Miralax vs Benefiber: Choosing the Best Fiber Supplement for Your Need

Miralax vs Benefiber

When it comes to maintaining digestive health and regularity, fiber supplements can play a crucial role in your daily diet. Two popular choices on the market — Miralax and Benefiber — are for those who seek to increase their fiber intake.

Although both help manage bowel movements, they differ significantly in composition, mechanism of action, and usage recommendations.

In our comparison, we’ll look at how Miralax, a laxative, and Benefiber, a fiber supplement, help with different digestive issues. We’ll check what’s in them, any side effects, and when to use each to help you choose what’s best for your health.

Miralax is a laxative that helps with constipation by making stool softer and increasing bowel movements. It’s used for short-term constipation relief.

Benefiber, in contrast, has wheat dextrin, a natural fiber that supports digestion and regularity. Unlike Miralax, Benefiber is a daily fiber supplement, not a laxative. It moves through the digestive system without breaking down, adding bulk to stool.

Although both are fiber supplements, they act differently. Let’s dive into their ingredients to understand how Miralax and Benefiber work.

What is Miralax?

Miralax is generically known as polyethylene glycol 3350, is an osmotic laxative. This is often recommended by healthcare professionals for the treatment of occasional constipation.

Unlike stimulant laxatives, Miralax works by holding water in the stool to soften it and making it easier to pass without causing a sudden urgency.

This process usually takes one to three days to be effective. The active ingredient, polyethylene glycol, is not absorbed into the body and therefore is considered safe for over-the-counter use when taken as directed. It is important to note that Miralax is meant for short-term use and not as a long-term solution to digestive health.

Ingredients of Miralax

The main ingredient in Miralax is polyethylene glycol 3350 (PEG 3350). It’s a synthetic compound that works as an osmotic agent. It has the unique property of being able to retain water, which in turn softens stool and enhances bowel movements.

PEG 3350 doesn’t get broken down or taken in by the body, so it’s a safe choice for dealing with constipation. It’s safe for adults and kids over six for occasional use, but make sure to follow the package directions or those from a healthcare provider.

Miralax uses and benefits

Here are the key benefits of using Miralax:

  • Mainly used to relieve occasional bouts of constipation, Miralax can help restore regular bowel movements.
  • It is often regarded as a gentle option, as it does not cause harsh urgency or cramping commonly associated with stimulant laxatives.
  • Polyethylene glycol 3350, the active component of Miralax, does not absorb into the bloodstream which makes it safe for most people when used as directed.
  • Miralax powder can be mixed with any hot or cold beverage, which makes it easy to ingest.
  • It is available over-the-counter and does not require a prescription, which makes it easily accessible.
  • Approved for children with a doctor’s recommendation, giving an option for pediatric patients suffering from constipation.

Miralax side effects

While Miralax is generally safe when used as directed, some users may experience side effects. These include:

  • Bloating
  • Gas
  • Cramps
  • Nausea
  • Increased thirst
  • Diarrhea
  • Dizziness

If you experience any of these side effects, it is essential to stop using Miralax and consult your healthcare provider.

What is Benefiber?

Benefiber is a natural fiber supplement made from wheat dextrin. It dissolves in water, adds bulk to your diet, and helps keep your bowels healthy and regular. It also supports the growth of good gut bacteria for a balanced gut flora.

Since Benefiber is gluten-free, it can be utilized by those with gluten intolerance or celiac disease. It is tasteless, non-thickening, and can be easily incorporated into your diet without affecting the flavor or consistency of your food and beverages.

Benefiber has a bit of wheat in it, but the makers say it’s gluten-free since it has very little gluten (less than 20 ppm). Still, they warn that if you have trouble with gluten or have celiac disease, it’s best not to use Benefiber unless a healthcare pro says it’s okay.

Ingredients of Benefiber

The primary ingredient, wheat dextrin, is a natural kind of fiber from wheat starch. It melts in liquids, doesn’t make things thick, and tastes like nothing. This type of fiber soaks up water in your gut, making a gel that helps you feel full and pushes waste through your tummy.

