Quick answer

Vitamin E from food has not been found to cause harm. The concerns are about supplements: high doses might increase bleeding by slowing clotting, so adults have an upper limit of 1,000 mg a day. Some trials found problems at far lower doses, such as 180 mg a day. Vitamin E on the skin can cause rashes.^1,2,3

Key facts

The 1,000 mg limit equals 1,500 IU of natural or 1,100 IU of synthetic vitamin E a day.¹
The limit rests on limited data: small groups taking up to 3,200 mg a day for only weeks or months.²
In one small trial, about a third of the people who put vitamin E ointment on a surgical scar reacted to it.⁴
Vitamin E in food has not been linked to harm and does not need to be limited.¹

Bleeding

High doses of vitamin E supplements might increase the risk of bleeding, by reducing the blood's ability to clot after a cut or injury, and of serious bleeding in the brain (hemorrhagic stroke).^1,2

Two trials found more hemorrhagic strokes in people taking vitamin E: Finnish male smokers taking 50 mg a day for about 6 years, and US male doctors taking 400 IU (180 mg) of synthetic vitamin E every other day for 8 years, most of whom also took aspirin.²

Both trials used amounts well under the upper limit: 50 mg a day in one and 400 IU (180 mg) every other day in the other. Because most of the doctors in the second trial also took aspirin, NIH says the result could point to a tendency of vitamin E to cause bleeding.²

Ask your pharmacist or doctor first

Vitamin E can slow the clumping of platelets and work against the clotting factors that depend on vitamin K. Taking large doses with an anticoagulant or antiplatelet medicine, such as warfarin, can therefore increase the risk of bleeding, especially when vitamin K intake is low. NIH says the amount needed to cause a clinically significant effect is not known.^1,2

Expected from how the two work, not shown in studies

Long-term use of high doses

In the SELECT trial of 35,533 healthy men aged 50 and over, those who had taken 400 IU (180 mg) of synthetic vitamin E a day had a 17% higher risk of prostate cancer than men on placebo, a difference that showed up with 1.5 years of extra follow-up.^1,2

Two meta-analyses linked high-dose vitamin E supplements to a small rise in deaths from any cause, beginning at about 150 IU a day in one. NIH says the meaning is unclear, because most participants were middle-aged or older with long-term illnesses, and a review of studies in healthy people found no convincing increase.²

In the HOPE-TOO trial of people aged 55 and over with heart disease or diabetes, those who took 400 IU (268 mg) of natural vitamin E a day for about 7 years were 13% more likely to develop heart failure and 21% more likely to be hospitalized for it, a finding not reported in other large studies.²

These findings come from doses many times the recommended 15 mg a day, often taken for years, and they are the reason to ask a doctor before taking a high-dose vitamin E supplement. Vitamin E in food has not been found to cause harm.^1,2

Side effects on the skin

Vitamin E applied to the skin can cause allergic contact dermatitis. Of 38,699 people patch tested in North America from 2001 to 2016, 0.9% reacted to it, most often from moisturizers and other personal care products.³

In a small double-blind trial, 5 of 15 people who put vitamin E ointment on a surgical scar developed contact dermatitis, and the scars looked no better than with plain ointment.⁴

A 2016 review of six scar studies found two that reported contact dermatitis, itching or rash, and judged the evidence too weak to justify routine use of vitamin E alone on scars. If a vitamin E cream or oil leaves your skin red or itchy, stop using it and show the product to a doctor or pharmacist.⁵

Taking it every day

The risks NIH describes come from high-dose supplements, often 400 IU daily or every other day for years, while a once-daily multivitamin typically holds about 13.5 mg. If you take a separate vitamin E supplement every day, ask your doctor whether you need it.^1,2

Medicines

Besides blood thinners, NIH names two situations to discuss with a doctor: chemotherapy or radiotherapy, where antioxidant supplements might change how well the treatment works, and a statin taken with niacin, where an antioxidant mix that included vitamin E blunted the expected rise in HDL cholesterol. The orlistat label reports that orlistat cut the absorption of a vitamin E supplement by about 60%.^1,2,6

Who should ask first

People taking a blood thinner or an antiplatelet medicine
People having chemotherapy or radiotherapy
Anyone with a bleeding disorder
Anyone pregnant or breastfeeding who is considering more than a multivitamin's amount
Men considering 400 IU a day or more, the dose used in the SELECT trial²

Questions people ask

Can I take vitamin E every day?

Daily intake is how the recommended 15 mg is meant to be met, and vitamin E from food has not been found to cause harm. Daily high-dose supplements are another matter, so ask your doctor before taking more than a multivitamin's amount.^1,2

Does vitamin E thin your blood?

It can slow the clumping of platelets and work against clotting factors that depend on vitamin K, which is why high doses might increase bleeding, especially with blood thinners. NIH says the amount needed for a clinically significant effect is not known.²

What are the side effects of vitamin E for men?

Two large trials in men raised concerns: more prostate cancer with 400 IU of synthetic vitamin E a day in SELECT, and more bleeding strokes in male doctors taking 400 IU every other day, most of whom also took aspirin.²

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Sources

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.