Does Metamucil Lower Cholesterol?

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What is Metamucil?

Metamucil is a natural fiber supplement whose main ingredient is psyllium husk.

Psyllium husk, also known as ispaghula, is a soluble fiber extracted from the outer coating (husk) of the seed of the plant Plantago. 

When you consume soluble fiber, such as psyllium husk, it absorbs water in your intestine, causing it to swell and form a highly viscous gel matrix. The high water-holding ability and the gel remaining intact throughout the entire gastrointestinal tract provide the health benefits of psyllium husk, particularly in lowering cholesterol. (1,¹ 2)²

Psyllium husk is one of the most common supplemental fibers due to its effective and safe cholesterol-lowering properties.

Metamucil is commercialized in several forms, such as powders, capsules, biscuits, and gummies. All of which contain psyllium husk. Each product supplies a different fiber content and is designed for diverse health and fiber goals.

In addition to lowering cholesterol, Metamucil is thought to help maintain blood sugar levels, support appetite control (help you feel fuller for longer), treat constipation and diarrhea, and support digestive health.

Metamucil and its effect on cholesterol

Metamucil may help to reduce total cholesterol and LDL cholesterol – also known as “bad” cholesterol – due to its active ingredient, psyllium husk.

So how exactly does Metamucil lower cholesterol?

The established mechanism for psyllium husk in Metamucil to lower cholesterol is directly related to bile acids.

The process tends to occur as follows: (1,³ 2)⁴

  • As psyllium enters and moves along your small intestine, it absorbs liquid, which forms a highly viscous gel – perfect for trapping bile acids.

  • Once the “sticky” gel reaches the end of your small intestine, where the active reuptake of bile acids occurs, the gel matrix traps and eliminates bile acids via stools.

  • This reduces bile acid content in the body, causing liver cells to compensate by using LDL cholesterol from the blood to synthesize more bile acids, maintaining sufficient bile for digestion.

  • The clearance of LDL cholesterol from the blood effectively lowers LDL cholesterol and total cholesterol without affecting HDL cholesterol levels – the “good” cholesterol.

Does Metamucil lower cholesterol in other ways?

Yes, there are two other proposed ways that Metamucil may lower cholesterol:

  1. When you consume Metamucil, it may slow the absorption of glucose and other nutrients in the small intestine, which helps to maintain your sugar levels and reduce glucose peaks. Low blood glucose levels decrease cholesterol synthesis.⁵

  2. An increase in the viscosity of intestinal contents is thought to be essential in stimulating the growth of “good” bacteria in your gut, which may reduce blood cholesterol concentrations. (2)⁶

Other health benefits of Metamucil

Metamucil gives your body adequate time to absorb nutrients from food and allows the delivery of nutrients into the last part of your small intestine, where nutrients are not normally present or absorbed.

The cholesterol-lowering benefit of psyllium in Metamucil may also work as an additive to the effects of statin drugs, with an LDL-cholesterol lowering effect equivalent to doubling the statin dose. This could be particularly important for patients who cannot tolerate higher doses of a statin drug.

The pros and cons of taking Metamucil


  • Natural product

  • Minimal side effects

  • Taking Metamucil is convenient. It can be taken almost anywhere, at any time.

  • It comes in a variety of forms and flavors to suit different preferences.

  • Detailed instructions on how and when to consume the product

  • You will know exactly how much soluble fiber you are consuming, so it may be a great way to help you meet your recommended daily fiber intake.

  • Guidelines on how much water you need to consume with each product, which is useful in avoiding dehydration

  • Relatively inexpensive


  • Possible unpleasant side effects such as bloating, discomfort, and abdominal cramps

  • Though fiber supplements do provide plenty of health benefits, they lack the vitamins, minerals, and other healthy substances that fiber-rich foods could provide. Therefore, it’s encouraged to obtain fiber from fiber-rich dietary sources initially and to use supplements only when needed.

  • Some Metamucil products contain sugar, sweeteners, sodium, gelling agents, and phenylalanine. Thus, it may interfere with certain diets and health goals.

