Beta-sitosterol is a natural waxy compound found in many plants. It is a phytosterol, which is a type of plant steroid with a chemical structure similar to that of cholesterol.
Beta-sitosterol is purported to benefit BPH (benign prostatic hyperplasia), high serum cholesterol, inflammation and weak immune system function.
Researchers have been studying this widely-distributed plant steroid for decades now, but more research is still needed to determine precisely how it works, and what benefits it offers in terms of human health. [1][2]
This article will review what beta sitosterol is, the pharmacological effects it has demonstrated in research, how it might benefit health, its safety, recommended dosages, and possible side effects and interactions.



- Supports healthy cholesterol levels
- Promotes cardiovascular health
- Helps maintain prostate health
What is Beta-Sitosterol?
Beta-sitosterol is a compound called a phytosterol that is molecularly similar to cholesterol.
It has been studied extensively in clinical research for male prostate health, along with saw palmetto extract.
Phytosterols are the major lipids that occur in higher plants. They cannot be synthesized inside the human body, and must be gained from foods, or supplements.
Phytosterols are very common in the human diet, with the most widely consumed being campesterol, sitosterol and stigmasterol.
According to Fortitech, “These plant fats have chemical structures that are nearly identical to the animal fat known as cholesterol, with the only difference being an additional alkyl (ethyl) group at the C-24 position on the side chain of the sterols.”. [3]
Sitosterol and sitosterolin are often referred to interchangeably. However, technically, sitosterolin is a glycoside of sitosterol.
Memidex states that a glycoside is a compound where a small, non-carbohydrate organic molecule is bound to sugar.
Numerous plants store chemicals in inactive glycosides. Glycosides also play many important roles in the health and maintenance of living organisms. [4]
Sitosterolin generally occurs in the same plants as sitosterol, although in much smaller amounts. [3] Both Sitosterols and sitosterolin are known to induce biological effects even in very small amounts. [3]
Plant Sterol History
Plant sterols were first described in terms of their chemistry in 1922. In the 1950’s researchers began to report that sterols could slow down the absorption of cholesterol from dietary sources inside the intestines. [3]
In the 1980s, statin drugs were developed and mass prescribed for treating various conditions involving lipid (fat) imbalance in the blood.
By helping to lower LDL (low density lipoprotein)-C (cholesterol), these drugs are said to help lower the risks for heart disease and stroke. [3]
The prevalence of statin drug prescriptions effectively tampered the research interests into plant sterols. However, statin drugs are now associated with various serious side effects.
Because of this, many people are looking into natural treatments for high cholesterol. This has renewed interest in beta-sitosterol, and other plant sterol compounds, which exhibit cholesterol-lowering properties in people with elevated levels. [3]
Why use a Beta-Sitosterol Supplement?
The Natural Medicines Comprehensive Database (NMCD) states that people use oral beta-sitosterol supplements today for: [2]
- Hypercholesterolemia (elevated serum cholesterol);
- ITP (idiopathic thrombocytopenia purpura);
- BPH (benign prostatic hyperplasia);
- Preventing immune suppression;
- Systemic lupus erythematosus;
- Enhancing sexual activity;
- RA (rheumatoid arthritis);
- Preventing colon cancer;
- Coronary heart disease;
Oral beta-sitosterol supplements are also used for prostatitis, gallstones, inflammation, HIV/AIDS and tuberculosis. They are also used for colds and flus, migraine headache, allergies, psoriasis, fatigue, cervical cancer and menopause.
This supplement has also been used to improve urinary function in men, especially when urination becomes slow or painful due to an enlarged prostate gland.
Beta-sitosterol is included in some topical formulations and used for treating burns and other wounds. [2]
Plant sterols are also added to foods. Some brands of margarines that contain beta-sitosterol are marketed for purposes of lowering serum cholesterol, and improving cardiovascular health in general. [5]
NMCD states that most people get between 175-200 milligrams (mg) of beta-sitosterol each day from the foods and beverages they consume. However, only about 5% of that gets absorbed into the bloodstream. [2]
Note that most of the uses for beta-sitosterol have not been substantiated in clinical trials. More research is needed to reliably determine efficacy for this supplement in any health condition.
