Published: 2 June 2022


Can Vitamin E cause bleeding?

Published 2 June 2022
Prescriber Update 43(2): 22–23
June 2022

Key messages

  • Although the data is limited, there are plausible mechanisms whereby vitamin E may cause bleeding:
    • the main oxidation product of alpha-tocopherol (a type of ingestible vitamin E) is tocopheryl quinone, which has anticoagulant properties
    • vitamin E may inhibit platelet aggregation.
  • The recommended daily intake of vitamin E is 10 mg for men and 7 mg for women. Exceeding the recommended dose could theoretically cause clinically significant bleeding.

The Centre for Adverse Reactions Monitoring (CARM) received a report of vitamin E toxicity. A patient experienced easy bruising after finishing a dietary supplement containing high levels of vitamin E.

Vitamin E

Vitamin E is a lipid-soluble antioxidant.1 It has an important role as a free radical scavenger to protect polyunsaturated fatty acids from oxidation.2,3 Humans cannot synthesise vitamin E and must ingest it from the diet, primarily from fats and oils.2,4 Olive and sunflower oils have high levels of alpha-tocopherol, the primary bioactive form of vitamin E.2,4

The recommended daily intake of vitamin E (as alpha-tocopherol equivalents) for adults in New Zealand is 10 mg for men and 7 mg for women.3,4


There are biologically plausible mechanisms whereby vitamin E may cause bleeding. Tocopheryl quinone is an oxidised form of alpha-tocopherol with anticoagulant activity.4,5 It can interfere with vitamin K metabolism, theoretically causing bleeding.5 Vitamin E may also inhibit platelet aggregation.2,6 However, there is limited data to support high vitamin E levels causing bleeding, and the clinical significance of high vitamin E levels is also unknown.

In the case report mentioned above, the product ingested contained about 30 times the recommended daily intake of Vitamin E. The side effects also occurred within a plausible time frame. Consideration should be given to the theoretical possibility of vitamin E as a cause of bleeding.

Further information

The Medicines Adverse Reactions Committee discussed this topic at the 188th meeting in December 2021. For further information, see the meeting minutes and meeting report.


  1. Loh HC, Lim R, Lee KW, et al. 2021. Effects of vitamin E on stroke: a systematic review with meta-analysis and trial sequential analysis. Stroke and Vascular Neurology 6(1): 109-120. DOI: 10.1136/svn-2020-000519 (accessed 11 April 2022).
  2. Pazirandeh S, Burns DL. 2020. Overview of vitamin E. In: UpToDate 28 October 2020. URL: (accessed 13 November 2021).
  3. Health Navigator New Zealand. 2021. Role of vitamins 3 July 2021. URL: (accessed 19 April 2022).
  4. Australian Government National Health and Medical Research Council and New Zealand Ministry of Health. 2014. Nutrient Reference Values for Australia and New Zealand. URL: (accessed 19 April 2022).
  5. Dowd P and Zheng ZB. 1995. On the mechanism of the anticlotting action of vitamin E quinone. Proceedings of the National Academy of Sciences of the United States of America 92(18): 8171-5. DOI: 10.1073/pnas.92.18.8171 (accessed 11 April 2022).
  6. Schurks M, Glynn RJ, Rist PM, et al. 2010. Effects of vitamin E on stroke subtypes: meta-analysis of randomised controlled trials. BMJ 341: c5702. DOI: 10.1136/bmj.c5702 (accessed 11 April 2022).
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