The evidence from large randomised trials is consistently negative: vitamin E supplements offer no protection against cardiovascular disease, cancer, or mortality, and the USPSTF formally advises against them. Added to this is a serious safety signal for an increased risk of brain bleeds. Small studies in Alzheimer's disease and skin conditions provide weak and unconfirmed indications at best, and the Alzheimer's research used a combination product, meaning the effect of vitamin E in isolation cannot be separated out. For the average adult, there is no good reason to supplement with vitamin E.
Large randomised trials show that vitamin E supplements do nothing against the most feared diseases. Based on nine large randomised trials involving more than 107,000 participants, there is no demonstrable benefit for the risk of cardiovascular disease, cancer, or mortality from any cause. The all-cause mortality risk ratio was 1.02, the cardiovascular disease risk ratio was 0.96, and the cancer risk ratio was 1.02. All outcomes are statistically non-significant. The U.S. Preventive Services Task Force (USPSTF) has, on the basis of this evidence, issued a formal 'D recommendation': vitamin E is actively discouraged for the prevention of cardiovascular disease or cancer, with moderate certainty that there is no net benefit whatsoever.
There are indications of a possible safety risk. The same large trial analysis1 produces a signal suggesting that vitamin E supplementation may be associated with an increased risk of a brain bleed (haemorrhagic stroke). The exact magnitude of this risk has not been precisely quantified in the available data, but the signal is serious enough to take seriously, particularly in people who also use blood thinners.
In Alzheimer's disease, one small randomised trial was found that reported positive effects on behavioural symptoms and daily functioning in patients. However, this involved a combination product of carotenoids, omega-3 fatty acids, and vitamin E all at once. Which component is responsible for any effect cannot be established on the basis of this study. This therefore does not constitute evidence that vitamin E works on its own in Alzheimer's disease.
A scoping review examined what is known about vitamin E deficiency during pregnancy and the brain development of the child. An association with poorer cognitive development and brain volume problems was found. This says something about the importance of adequate dietary intake during pregnancy, but it is not an argument for additional supplementation on top of a normal intake. The finding is moreover associational, not evidence of cause and effect.
For the skin, there are modest indications from a narrative review that vitamin E may be beneficial in conditions such as atopic dermatitis and in protection against UV damage. However, the quality of the evidence is limited, there is no clear consensus dosage, and hard quantitative results are lacking. In polycystic kidney disease (ADPKD), clinical benefit is uncertain and supplementation is not recommended due to lack of evidence.
Based on 9 large RCTs (>107,000 participants) for heart disease/cancer, a formal USPSTF recommendation, one small Alzheimer's RCT using a combination supplement, and narrative/scoping reviews for skin and pregnancy. PMIDs: 35727272, 36480969, 35727271, 35180821, 34684531, 38256329, 37729939.