Some of the ways that beta-sitosterol seems to work in specific health conditions will be reviewed below.
Lipid-lowering effects:
Plants sterols like beta-sitosterol, campesterol and stigmasterol are added to foods like margarine, beef and others. This is done because lipids (fats) are needed to make them more soluble. That is why margarine products often contain plant sterols: they make good carrier vehicles. [2]
Because such a small amount of oral beta-sitosterol gets absorbed from dietary supplement, this supplement does not cause atherosclerotic adverse effects, like cholesterol and triglycerides in many animal foods do. [2]
Some ground beef contains soybean phytosterols that are composed of 48% beta sitosterol, 26% campesterol and 21% stigmasterol. [2]
The human liver produces all the cholesterol needed in most healthy people; about 1 gram daily. Because of this, the extra cholesterol contained in foods can accumulate in the circulatory system and cause atherosclerotic plaques to develop.
These plaques are a major cause of clogged arteries (atherosclerosis), CAD (coronary artery disease), stroke and cardiovascular disease in general.
Beta sitosterol competes with and slows down the absorption of cholesterol in the intestines. NMCD states that it reduces the amount of cholesterol that gets absorbed by roughly 50%. [2]
Beta sitosterol capsule supplements may not distribute well inside the gut, which in turn reduces their capacity to slow down cholesterol absorption. Natural plant sources of beta-sitosterol, or other supplement types may work better. [2]
Beta-Sitosterol for Prostate Health:
Some animal research has suggested that beta sitosterol is beneficial for treating symptoms associated with BPH (benign prostatic hyperplasia); the medical term for a swollen or inflamed prostate gland. [2]
Beta sitosterol might help to improve BPH symptoms in a way similar to a prescription drug called Proscar (finasteride). [2]
According to RXList, “PROSCAR (finasteride), a synthetic 4-azasteroid compound, is a specific inhibitor of steroid Type II 5?-reductase, an intracellular enzyme that converts the androgen testosterone into 5?- dihydrotestosterone (DHT).”. [6]
Although Proscar seems to be more effective at treating BPH symptoms, beta-sitosterol works without causing side effects in most otherwise-healthy men.
In comparison, some of the side effects associated with Proscar include: “impotence, loss of interest in sex, trouble having an orgasm, abnormal ejaculation, swelling in hands or feet, swelling or tenderness in breasts, dizziness, weakness, feeling faint, headache, runny nose, skin rash, increased hair growth and/or decreased amount of semen released during sex.” [6]
NMCD reports that some laboratory research suggests that beta sitosterol may induce antiproliferative effects on cancerous prostate cells; meaning it might stop them rapidly replicating and progressing. This might be due to inhibition of certain growth factors. [2]
In animal studies, beta sitosterol has demonstrated prostate-shrinking effects, but this has not been duplicated in human trials. [2]
The FDA has not approved the use of Beta sitosterol as a drug for the treatment of BPH. However, it is a component of several prostate medications sold in Europe.
European doctors have prescribed this herbal extract to treat benign prostate enlargement and related symptoms affecting the lower urinary tract.
BPH:
In 2 separate double-blind, clinical trials, men who took beta sitosterol experienced significant improvements in BPH symptoms. In one trial, the benefits observed after 6 months of daily supplementation were still evident at an 18-month follow-up. [4]
Prostate.net asserts that “Patients looking for a natural approach to prostatitis and urinary health may turn to beta-sitosterol instead, because Beta-sitosterol works in a similar way to the drugs without causing undesirable sexual side effects.” [7]
Other herbs often recommended for BPH include saw palmetto, stinging nettle, and pumpkin seed. [8]
If you have BPH and think that beta sitosterol might make be a safe alternative to prescription drugs, then ask your doctor if it is right for you. Keep taking any medications you currently take in the meantime.
Hormonal effects:
By inhibiting the activity of 5-alpha reductase, beta sitosterol might slow down the conversion of testosterone into DHT (dihydrotestosterone). [2]
Research suggests that androgenic alopecia (hair loss) is caused by increased sensitivity to DHT. Hair follicles that are especially sensitive to DHT may develop dysfunction; decreasing the length of the growth phase, and their size.
