramping, swelling or bulging in your belly, diarrhea, rectal bleeding or find you need to use for more than 1 week.
  • Talk to you doctor about eating certain foods and getting more exercise to help prevent your constipation.
Learn more
More about MetamucilSide effectsReviews & ratingsAlternativesFDA package insert
More about MiralaxSide effectsReviews & ratingsAlternativesFDA package insert