Miralax vs. Colace for Constipation: 5 Key Differences to Consider

You stroll into your local pharmacy, determined to find a solution for your constipation. Upon arrival, you find yourself faced with a myriad of products advertising relief. You’ve heard about two options — Miralax (polyethylene glycol 3350) and Colace (docusate) — that seem to be popular choices. But which one is better suited for your needs?

The short answer: It depends. Miralax and Colace work differently for constipation. And there may be certain situations where one is recommended over the other, or you may be advised to take both. Below, we break down five key differences between Miralax and Colace that should help in choosing what’s right for you.

1. Miralax and Colace work differently to relieve constipation

Miralax is an osmotic laxative. It works by drawing water into the intestines, which softens the stool and increases pressure in the colon. This can help make your stool easier to pass.

Colace is an emollient laxative, but you may be more familiar with the term “stool softener.” It works by causing water and fat to move into the stool. This can result in softer stools to prevent or lessen straining from constipation. However, some evidence suggests that it doesn’t work any better than placebo (a pill without medication).

Since Miralax and Colace work differently to treat constipation, they’re sometimes recommended together. But in general, it’s usually best to start with one laxative and add others if needed, unless directed otherwise.

2. Miralax is available as an oral powder, while Colace comes in a capsule

Miralax is available as a tasteless, odorless powder. It’s mixed with 4 oz to 8 oz of liquid, such as water or juice, before drinking. You can purchase Miralax in a multi-dose bottle or single-dose powder packet. If you’re traveling, the powder packets can be a convenient option.

Colace is available as oral capsules. You can find it in two different doses: 100 mg (regular dose) and 50 mg (low dose). The 50 mg capsules, marketed as Colace Clear, do not contain artificial dyes, unlike the 100 mg capsules.

If you have difficulty taking pills, Colace may not be the best option. However, there are other OTC docusate products that come in liquid form, if preferred.

Good to know: For convenience, the Colace line of products offers a combination pill called Colace 2-in-1. It contains docusate with sennosides — a stimulant laxative. Stimulant laxatives tend to work faster than Miralax or Colace (docusate) on their own. They also stimulate intestinal muscles to move stool along for a bowel movement.

3. Miralax is a better option than Colace for constipation from medications

There are many medications that can cause constipation. Certain pain medications, blood pressure pills, and iron supplements are common culprits. In this case, Miralax will likely work better than Colace to get things moving again. However, your healthcare provider or pharmacist may suggest taking Miralax and Colace together.

It’s important to keep in mind that laxatives may not address the underlying cause of constipation, as is the case with constipation from opioid medications. And your constipation will usually continue as long as you’re taking the medication. If OTC options aren’t doing the trick, your healthcare provider may tweak your regimen or add a prescription constipation treatment.

Keep in mind: If you’re dealing with constipation from medications, lifestyle changes might help. Adding fiber to your diet, drinking more water, and getting regular exercise are a few recommended adjustments.

4. Miralax is a first-choice laxative during pregnancy, but Colace is also considered safe

If you’re experiencing constipation during pregnancy, you may be searching for treatments that are considered safe. When it comes to laxatives, experts consider polyethylene glycol solution (Miralax) as a first-choice option.

After you drink Miralax, most of it stays in your gastrointestinal (GI) tract as it moves through your body. Because it’s not absorbed very well, there’s a lower exposure risk for a fetus. Colace is also considered safe during pregnancy. But it may not work as well as other options.

5. There are certain situations where Colace may be recommended

As mentioned above, stool softeners like Colace can help lessen straining that comes along with constipation. This can be useful for health conditions where straining during bowel movements can be problematic, such as with hemorrhoids, heart conditions, or after surgery.

If you’re treating hemorrhoid symptoms, Colace is one option you can try at home, since straining can cause or worsen hemorrhoids. Increasing your fiber and water intake is also important. And OTC steroid creams can help with symptoms such as swelling and itching.

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Written by:

Alyssa Billingsley, PharmD

Alyssa Billingsley, PharmD, is the director of pharmacy content for GoodRx. She has over a decade of experience as a pharmacist and has worked in clinical, academic, and administrative roles.

Reviewed by:

Austin Ulrich, PharmD, BCACP

Austin Ulrich, PharmD, BCACP, is a board-certified ambulatory care clinical pharmacist. In his early career, he provided direct patient care in a variety of settings, including hospital and community pharmacies, and in a primary care clinic as a clinical pharmacist.

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