By decreasing testosterone-to-DHT conversion, beta sitosterol may help to prevent or reverse hair loss due to hormonal imbalance. [2]
Further, beta sitosterol reduces cholesterol bioavailability when consumed at the same time from food sources, which may also decrease synthesis of both testosterone and DHT. [2]
Immune System Effects:
Some in-vitro studies suggest that beta sitosterol might stimulate immune system activity. Both beta sitosterol and its glycoside, beta sitosterolin appear to strengthen proliferative responses of immune system T cells. [2]
In one study, beta sitosterol seemed to improve inflammation, and mild immune suppression, seen in marathon runners after an event. [2]
Anticancer Effects:
Some early in-vitro evidence suggests that beta sitosterol might slow down human colon cancer cell growth. Although specific mechanisms are currently unclear, researchers think they involve inflammatory mediators, caspases and membrane signaling. [2]
Fortitech states, “Sterols and sterolins are absorbed from the intestinal tract along with other fats. Although these compounds are poorly absorbed, they exert their biological effects at extremely low concentrations, so limited absorption does not appear to be a problem.” [3]
Beta Sitosterol Health Benefits
NMCD reports that beta sitosterol is Likely Effective for BPH (benign prostatic hyperplasia) and hypercholesterolemia (high serum cholesterol). [2]
NMCD rates beta sitosterol Possibly Effective for familial cholesterolemia, Possibly Ineffective for tuberculosis, and Likely Ineffective for gallbladder disease. [2]
NMCD states there is insufficient reliable evidence to rate beta sitosterol in androgenic alopecia, RA (rheumatoid arthritis) and burns. [2]
All uses for beta sitosterol require more research to reliably determine any efficacies.
Beta-Sitosterol for Diabetes:
Some animal studies suggest that plant sterols and sterolins might help to reduce risk factors for diabetes and help to manage long-term symptoms of diabetes. [4]
In hyperglycemic (high blood glucose) and normal blood glucose rats, sterol and sterolin compounds both reduced fasting blood glucose levels, and increased fasting insulin levels. This seems to be due to stimulation of beta cells inside the pancreas that produce insulin. [4]
According to Dr. Michael Lam, beta sitosterol helps to normalize blood sugar levels in patients with type 2 diabetes. He says this occurs due to stimulating insulin secretion, and by inhibiting a liver enzyme called glucose-6-phosphatase. [8]
Dr. Lam states, “In the liver, the enzyme glucose-6-phosphatase is the primary pathway for conversion of dietary carbohydrates to blood sugar. Glucose-6-phosphatase dephosphorylates glucose-6-phosphate to yield free D-glucose. Free D-glucose passes into the blood, thus elevating blood sugar levels.” [8]
However, the apparent antidiabetic effects have not been proven by large-scale, reliable clinical research. More research is needed to know if and how this dietary supplement can benefit diabetes.
If you have diabetes and are considering a beta sitosterol supplement, then you should seek professional medical advice before starting to take one.
Beta-Sitosterol for Lowering Cholesterol:
A number of studies have reported that beta sitosterol slows down cholesterol absorption from the gastrointestinal tract.
According to NMCD, “Taking beta-sitosterol orally significantly reduces total and low-density lipoprotein (LDL) cholesterol levels, but has little or no effect on high-density lipoprotein (HDL) cholesterol levels.”. [2]
Although beta sitosterol has been studied for more than three decades regarding its lipid-lowering effects, NMCD reports that more research is needed to be sure of how it works, and if it is safe for long-term use.
You should discuss using beta sitosterol for lowering serum cholesterol levels with your doctor before beginning to take a supplement.
Additional Purported Health Benefits:
Dr. Lam states that beta sitosterol dietary supplements can also help to: [8]
- Reduce redness and swelling (inflammation);
- Enhance uterine tone;
- Heal peptic ulcers;
- Alleviate cramps;
He states that beta sitosterol also has antifungal, antibacterial and antiviral properties that might help to prevent and/or improve a number of infectious health conditions.
You should discuss any intended use for a beta sitosterol supplement with a doctor who understands your health history before beginning to use a supplement. Be sure to talk about any prescription drugs, illicit drugs and/or herbal supplements you may use.
Beta Sitosterol Deficiency
Sterols and sterolins are not considered to be essential nutrients for humans. Therefore there are no known deficiency symptoms to note.
