What Is Beta-Sitosterol?

Plant-based compound may reduce your risk of heart disease

Beta-Sitosterol capsules, tablets, avocado, almonds, and pistachio nuts

Verywell / Anastasia Tretiak

Beta-sitosterol is one of several plant-based substances known as phytosterols. It is similar in chemical structure to the cholesterol your body makes.

Naturally found in plants, beta-sitosterol can be consumed through food sources such as vegetable oils, nuts, seeds, and legumes. It is also available in supplement form, as well as a lipid emulsion.

Beta-sitosterol is sometimes used to reduce high cholesterol. It has also been studied for a host of other health conditions. This article will review its potential uses, side effects, dosage, and more.

Dietary supplements are not regulated in the United States, meaning the Food and Drug Administration (FDA) does not approve them for safety and effectiveness before products are marketed. When possible, choose a supplement that has been tested by a trusted third party, such as USP, ConsumerLabs, or NSF. However, even if supplements are third-party tested, that doesn’t mean that they are necessarily safe for all or effective in general. It is important to talk to your healthcare provider about any supplements you plan to take and to check in about any potential interactions with other supplements or medications.

Supplement Facts

●     Active Ingredient(s): Beta-sitosterol

●     Alternate Name(s): SIT, B-sitosterol, Sitosterol

●     Legal Status: Legal to sell over-the-counter (OTC)

●     Suggested Dose: There is no universal dose for beta-sitosterol.

●     Safety Considerations: Beta-sitosterol is generally recognized as safe. The most common side effects involve gastrointestinal upset.

Uses of Beta-Sitosterol

Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian, pharmacist, or doctor. No supplement is intended to treat, cure, or prevent diseases.

Research has shown that phytosterols, including beta-sitosterol, can play a role in helping certain medical conditions.

However, many studies on beta-sitosterol have been animal studies. And although we can often learn from animal studies, we cannot definitively say that the results in animals will be the same in humans.

Despite this, there is some interesting research involving beta-sitosterol and various health concerns that we will look at next.

High Cholesterol

A review from 2016 looked at numerous studies on beta-sitosterol and its potential role in reducing cholesterol. Researchers found that beta-sitosterol can reduce the amount of LDL "bad" cholesterol absorbed by your body. Because beta-sitosterol and cholesterol have similar structures, your body will choose to absorb beta-sitosterol and excrete cholesterol instead.

The beta-sitosterol eaten from plants competes with cholesterol for absorption in your intestines. Over time, this can reduce the risk of atherosclerosis or hyperlipidemia, conditions that can lead to heart disease. In short, phytosterols like beta-sitosterol are thought to reduce your risk of heart disease.

To see the LDL cholesterol-lowering effects, consuming 2 grams (g) of beta-sitosterol and other phytosterols per day is recommended.

The Food and Drug Administration (FDA) has approved the claim that phytosterols (including beta-sitosterol) in the diet can reduce your risk of heart disease. However, anything less than 1.3 grams per day of phytosterols does not lower your heart disease risk.

Benign Prostatic Hyperplasia

Beta-sitosterol may aid in the treatment of an enlarged prostate. This condition is also known as benign prostatic hyperplasia (BPH) and can block the flow of urine.

Though research is dated, beta-sitosterol has been linked to improved symptoms in males (sex assigned at birth) with BPH. A systemic review of studies totaling 519 males with BPH found that beta-sitosterol improved urinary symptoms. It's not known exactly how beta-sitosterol improves BPH, but it is thought that it works by reducing inflammation in the prostate.

A new study or review on this subject is needed to provide an update on the use of beta-sitosterol for BPH.

Beta-sitosterol cannot directly treat BPH on its own. Traditional drugs used for this condition can help treat decreased or hesitant urinary flow.

Cancer

Advocates of beta-sitosterol claim that it may have anti-cancer properties. However, most of the evidence supporting these claims is based on test tube studies (also called in vitro), which we can learn from but not use as strong evidence.

A trial from 2010 that used both in vitro and in vivo models found that beta-sitosterol made from tropical milkweed (Asclepias curassavica) slowed the growth of human colon cancer cells. The in vivo models of the study included male rats.

Similarly, a 2003 study found that beta-sitosterol induced apoptosis, or cell death, in breast cancer cells. Apoptosis is key to stopping the spread of cancer cells. But, again, this research was done in a test tube rather than on humans.

None of this should suggest that beta-sitosterol can directly impact cancer cells. You should always follow the treatment plan prescribed by your healthcare provider for any medical condition.

Diabetes

Although human trials are lacking, there is evidence from animal studies that beta-sitosterol could have an effect on diabetes.

In one study on rats, beta-sitosterol was found to provide both antioxidant and antidiabetic effects. The results showed that beta-sitosterol reduced blood sugar levels in the rats, possibly due to increased insulin response.

