Can high doses of vitamin E be harmful?

Upper limits

The US upper limit is 1,000 mg a day of vitamin E from supplements for adults. That is 1,500 IU of the natural form or 1,100 IU of the synthetic form.^[1] For children it is 200 mg at 1 to 3 years, 300 mg at 4 to 8 years, 600 mg at 9 to 13 years and 800 mg at 14 to 18 years.^[1]

The EU upper limit is lower: 300 mg a day from all sources for adults, also in pregnancy and when breastfeeding. For children it goes from 100 mg at 1 to 3 years to 260 mg at 15 to 17 years. EFSA reviewed the evidence again in 2024 and kept these limits.^[6]

Both limits are set to avoid bleeding, because high doses of vitamin E can slow blood clotting.^[1][6] No harm has been found from vitamin E in food.^[1]

Bleeding and stroke

• A 2010 review of 9 trials with 118,765 people found 22% more hemorrhagic strokes with vitamin E. That is 1 extra case for every 1,250 people who take it.^[2]
• A 2024 review of 16 trials found more hemorrhagic strokes only when vitamin E was taken with other antioxidants, not when it was taken alone.^[7]
• In the Physicians' Health Study II, 400 IU every other day for 8 years raised the risk of hemorrhagic stroke by 74%.^[8]
• A Finnish trial in male smokers found more hemorrhagic strokes with 50 mg a day, taken for about 6 years.^[1]

Prostate cancer

In the SELECT trial, 35,533 healthy men took 400 IU of synthetic vitamin E a day, selenium, both, or a placebo. Men who took vitamin E alone had a 17% higher risk of prostate cancer: 1.6 extra cases for every 1,000 men each year.^[3]

Heart failure

In HOPE and HOPE-TOO, people with vascular disease or diabetes took 400 IU of natural vitamin E a day. They had a 13% higher risk of heart failure and a 21% higher risk of a hospital stay for it.^[9]

Death from any cause

The reviews disagree. A 2005 review of 19 trials found 39 more deaths per 10,000 people at doses of 400 IU a day or more, and the risk began to rise above 150 IU a day.^[4] Its authors noted that these trials were often small and in people with chronic diseases.^[4] Later reviews found no effect on death. A 2011 review of 57 trials found none at doses up to 5,500 IU a day.^[5] A 2014 review of 18 trials in healthy people found none,^[10] and neither did the 2022 review for the US Preventive Services Task Force.^[11]

Pregnancy and preterm babies

A 2015 Cochrane review included 21 trials with 22,129 pregnant women. Vitamin E was given with vitamin C or other supplements. It did not change the risk of stillbirth, pre-eclampsia, preterm birth or poor growth of the baby. Placental abruption, when the placenta comes away too early, was less common, and the authors called for more research.^[12] Women who took vitamin E had more abdominal pain. Their waters were also more likely to break at term before labour started.^[12] In preterm babies, vitamin E lowered the risk of bleeding in the brain but raised the risk of sepsis, a severe infection.^[13]

Medicines

Vitamin E can interact with:

• blood thinners and medicines against platelets, such as warfarin: more risk of bleeding, probably at more than 400 IU a day^[1]
• simvastatin with niacin: antioxidants that included vitamin E blunted the rise in HDL cholesterol^[1]
• chemotherapy and radiotherapy: antioxidants might make these treatments work less well^[1]

People who take medicines every day should ask a doctor or pharmacist before they take vitamin E.^[1]