Benefiber Uses and Benefits

Here are several benefits and uses of Benefiber:

  • Benefiber as a daily supplement can assist in reaching the recommended daily fiber intake, particularly for those struggling with dietary fiber.
  • Benefiber is safe for individuals with gluten issues as it is gluten-free and meets FDA regulations for gluten-free products.
  • The main ingredient in Benefiber, wheat dextrin, promotes good digestive health by fostering the growth of beneficial gut bacteria.
  • Benefiber, a non-thickening powder, can be easily added to beverages and soft foods without changing their texture or taste.
  • Regular use of Benefiber can help ease occasional constipation by aiding food movement in the digestive system.
  • By enhancing a fiber-rich diet, Benefiber can aid in weight management and stabilizing blood sugar levels.

Benefiber Side Effects

Benefiber is usually fine, but if you’re new to high-fiber foods, you might have some minor side effects while your body gets used to it.

  • Bloating
  • Gas
  • Temporary changes in bowel habits
  • Abdominal discomfort

It is key to drink plenty of water when you increase your fiber intake and to increase fiber slowly to minimize potential side effects.

Miralax vs Benefiber: Dosages and Directions

Miralax vs Benefiber dosages

Both Miralax and Benefiber are designed to be taken orally but differ in their dosages and directions due to their varying mechanisms of action:

Miralax Dosage and Directions

  • Adults and children 17 years of age and older: The typical dose is 17 grams (about 1 heaping tablespoon) of powder per day. It should be mixed into 4–8 ounces of a beverage (like water, coffee, tea, or juice) and taken once a day.
  • Usage: Use no more than 7 days unless directed by a doctor. According to the FDA, it is advised to measure the dose using the cap provided with the product, which contains a line to indicate the correct level of powder.
  • Adjustments: The dose might change depending on how you respond and how you feel, but a healthcare provider should help with any changes.

Benefiber Dosage and Directions

  • Adults: Add 2 teaspoons of Benefiber powder to 4–8 ounces of a beverage or soft food (hot or cold), stirring until dissolved, up to 3 times daily.
  • Children 6–12 years of age: Take 1 teaspoon 3 times daily.
  • Children under 6 years: Consult a doctor before use.
  • Usage: Start with a smaller amount and gradually increase to the desired daily amount to minimize potential digestive discomfort. The maximum adult dose is 5 tablespoons per day.
  • Hydration: Adequate water intake is essential when taking fiber supplements to ensure proper function and reduce chances for side effects.

When you choose between them, think about what your body needs, what you like, and advice from doctors. Some people like how polyethylene glycol works quickly to help with short-term issues. Others prefer a slower approach with Benefiber, a fiber supplement that helps with digestion.

Miralax vs Benefiber: The Differences

While Miralax and Benefiber both help keep your bowels regular, they do it in different ways. Miralax adds water to your colon, while Benefiber gives your gut the fiber it needs to keep a healthy balance of gut bacteria.

Mechanism of Action:

  • Miralax: Increases bowel movement frequency by drawing water into the colon, softening stool for easier passage.
  • Benefiber: Promotes regularity by supporting the growth of healthy intestinal bacteria.


  • Miralax: Contains polyethylene glycol with low systemic toxicity potential.
  • Benefiber: Includes wheat dextrin, a natural water-soluble fiber extracted from wheat starch.


  • Miralax: Typically consumed orally, mixed into a liquid.
  • Benefiber: Non-thickening and tasteless, easily concealed in everyday foods and beverages.

Miralax vs Benefiber: The Similarities

Despite their various distinctions, Miralax and Benefiber share a common goal of supporting gastrointestinal health. They are both over-the-counter remedies that aim to improve regular bowel movements and relieve occasional constipation.

  • Over-the-counter Availability: No prescription is required for either Miralax or Benefiber, making them easy to purchase and use.
  • Digestive Health Support: Both products work to maintain digestive regularity, and when used as directed, they can alleviate the discomfort of constipation and associated symptoms.

Miralax vs Benefiber: Which is best for you?

Deciding between Miralax and Benefiber depends on your specific needs and preferences. If you’re looking for quick relief from constipation, Miralax’s osmotic effect may be the better choice.

On the other hand, if you’re focusing on long-term digestive maintenance with minimal taste or texture disruption to your daily routine, Benefiber could be the optimal solution for you.