In another study, rats with diabetes taking 20 milligrams/kilograms of beta-sitosterol per day had normalized blood sugar and insulin levels at the end of 30 days of taking the supplement.

Human trials on the effects of beta-sitosterol on diabetes are certainly needed. Because we mostly have evidence from animal trials, we cannot yet say for sure that beta-sitosterol will improve outcomes for people with diabetes.

Other Potential Uses

Beta-sitosterol has also been studied in the following conditions:

What Are the Side Effects of Beta-Sitosterol?

Beta-sitosterol and other phytosterols are generally considered safe. But, as with any supplement or medication, side effects are possible. These side effects may be common or severe.

Common Side Effects

The most common side effects associated with taking beta-sitosterol are gastrointestinal.

Common side effects of beta-sitosterol include:

Severe Side Effects

Little to no severe side effects have been found in studies on beta-sitosterol and other phytosterols. When side effects do occur, they tend to be one of the common side effects just discussed.

People with a rare genetic condition called sitosterolemia may be more likely to experience severe side effects. People with sitosterolemia are unable to properly absorb and excrete beta-sitosterol. This leads to a buildup of beta-sitosterol, which can cause serious side effects like atherosclerosis and other health issues.

To avoid common or severe side effects, talk to your healthcare provider before taking beta-sitosterol supplements.

Beta-sitosterol tablets

Verywell / Anastasia Tretiak

Precautions

Due to the lack of safety research, children and people who are pregnant or lactating should avoid using beta-sitosterol. While no research has shown that beta-sitosterol is dangerous for these populations, there is not enough research to know if it is safe.

As previously discussed, beta-sitosterol should not be used by people with sitosterolemia, a rare genetic disorder affecting the body's ability to use and get rid of beta-sitosterol properly. If a person with sitosterolemia takes beta-sitosterol supplements, narrowing of the arteries could occur. This could eventually result in blocked blood flow, increasing the risk of a heart attack or stroke.

Taking more beta-sitosterol than is recommended on the label or by a healthcare provider could result in side effects. Getting advice and guidance from a knowledgeable provider before starting any new supplement is always best.

Dosage: How Much Beta-Sitosterol Should I Take?

Always speak with a healthcare provider before taking a supplement to ensure that the supplement and dosage are appropriate for your individual needs.

There are no universal guidelines for how to use beta-sitosterol supplements, including dosage.

A dose of 2 grams per day of beta-sitosterol has been found to be beneficial in lowering LDL cholesterol. Other research has suggested that taking up to 3.4 grams of beta-sitosterol per day can help lower high cholesterol, but taking more than 3.4 grams a day would provide no further benefits.

For benign prostatic hyperplasia, a dose of 60 milligrams two times per day has been suggested.

Talk with a healthcare provider to find the right beta-sitosterol dosage for you,

What Happens If I Take Too Much Beta-Sitosterol?

Beta-sitosterol is not thought to be toxic. An overdose is also not likely with this supplement.

There is no upper limit (UL) in place for beta-sitosterol. An upper limit is a maximum quantity or dose that if exceeded may cause adverse effects.

Since side effects are possible when taking beta-sitosterol, it's best to remain within the recommended dose provided by your healthcare provider or as listed on the supplement's label. Side effects are more likely to happen if you take more than needed.

The most likely side effects you may experience if you take too much beta-sitosterol are:

Interactions

Many supplements interact with other medications or nutrients. It's important to tell your healthcare provider about all the medications you're taking before starting a new supplement.

Beta-sitosterol may interact with:

  • Statins
  • Zetia (ezetimibe)
  • Carotenoids, a type of antioxidant found in plant foods that are orange, red, and yellow

Statins

Beta-sitosterol may interact with statins, a medication used to lower LDL cholesterol and reduce the risk of a heart attack or stroke. Statins may increase the absorption of beta-sitosterol.

Ezetimibe

Ezetimibe, another drug, may also interact with beta-sitosterol. Ezetimibe, also known as Zetia, also lowers LDL cholesterol and may block the absorption of beta-sitosterol in the body.

Carotenoids

A 2017 meta-analysis of randomized controlled trials found that phytosterols can interact with carotenoids. The analysis concluded that phytosterols reduced carotenoids in the blood. However, it's important to point out that this study did not differentiate the type of phytosterols used, so we do not know if beta-sitosterol was included in the review.

It is essential to carefully read the ingredient list and nutrition facts label when choosing any supplement to know which ingredients and how much of each ingredient is included. Before starting beta-sitosterol, please review the supplement label with your healthcare provider to discuss potential interactions with foods, other supplements, and medications.

How to Store Beta-Sitosterol

Beta-sitosterol supplements are stable at room temperature. They can degrade quickly if exposed to excessive heat or sunlight. Always store your supplements in their original light-sensitive container, ideally in a cool, dry place in your home.

