Phytosterols (plant sterols and stanols)
Summary
Plant sterols and stanols block some cholesterol absorption in the gut. Across more than 120 trials, 0.6–3.3 g a day lowered LDL by about 6–12%, levelling off near 3 g (grade A). They also lower blood beta-carotene, and people with the rare inherited disorder sitosterolemia should avoid them.
Key facts
- About 6–12% at 0.6–3.3 g/day; little extra benefit above about 3 g/day (124 studies)[1]
- 0.34 mmol/L (8.8%) lower LDL at about 2.15 g/day (84 trials)[2]
- At least 1.3 g/day plant sterol esters or 3.4 g/day stanol esters, in two servings with meals[6]
- Beta-carotene about 16% lower at an average 2.5 g/day; vitamins A and D unchanged[3]
- A rare inherited disorder in which plant sterols build up to 30–100 times normal levels[5]
- 3 graded human outcomes on this page
- October 13, 2026
How it works
EstablishedPlant sterols and stanols resemble cholesterol and compete with it for absorption in the intestine, so less dietary and bile cholesterol is absorbed; the body partly compensates by making more. In a capsule trial, absorption efficiency fell about 20% and cholesterol synthesis rose about 20%, with a net fall in LDL.[4][3]
What the human research says
Human trials only, one row per outcome. The form column shows what each trial actually tested. Grades follow our evidence-grading policy.
At a glance: strongest evidence per outcome
| Outcome | Grade | Effect | Strongest evidence | Rows |
|---|---|---|---|---|
| Cholesterol | Grade A | Improved | Meta-analysis · n = 9,648 · 2014 | 2 rows |
| Nutrient absorption | Grade A | Worsened | Meta-analysis · n = 3,306 · 2017 | 1 row |
Every graded row
| Outcome | Effect | Grade | Best evidence | PMID |
|---|---|---|---|---|
| LDL cholesterol across dose ranges | Improved | Grade A | Meta-analysis · n = 9,648 · 2014 Adults in 124 randomized controlled studies (201 strata) Form: Plant sterols or plant stanols, mostly in foods · Dose: 0.6–3.3 g/day (average 2.1 g/day; range 0.2–9 g) · Duration: Varied by study (typically weeks) LDL fell gradually with dose, by an average of 6–12% at 0.6–3.3 g/day, levelling off at about 3 g/day; sterols and stanols behaved alike. | 24780090 (opens PubMed)Source [1] |
| Blood fat-soluble vitamins and carotenoids | Worsened | Grade A | Meta-analysis · n = 3,306 · 2017 Adults in 41 randomized trials Form: Plant sterols or stanols · Dose: Average 2.5 g/day · Duration: Varied by trial Beta-carotene fell 16% (10% after adjusting for lower cholesterol), alpha-carotene 14% and lycopene 12%. Vitamin A (retinol) and vitamin D did not change; tocopherol changes disappeared after cholesterol adjustment. | 27591863 (opens PubMed)Source [3] |
| LDL, plant sterol levels and cholesterol absorption | Improved | Grade D | Crossover RCT · n = 25 · 2012 Adults heterozygous for an ABCG8 sitosterolemia gene variant (10) and controls (15) Form: Plant sterol capsules · Dose: About 1.6 g/day with supper · Duration: 4 weeks per period LDL fell in both groups (heterozygotes 3.12 to 2.73 mmol/L), cholesterol absorption fell about 20%, and blood plant sterols rose, more so in heterozygotes. | 22378727 (opens PubMed)Source [4] |
Forms
| Form | Elemental % | Absorption (human data) | GI tolerance | Studied for |
|---|---|---|---|---|
| Sterol- or stanol-enriched foods (spreads, dressings, dairy) | Varies[6] | LDL lowering did not differ between fat-based and non-fat-based foods or dairy and non-dairy foods; solid foods worked slightly better than liquids above 2 g/day.[2] | Lower blood carotenoids at about 2.5 g/day.[3] | LDL cholesterol (most trials) |
| Plant sterol capsules or softgels | Varies[7][8] | About 1.6 g/day in capsules with supper lowered LDL and cholesterol absorption in a 4-week trial.[4] | Not reported as a problem in the 4-week capsule trial.[4] | LDL cholesterol |
| Plant sterols vs plant stanols | Varies[1] | Dose-response curves for LDL were similar for sterols and stanols.[1][2] | Carotenoid lowering was seen with both.[3] | LDL cholesterol |
Studied doses
Doses studied in human trials ranged from about 0.6 to 3.3 g a day of plant sterols or stanols, averaging 2.1–2.5 g a day; a few trials used up to 9 g a day.[1][2][3]
Interactions
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
Medicines that can lower levels
- Carotenoids (beta-carotene, alpha-carotene, lycopene)RCTBlood beta-carotene fell about 16%, alpha-carotene 14% and lycopene 12% at an average 2.5 g/day; retinol and vitamin D did not change.[3]
Who should be careful
- Sitosterolemia
- In this inherited disorder plant sterols accumulate in blood and tissues and can cause early atherosclerosis; supplements add to the sterol load.[5]
- Carriers of a sitosterolemia gene variant
- In carriers of an ABCG8 variant, blood plant sterols rose more than in controls on 1.6 g/day, although LDL fell normally.[4]
- Low carotenoid intake
- Sterols and stanols lowered blood beta-carotene and other carotenoids; vitamin A and D levels did not change.[3]
- Pregnancy and breastfeeding
- One label advises against use in pregnancy, when trying to conceive or breastfeeding; the trials cited did not study these groups.[7]
Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.
