Beta-sitosterol
OTHER NAME(S): β-sitosterol, beta-sitosterol
Overview
Beta-sitosterol is a plant sterol, which is a substance that is naturally found in many plant-based foods. Although it is commonly used to improve prostate health, its benefits for this use are not well defined. Common side effects include loose stools and diarrhea. Before taking beta-sitosterol, make sure to tell your health care provider about any health conditions you have or medicines you are taking. Beta-sitosterol is also one of many ingredients in plant sterol products, which are used for other purposes.
Uses
What is beta-sitosterol used for?
Beta-sitosterol is commonly used to improve prostate health, but its benefits are not well defined.
Note: The FDA has not reviewed beta-sitosterol for safety and effectiveness. Learn more about dietary supplements here.
How does beta-sitosterol work (mechanism of action)?
Beta-sitosterol is a type of substance known as a plant sterol (phytosterol). It is naturally found in plant-based foods, such as vegetable oils, nuts, breads, and cereals. Beta-sitosterol is also an ingredient in plant sterol products, which contain many different plant sterols and are often used for lowering cholesterol levels. See Plant Sterols for more information on how these substances may lower cholesterol.
The most popular use of beta-sitosterol supplements is for improving prostate health, especially for an enlarged prostate (benign prostatic hyperplasia, or BPH). When the prostate is enlarged, it can become hard to fully empty your bladder and may increase how often you need to pee. But most research shows that beta-sitosterol does not help reduce the size of the prostate or help with any symptoms of BPH. This may be due to the fact that your body does not absorb much beta-sitosterol from foods or dietary supplements. Most beta-sitosterol stays in your gut and is passed into your stool (poop).
How should I store beta-sitosterol?
You should store beta-sitosterol according to the product label. Most dietary supplements should be kept in a cool, dry location that is out of the reach of children and pets and not in direct sunlight.
Side Effects
What are the most common side effects of beta-sitosterol?
The most common side effects of beta-sitosterol are loose stools and diarrhea. These side effects may vary depending on the dose you are taking or the specific product you are using. Tell your health care provider if you have any of these side effects that bother you.
There may be other side effects of beta-sitosterol that are not listed here. Contact your health care provider if you think you are having a side effect of a supplement. In the U.S., you can report side effects to the FDA at www.safetyreporting.hhs.gov or by calling 888-SAFEFOOD (888-723-3366). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.
What are the serious side effects of beta-sitosterol?
While less common, the most serious side effects of beta-sitosterol are described below, along with what to do if they happen.
Severe Allergic Reactions.Beta-sitosterol may cause allergic reactions, which can be serious. Stop taking beta-sitosterol and get help right away if you have any of the following symptoms of a serious allergic reaction.
- Breathing problems or wheezing
- Racing heart
- Fever or general ill feeling
- Swollen lymph nodes
- Swelling of the face, lips, mouth, tongue, or throat
- Trouble swallowing or throat tightness
- Itching or skin rash
- Bumps on the skin called hives that can be red, pink, white, or brown depending on your skin tone
- Nausea or vomiting
- Dizziness, feeling lightheaded, or fainting
- Stomach cramps
- Joint pain
Precautions
Who should not use beta-sitosterol?
Allergies to Ingredients. People who are allergic to any of the following should not take beta-sitosterol.
- Beta-sitosterol
- Any of the ingredients in the specific product
Your pharmacist can tell you all of the ingredients in the specific beta-sitosterol products they stock.
Low-Sterol Diet. If your health care provider has told you to follow a diet low in plant sterols, you should not take beta-sitosterol supplements. For example, if you have a rare condition called sitosterolemia (phytosterolemia), you should avoid beta-sitosterol supplements.
What should I know about beta-sitosterol before using it?
Beta-sitosterol is a dietary supplement. It cannot be marketed to treat or cure a disease.
Read and follow the directions on the specific product you are taking, or take it as recommended by your health care provider.
Keep beta-sitosterol out of the reach of children.
If you have symptoms of an enlarged prostate, such as having a hard time peeing, a weak stream, or dribbling when you pee, call your health care provider. Beta-sitosterol may not be the right option for treating prostate problems or other urinary problems.
The FDA has not tested beta-sitosterol products to confirm that they contain the ingredients stated on their labels. Some dietary supplements have been tested by third-party organizations to confirm that they contain the ingredients listed on their labels and do not contain any harmful chemicals. Learn more about how to choose a safe dietary supplement product here.
What should I tell my health care provider before using beta-sitosterol?
Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if beta-sitosterol is right for you.
In particular, make sure that you discuss any of the following.
Soy Allergy.Some beta-sitosterol supplements are made from soy. If you are allergic to soy, you may also have an allergy to products made from soy. But you may be able to take beta-sitosterol that is made from other sources. Read the label carefully, and talk to your health care provider before taking beta-sitosterol products made from soy.
Pregnancy. It is not known if or how beta-sitosterol could affect pregnancy or harm a fetus. Tell your health care provider if you are pregnant or plan to become pregnant.
Breastfeeding. It is not known if beta-sitosterol passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed.
Interactions
Does beta-sitosterol interact with foods or drinks?
There are no known interactions between beta-sitosterol and foods or drinks.
It is unknown if drinking alcohol will affect beta-sitosterol.
Does beta-sitosterol interact with medicines (drug interactions)?
There are no known interactions between beta-sitosterol and medicines. Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.
The interactions between beta-sitosterol and medicines are not fully understood. As with most dietary supplements, the research on drug interactions with beta-sitosterol is incomplete. Always check with your health care provider before taking beta-sitosterol with any medicines.
Dosing
What should I do if I accidentally use too much beta-sitosterol?
If you or someone else has used too much beta-sitosterol, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.
Read the product label closely, and speak with a health care provider about how to take beta-sitosterol safely. Do not take double or extra doses, even if you miss a dose.
References
- American Journal of Clinical and Experimental Urology: “The use of beta-sitosterol for the treatment of prostate cancer and benign prostatic hyperplasia.”
- EFSA Journal: “Scientific Opinion on the substantiation of health claims related to plant sterols and plant stanols and maintenance of normal blood cholesterol concentrations and maintenance of normal prostate size and normal urination pursuant to Article 13(1) of Regulation (EC) No 1924/2006.”
- National Cancer Institute: “Prostate Cancer, Nutrition, and Dietary Supplements (PDQ)–Health Professional Version,” “beta-sitosterol.”
- StatPearls [Internet]: “Sitosterolemia (Phytosterolemia).”