Consider the following aspects when making your decision:

  • Immediate Relief vs Long-term Maintenance: Are you looking for immediate relief from constipation, or are you focused on long-term digestive health and regularity?
  • Taste and Texture: How do you like to consume your supplements? Miralax needs to be mixed with liquid, while Benefiber can be easily added to food or drink without affecting taste or texture.
  • Prefer Natural Ingredients? If you prefer natural products, Benefiber’s all-natural composition might be more appealing to you.

Precautions for Miralax and Benefiber

Both Miralax and Benefiber are considered safe for most users when taken as directed but there are important precautions to be aware of.

It is always recommended to consult with your doctor first before starting any new supplement, especially if you have underlying health conditions or are taking other medications.

Precautions for Miralax:

  • Consultation: If you have kidney disease or are on a sodium-restricted diet, consult your doctor before use, as Miralax contains sodium.
  • Allergies: Be aware of any potential allergies to polyethylene glycol.
  • Pregnancy and Breastfeeding: Talk to your provider if you are pregnant or breastfeeding to understand the safety of Miralax during these times.

Precautions for Benefiber:

  • Gluten Sensitivity: Benefiber contains wheat dextrin. While it is considered gluten-free by the FDA (containing less than 20 ppm of gluten), those with celiac disease or severe gluten intolerance should consult a doctor before use.
  • Allergies and Sensitivities: If you have allergies to wheat or other ingredients in Benefiber, avoid using this product.
  • Gastrointestinal Issues: If you experience any persistent gastrointestinal discomfort or changes in bowel habits that last more than 7 days, see a healthcare professional.

Drug Interactions:

Be careful of potential interactions with other medications. Fiber products, like Benefiber, may affect how your body absorbs medications. Miralax usually has fewer interactions, but you should still check with a healthcare provider.


Both Miralax and Benefiber carry warnings to discontinue use and consult a doctor if you experience rectal bleeding or fail to have a bowel movement after use, as these could be signs of a more serious condition.


In conclusion, while Miralax and Benefiber serve similar functions in promoting digestive health, they offer distinct benefits and mechanisms suitable for different preferences and needs. Miralax is a good choice for those who seek immediate relief from constipation, while Benefiber caters to those who prioritize long-term digestive maintenance with a natural fiber supplement.

It’s essential to evaluate personal health objectives, and dietary preferences, and consult with a provider before integrating either option into your regimen, ensuring safety and compatibility with your overall health plan.


Is Miralax considered a fiber supplement?

No, Miralax is not considered a fiber supplement. It is classified as an osmotic laxative, which works by drawing water into the colon. It softens stools and enhances bowel movements. Unlike fiber supplements that increase the bulk of stool by adding fiber to the diet, Miralax operates by a different mechanism to relieve constipation.

Can I take both Miralax and Benefiber together?

Yes, it is possible to take both Miralax and Benefiber together as they work differently in the body and do not share any known adverse interactions. However, it’s important to start with small doses to see how your body reacts and to consult with a healthcare provider to ensure that this combination is appropriate for your individual health needs.

Do I need a prescription for Miralax or Benefiber?

No, both Miralax and Benefiber are available over the counter, meaning you do not need a prescription to purchase them.

Can I use Miralax or Benefiber to help with weight loss?

Miralax and Benefiber are designed to improve digestive health rather than for weight loss, but some people use fiber supplements like Benefiber as part of their weight management plan due to fiber’s ability to promote feelings of fullness. However, Miralax does not contribute to weight loss as it works by drawing water into the colon to increase stool movement rather than affecting appetite or digestion.

Are there any special considerations for using Miralax or Benefiber with other medications or health conditions?

Yes, there are specific considerations when using these with other medications. Due to their fiber content, products like Benefiber may change the absorption of some medications, so it is advisable to take other medications either 1 hour before or 2 hours after taking fiber supplements. For Miralax, while it usually has fewer interactions with medications, it’s important for people with kidney disease or on certain medications to consult their healthcare provider due to its sodium content and the way it works in the body.




The information provided in this article is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Don’t ignore professional medical advice or put off seeking it just because of something you read here. Although we aim to offer precise and current information, we do not guarantee its completeness, accuracy, reliability, suitability, or availability for any purpose. Using the information in this document is at your own risk. We are not responsible for any losses or damages caused by our content.

Sharing is Caring

Leave a Comment

Related Articles