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Limited evidenceLongevity & antioxidants

Vitamin E

Vitamin E deficiency is essentially nonexistent in people who eat food, and as a supplement it has failed nearly every large prevention trial ever run on it — including one that found more prostate cancer. The only defensible uses are niche: biopsy-proven NASH, and weakly, slowing functional decline in Alzheimer's.

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What the science says

  • Does not prevent cancer — and increased prostate cancer risk Limited evidence

    SELECT randomised 35,533 healthy men to 400 IU/day of synthetic alpha-tocopherol; with extended follow-up the vitamin E group had significantly MORE prostate cancer (HR 1.17, 99% CI 1.004-1.36, P=0.008), an absolute excess of about 1.6 cases per 1,000 person-years. No large trial has shown a cardiovascular or cancer benefit from vitamin E supplements.

  • High doses (400+ IU/day) may modestly increase all-cause mortality Limited evidence

    A dose-response meta-analysis of 19 trials (135,967 participants) found a pooled all-cause mortality risk difference of +39 per 10,000 people in trials using 400 IU/day or more (95% CI 3 to 74, P=0.035), with no excess at lower doses. The signal is contested and the trials were mostly in chronically ill populations — but with no demonstrated upside, there is nothing to offset it.

  • Improves liver histology in non-diabetic NASH Moderate evidence

    In the PIVENS trial (247 non-diabetic adults, 96 weeks), 800 IU/day of natural alpha-tocopherol improved NASH histology in 43% of patients versus 19% on placebo (P=0.001), with reductions in steatosis (P=0.005) and lobular inflammation (P=0.02) but no improvement in fibrosis. This is one good trial in one specific population, and it is why guidelines mention vitamin E at all.

  • May slightly slow functional decline in mild-to-moderate Alzheimer's Limited evidence

    TEAM-AD randomised 613 patients for a mean 2.3 years; 2,000 IU/day alpha-tocopherol slowed ADCS-ADL decline by 3.15 units versus placebo (95% CI 0.92-5.39), roughly 19% less functional loss. Memantine and the combination showed no benefit. A single trial, at a dose double the tolerable upper limit.

Dosage & safety

Studied doseRDA is 15 mg/day alpha-tocopherol — about 22 IU of natural d-alpha-tocopherol or 33 IU of synthetic dl-alpha-tocopherol. Trial doses far exceed this: 800 IU/day for NASH, 2,000 IU/day in the Alzheimer's trial, 400 IU/day in the failed prevention trials. Tolerable upper limit is 1,000 mg/day (about 1,500 IU natural). Natural d-alpha-tocopherol has roughly twice the bioavailability of the synthetic form; mixed tocopherol and tocotrienol products have essentially no clinical outcome data.
SafetyDoses of 400 IU/day and above are not benign: increased prostate cancer in SELECT, increased haemorrhagic stroke in ATBC and Physicians' Health Study II, and antiplatelet effects that raise bleeding risk. Clinically significant interactions with warfarin, DOACs, aspirin and clopidogrel; very high doses can also antagonise vitamin K-dependent clotting. Stop at least 2 weeks before surgery. Avoid in people with bleeding disorders or on anticoagulants without medical supervision. True deficiency is confined to fat-malabsorption syndromes, abetalipoproteinemia and rare genetic transport defects — not to ordinary diets.

How to take it

TimingTiming does not matter.
With food?With a meal containing fat — absorption is poor without one.
Worth knowingIf the label lists IU, 'd-alpha' is natural and about twice as potent as synthetic 'dl-alpha' — but the harms in trials appeared at 400 IU and above, so there is little reason to exceed the RDA at all.

Interactions

With medications

  • warfarin, DOACs, aspirin and clopidogrel

    Vitamin E has antiplatelet activity and at very high doses antagonises vitamin K-dependent clotting, raising bleeding risk. avoid doses above the RDA on these drugs, and stop at least 2 weeks before surgery

  • the statin plus niacin combination

    An antioxidant cocktail including vitamin E blunted the HDL rise from statin-niacin therapy in trial data. do not add high-dose vitamin E to lipid therapy

  • chemotherapy and radiotherapy

    High-dose antioxidants may interfere with treatments that work through oxidative damage; the question is unsettled. do not take supplemental doses during cancer treatment without oncology approval

  • orlistat and bile acid sequestrants

    Fat malabsorption reduces vitamin E uptake. separate by at least 4 hours

With other supplements

  • vitamin K

    Very high vitamin E doses antagonise vitamin K-dependent clotting factors. avoid high-dose vitamin E if you have any bleeding tendency

  • fish oil, garlic and ginkgo

    Additive antiplatelet effect. avoid stacking, particularly before surgery

Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.

Frequently asked questions

Is vitamin E worth taking as an antioxidant?

The evidence says no. Vitamin E has failed nearly every large prevention trial, and in SELECT, 400 IU/day of vitamin E led to significantly more prostate cancer. Deficiency is essentially nonexistent in people who eat food.

Is high-dose vitamin E dangerous?

Vitamin E at 400 IU/day and above is not benign: trials have linked it to more prostate cancer, haemorrhagic stroke and bleeding. A meta-analysis also found a small rise in all-cause mortality at those vitamin E doses.

Does vitamin E work for fatty liver disease?

The evidence is moderate and narrow: in one good trial of non-diabetic adults with NASH, 800 IU/day of vitamin E improved liver histology in 43% versus 19% on placebo, but not fibrosis. That niche is the main reason guidelines mention vitamin E.

Is vitamin E safe with blood thinners?

Avoid vitamin E doses above the RDA with warfarin, DOACs, aspirin or clopidogrel, because vitamin E raises bleeding risk. Stop vitamin E at least 2 weeks before surgery.

Scientific references

Where to buy

Swanson Vitamins, Vitamin E Mixed Tocopherols, 134 mg (200 IU), 100 Softgels

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