Sitosterolemia
How to read the label
- Per serving, not per capsuleOne label lists 500 mg of plant sterols per 1-capsule serving once daily; another lists 400 mg per softgel with two softgels a day (800 mg). Both are well below the roughly 2 g/day typical of the trials.[7][8][1][2]
- Esters vs free sterolsFDA health-claim amounts are written as sterol or stanol esters (1.3 g or 3.4 g a day), whereas trial doses are usually given as free sterols; compare like with like.[6][1]
- Split the doseFDA claim wording calls for two servings eaten at different times with food, and single daily intakes tended to work slightly less well in the 2009 meta-analysis.[6][2]
Cost per studied dose, without the sales pitch
Compare any product you already have by the amount it delivers, not by capsule count or front-of-pack weight.
Cost per studied dose
Enter the price, servings and the amount per serving from your label.
Frequently asked questions
How much do plant sterols lower LDL?
Meta-analyses of 84 and 124 trials found LDL about 6–12% lower at 0.6–3.3 g a day, with little extra effect beyond about 3 g.[1][2]
Do capsules work as well as fortified foods?
Most trials used foods, but a 4-week trial of about 1.6 g/day in capsules also lowered LDL. Food format made little difference in the 2009 meta-analysis.[4][2]
Do plant sterols affect vitamins?
They lowered blood beta-carotene by about 16% and some other carotenoids, but not vitamin A (retinol) or vitamin D.[3]
Who should not take plant sterols?
People with sitosterolemia, a rare inherited disorder in which plant sterols build up in the body and raise heart risk.[5]
What does the FDA allow labels to say?
Foods with enough sterol or stanol esters may carry a coronary heart disease risk claim; the daily levels are 1.3 g sterol esters or 3.4 g stanol esters in two servings with meals.[6]
Sources
- [1]LDL-cholesterol-lowering effect of plant sterols and stanols across different dose ranges: a meta-analysis of randomised controlled studies.. Br J Nutr, 2014. meta-analysis
- [2]Continuous dose-response relationship of the LDL-cholesterol-lowering effect of phytosterol intake.. J Nutr, 2009. meta-analysis
- [3]Plasma fat-soluble vitamin and carotenoid concentrations after plant sterol and plant stanol consumption: a meta-analysis of randomized controlled trials.. Eur J Nutr, 2017. meta-analysis
- [4]Serum lipids, plant sterols, and cholesterol kinetic responses to plant sterol supplementation in phytosterolemia heterozygotes and control individuals.. Am J Clin Nutr, 2012. crossover-RCT
- [5]Sitosterolemia. MedlinePlus Genetics, U.S. National Library of Medicine, 2016. fact-sheet
- [6]21 CFR 101.83: Health claims: plant sterol/stanol esters and risk of coronary heart disease (CHD). U.S. Food and Drug Administration (Electronic Code of Federal Regulations), 2026. guideline
- [7]Plant Sterols 500 mg (Bluebonnet), DSLD label 179280: 500 mg plant sterols (210 mg beta-sitosterol, 100 mg campesterol, 70 mg stigmasterol) per 1-capsule serving, once daily; contains soy. NIH Office of Dietary Supplements, Dietary Supplement Label Database, 2018. label
- [8]Maximum Strength Plant Sterols (Swanson), DSLD label 337814: 400 mg phytosterols per 1-softgel serving, two softgels daily (800 mg/day); contains soy. NIH Office of Dietary Supplements, Dietary Supplement Label Database, 2025. label
What changed
- Strict adversarial pass: PMIDs re-checked; Ras 2014 n estimated from the PMC full text and labelled as an estimate. Fixed a label comparison that mixed free sterols with FDA ester amounts. Sitosterolemia (MedlinePlus Genetics) and carotenoid lowering kept in safety; DSLD labels verified per serving.
- First draft rebuilt from scratch after the earlier draft files were lost. Every PMID checked against NCBI esummary and abstracts read for each row. FDA health-claim amounts read from 21 CFR 101.83 on eCFR; sitosterolemia from MedlinePlus Genetics. Label amounts re-read from the DSLD API as per-serving amounts: 500 mg per 1-capsule serving (label 179280) and 400 mg per softgel, 2 softgels a day (label 337814).