However, it is generally believed that people who do not consume enough plant foods develop more health problems than those who do. [2]
Beta Sitosterol Food Sources
Sterols and sterolins occur naturally in numerous plants. Harvesting, processing and cooking can significantly reduce the nutritional content of plants, so choosing those that have been minimally processed or altered is best. [7]
Dr. Michael Lam states that beta sitosterol is found in nearly all plants, at least in small amounts. He says some of the best sources are wheat germ, soybeans, rice bran and corn oil. [8]
For optimal health and minimal toxins, always choose certified organic, non-GMO and contaminant-free foods and beverages.
Beta Sitosterol Supplements
NMCD reports that there are 391 different supplement products that claim to contain beta sitosterol. Tablets, powders and capsules are available. [2]
As with the foods you choose, look for beta sitosterol supplements that have been certified free of contaminants like pesticides, and that have not been genetically modified.
Take time to select dietary supplements from trustworthy manufacturers, and store your supplements in cool, dark locations.
Beta Sitosterol Dosage
There are no typical doses for natural plant compoundss like beta sitosterol. However, there are some dosages reported from research studies. Some of these include: [7, 8]
- 300 mg up to 5 grams daily for reducing serum cholesterol levels;
- 160 mg twice daily for prostatitis;
- 60-135 mg/day for prostatitis;
Dr. Lan states that most American diets lack sufficient intake of beta sitosterol. He says the average American gets only 200-300 mg/day, which is not adequate. [8]
Eating more wheat germ, soybeans, rice bran and corn oil can help to naturally raise your level of this plant nutrient. For many, supplementation is a more reliable way to increase intake.
Prostate.net states, “When purchasing beta-sitosterol, you want to make sure the supplement label clearly states the amount of beta-sitosterol in the product. If beta-sitosterol is just one of several plant sterols in the supplement, the beta-sitosterol should make up at least half of the total amount of sterols in the product.”. [7]
Beta Sitosterol Side Effects
Michigan Medical states that men taking beta sitosterol for BPH experience few adverse effects. Some men report stomach upset and indigestion.
If you are male and are have trouble urinating, then you should see your doctor to rule out any serious possible causes – like prostate cancer for instance. Most diseases are more easily treatable when diagnosed as early as possible.
Although food products with plant sterols added, like margarine, may have some positive effects for balancing blood lipids like cholesterol, the effects of long-term consumption of these products has not been established.
Likewise, the long-term safety of beta sitosterol supplementation is not understood.
Do not use beta sitosterol, or any other natural medicine, to prevent or treat any serious health condition without first discussing it with your doctor.
Beta Sitosterol Interactions
NMCD reports that beta sitosterol supplements might cause interactions with certain diseases, drugs and supplements. Seek medical advice and use caution if taking beta sitosterol along with any of the following:
Drugs used to treat sitosterolemia; a rare disease marked by improper lipid storage in the body. Some drugs that are used for this condition include ezetimibe (Zetia), pravastatin (Pravachol) and other HMG-CoA reductase inhibitors (“statins”); including atorvastatin (Lipitor), cerivastatin (Baycol), fluvastatin (Lescol), and lovastatin (Mevacor).
Beta sitosterol may alter blood levels of alpha-carotene, beta-carotene, and vitamin E (alpha tocopherol).
Beta sitosterol is not known to cause false readings in any laboratory tests.
Discontinue using beta sitosterol and other dietary supplements at least 2 weeks before surgeries.
- Michigan Medicine, Beta-Sitosterol Plant Extract, Accessed June 19, 2017
- Natural Medicines Comprehensive Database, Beta-Sitosterol Monograph, Accessed June 19, 2017
- Sterols (Sitosterol) and Sterolins (Sitosterolin), Accessed June 19, 2017
- Memidex, Glycoside, Accessed June 19, 2017
- Beta Sitosterol, Accessed June 19, 2017
- RXList, PROSCAR, Accessed June 19, 2017
- Does Using Beta-sitosterol for Prostatitis Treatment Work? October 14, 2016, Accessed June 19, 2017
- Michael Lam, MD, MPH, Beta-Sitosterol, Accessed June 19, 2017
Article last updated on: July 19th, 2018 by Nootriment