Avoid allowing the supplements to become wet or overly hot or cold. Beta-sitosterol supplements do not need to be refrigerated.

You should only use beta-sitosterol supplements until the point of expiration. Discard the supplements as indicated by the expiration date on the label.

Similar Supplements

Some other supplements on the market may be similar to beta-sitosterol. It is usually not necessary or recommended to take two supplements for the same health condition. Talk with your healthcare provider about which supplement would be best for you and your health.

Supplements that may be similar and used for the same health conditions as beta-sitosterol include:

  • Pygeum: An herb that may be used to treat benign prostatic hyperplasia (BPH), pygeum has been used as an adjunct therapy for men with BPH and has been shown to improve symptoms and urine flow.
  • Niacin: One of the B-vitamins, Niacin supplements have been used to treat high cholesterol. Niacin is thought to work by raising your HDL "good" cholesterol and lowering your LDL "bad" cholesterol.
  • Alpha-lipoic Acid: This supplement has also been studied in type 2 diabetes. It has been found to increase insulin sensitivity and increase glucose uptake by cells, which results in lower blood sugar levels.
  • Resveratrol: A polyphenol and antioxidant, resveratrol is said to contain anti-inflammatory effects. It may help reduce low-grade inflammation.
  • Biotin: A deficiency in biotin, one of the B-vitamins your body needs, can result in hair loss. Using biotin supplements may help with hair loss.

Frequently Asked Questions

  • Are beta-sitosterol supplements safe for benign prostatic hyperplasia?

    Beta-sitosterol supplements appear to be safe for most men who take them for BPH. For some people, though, beta-sitosterol may cause an upset stomach or other gastrointestinal side effects.

    If you experience side effects from taking beta-sitosterol for BPH, check with your healthcare provider to be sure that your symptoms are not related to a different condition that needs other treatment.

  • Is beta-sitosterol a blood thinner?

    For heart health, beta-sitosterol works by lowering the amount of LDL "bad" cholesterol in your blood because it is thought to block cholesterol absorption. Research has not shown that beta-sitosterol also acts as a blood thinner.

    Researchers are looking to see if beta-sitosterol may have other benefits for heart health, including preventing blood clots, but the research is not there yet.

  • Do I need to take a beta-sisoterol supplement?

    It is always best to get the nutrients you need from food first. However, sometimes it can be difficult for some people to get a variety of nutritious foods into their diet, and supplements can be the answer.

    Also, if beta-sitosterol supplements have been recommended to you by a healthcare provider due to a health condition then a supplement may be warranted.

Sources of Beta-Sitosterol & What to Look For

Beta-sitosterol and other phytosterols are widely available in food. Because of this, it is easy for most people to get plenty of beta-sitosterol through their diet.

A food-first approach to all nutrients is best, including beta-sitosterol. However, a beta-sitosterol supplement may sometimes be needed, like when a healthcare provider recommends it.

Food Sources of Beta-Sitosterol

Beta-sitosterol is found in plant-based foods. A wide variety of foods contain beta-sitosterol, including nuts, oils, wheat, and beans.

Good food sources of beta-sitosterol include, but are not limited to:

There are many ways to fit these and other beta-sitosterol-containing foods into our diet. While nuts make great snacks, beans and lentils can be a great side dish at dinnertime. And cooking with vegetable oil is thought to be heart-healthy.

Beta-Sitosterol Supplements

You can find beta-sitosterol supplements in capsule, tablet, or soft gel form. Some versions of the supplement are vegan or gluten-free.

There may be other ingredients present in beta-sitosterol supplements, like fish oil, magnesium, or soy. Be sure to check the ingredients label on the bottle before purchasing a beta-sitosterol supplement to check for any ingredients you are allergic to.

Dietary supplements are largely unregulated in the United States. As a result, the contents and/or concentration of active ingredients may differ from one brand to the next.

To better ensure safety and quality, opt for supplement brands that have been tested and certified by an independent certifying body like the U.S. Pharmacopeia (USP), ConsumerLab, or NSF International.

Summary

Beta-sitosterol is a phytosterol that is found in plants. Because it is similar in structure to cholesterol, beta-sitosterol is sometimes used to reduce cholesterol levels. It has also been studied for its role in improving symptoms of benign prostatic hyperplasia. Although beta-sitosterol is available in supplement form, there are many ways you can get it through diet.

Side effects of beta-sitosterol are typically not severe and may only occur if you take more than is recommended. Therefore, beta-sitosterol is recognized as a generally safe supplement.

Always speak with a healthcare provider before starting a new supplement, and be sure to share any health conditions you may have or medications you are taking.

Originally written by
Cathy Wong
Cathy Wong

Cathy Wong is a nutritionist and wellness expert. Her work is regularly featured in media such as First For Women, Woman's World, and Natural Health.

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