  • Ensure you are taking the powders in drink form, as the powder could swell in your throat and cause choking.

  • If you currently take medications, it could interfere with their absorption, so it is recommended you take your medications two hours before or after taking Metamucil.

How to use Metamucil

Metamucil must be taken with an adequate intake of fluids — at least eight ounces of water or other liquid per serving (water is recommended). You should also drink plenty of fluids throughout the day to avoid discomfort and dehydration.

Metamucil should be introduced slowly and gradually to decrease side effects, starting with a single dose for the first week, then increasing by one dose each subsequent week until the therapeutic goal is achieved.

If you have constipation, treating it before taking any Metamucil products is recommended.

Metamucil is available in a variety of forms, including:

  • Powders

  • Capsules

  • Gummies

  • Fiber thins

The following instructions are according to Metamucil’s website:


It is recommended to take one rounded teaspoon (for Metamucil Sugar-Free and Premium Blend Powders) or tablespoon (for Metamucil with Real Sugar powders), or one packet (for Metamucil on-the-go! powders) up to three times per day to achieve its cholesterol-lowering effects. Each serving will provide around 2.4g of soluble fiber. 

Preparation instructions:

  1. Add one heaped teaspoon or tablespoon or one packet to a glass

  2. Mix with at least 8oz. of cool liquid, ideally water

  3. Drink promptly


It is recommended to take five capsules, up to four times per day (20 capsules per day), to achieve its cholesterol-lowering effects. Each serving will provide around 1.8g of soluble fiber. 

Usage instructions:

Swallow one capsule at a time in an upright position. Ensure you have at least 8oz of water with each full serving (five capsules or your individual full serving), not with each capsule. 

Gummies and fiber thins

These are great sources of fiber that can help to achieve your daily fiber goals. However, Metamucil’s gummies and fiber thins are not recommended for lowering cholesterol. 

Before taking Metamucil, or any fiber supplement, it is essential to understand the purpose of the supplement and your treatment or health goals. This will help you to understand what dose and product are adequate for you. You can seek professional advice from your doctor if you are unsure, as they will be able to provide safe and appropriate advice.

Metamucil side effects and precautions

Metamucil is generally well tolerated by most people. However, you may experience some discomfort and side effects. 

Common side effects include:

  • Bloating

  • Flatulence

  • Indigestion

  • Nausea

  • Stomach pain

  • Heartburn

  • Diarrhea

  • Constipation

Side effects may occur as your body adjusts to an increased soluble fiber intake. However, if the side effects continue for an extended period or become severe, it is recommended to discontinue the use of Metamucil and seek professional health advice from your doctor. 

Although Metamucil is considered safe for most individuals, it is advised not to take Metamucilif you have the following:

  • Allergy to psyllium

  • Constipation and/or fecal impaction

  • You are dehydrated

  • Rectal bleeding or anal fissures

  • Severe stomach pain, nausea, and/or vomiting

  • Trouble swallowing

  • Upper respiratory tract infections

  • Recently undergone gastric band surgery

Other precautions with taking Metamucil to consider:

Metamucil may reduce the absorption of vitamins, minerals, proteins, and energy, but this is unlikely in healthy individuals who consume Metamucil in amounts within the recommended ranges.

Psyllium may decrease blood pressure accentually. If you have symptoms of low blood pressure, discontinue use and seek medical advice.

Talk to your doctor

Before taking any fiber supplement, including Metamucil, it is important to talk to your doctor first.

They will discuss potential risks and side effects and whether a fiber supplement is appropriate for you. They will consider your health, lifestyle, other medications you are taking, and family health history, among other individual factors.

This will help your doctor find the best cholesterol-lowering treatments for you, whether that be taking fiber supplements or not. 

The lowdown

Metamucil may be an effective tool to reduce your LDL-cholesterol and total cholesterol, protecting you against heart disease. It is a safe, natural, and convenient strategy while providing several other health benefits. 

However, as there are some potential side effects and precautions when taking Metamucil or any other soluble fiber supplements, it is relevant to discuss these aspects with your doctor to ensure Metamucil is appropriate for you.

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