What are the side effects of excessive vitamin E?

December 31, 2025 •

3 min read

While vitamin E is a necessary nutrient and potent antioxidant, the National Institutes of Health has established an upper intake limit of 1,000 mg (1,500 IU) per day for adults to avoid health complications. Excessive amounts of vitamin E, typically from high-dose supplements, can cause side effects ranging from mild to severe.

Quick Summary

Overconsumption of vitamin E, usually through high-dose supplements, can lead to adverse health effects. Key concerns include an increased risk of bleeding, gastrointestinal distress, fatigue, and potential long-term complications, including an elevated risk of certain cancers.

Key Points

Increased Bleeding Risk: Excessive vitamin E, especially from high-dose supplements, can interfere with blood clotting and increase the risk of bleeding.
Gastrointestinal Distress: Nausea, diarrhea, stomach cramps, and general digestive upset are common short-term side effects of excess vitamin E.
Neurological Symptoms: Headaches, dizziness, and blurred vision can occur with high vitamin E intake.
Potential Cancer Link: Some studies, like the SELECT trial, have linked long-term, high-dose vitamin E supplementation to an increased risk of prostate cancer in men.
Toxicity is Supplement-Related: It is nearly impossible to consume excessive vitamin E from food sources alone; toxicity is almost always caused by supplements.
Consult a Doctor: Individuals on blood thinners or with other medical conditions should be particularly cautious and consult a healthcare provider before taking vitamin E supplements.
Tolerable Upper Limit: The recommended upper intake limit for adults from supplements is 1,000 mg (1,500 IU) per day, but risks may still exist below this level.

Understanding Vitamin E Toxicity

Vitamin E is a fat-soluble antioxidant, meaning it is stored in the body's fat tissues rather than being excreted through urine. Excessive intake, particularly through supplements, can lead to a buildup and toxicity known as hypervitaminosis E. Toxicity from food is rare; high-dose supplements are a common cause. The tolerable upper intake level (UL) for adults is 1,000 mg (approximately 1,500 IU) daily. Consistently exceeding this can lead to side effects.

Short-term side effects

Immediate side effects of excessive vitamin E often involve gastrointestinal and neurological symptoms. While typically not life-threatening, they indicate a need to reduce intake.

Common short-term symptoms include:

Gastrointestinal Distress: Nausea, diarrhea, and stomach cramps are frequently reported symptoms.
Fatigue and Weakness: Unusual tiredness or muscle weakness may occur.
Headaches and Dizziness: Some individuals experience headaches or dizziness.
Blurred Vision: Visual disturbances have been linked to higher doses.

The risk of bleeding (coagulopathy)

Increased bleeding risk is one of the most serious side effects of excessive vitamin E. Vitamin E can thin the blood by interfering with vitamin K, which is vital for clotting. This risk is particularly dangerous for certain groups.

Serious bleeding risks are heightened for:

Individuals on anticoagulant medications.
Those with vitamin K deficiency.
People undergoing or recovering from surgery.

Severe bleeding, including hemorrhagic strokes, has been reported with excessive intake. Adhering to recommended dosages is crucial.

Long-term health concerns

Long-term excessive vitamin E intake has been linked to other serious health issues. Research has explored the connection between prolonged, high-dose supplementation and an increased risk of specific problems.

Potential long-term risks include:

Increased All-Cause Mortality: Some studies suggest a link between high-dose vitamin E (≥400 IU/day) and increased death risk, though results vary.
Prostate Cancer Risk: The SELECT trial found a higher incidence of prostate cancer in healthy men taking high-dose vitamin E supplements (400 IU daily) over several years.

Comparison of Normal vs. Excessive Vitamin E Effects


Feature	Normal Vitamin E Intake	Excessive Vitamin E Intake
Bleeding Risk	Negligible; supports healthy blood vessel function.	Significantly increased risk due to interference with vitamin K and impaired clotting.
Gastrointestinal Effects	No adverse effects; assists in overall digestive health.	Nausea, diarrhea, abdominal cramps, and general GI upset.
Fatigue/Weakness	No effect on energy levels.	Increased fatigue and generalized muscle weakness.
Neurological Effects	No adverse effects.	Headaches, dizziness, and blurred vision.
Toxicity	Minimal risk, as excess is not stored to harmful levels.	Fat-soluble storage leads to accumulation and potential toxicity.

How to prevent vitamin E toxicity

Preventing vitamin E toxicity involves moderation. The best way is to get vitamin E from a balanced diet rich in nuts, seeds, and leafy greens. Dangerous levels are nearly impossible from food alone.

If considering supplements, consult a healthcare provider for dosage guidance. If taking high doses, your doctor may recommend reducing or stopping, especially if you use blood thinners or have other health conditions. Store supplements safely away from children.

Conclusion

While essential, excessive vitamin E from high-dose supplements carries significant risks. Side effects range from GI upset and fatigue to increased bleeding and potential long-term cancer risk. By understanding these dangers and focusing on dietary sources, you can benefit from vitamin E without toxicity risks. Always consult a healthcare professional before starting new high-dose supplements. For more information, see authoritative sources like the National Institutes of Health.

Frequently Asked Questions

No, it is extremely difficult to consume a dangerously high dose of vitamin E from food sources alone. Toxicity is almost always associated with high-dose supplementation.

The tolerable upper intake level (UL) for vitamin E from supplements in adults is 1,000 mg per day. This is approximately 1,500 IU of natural vitamin E or 1,100 IU of synthetic vitamin E.

Excessive vitamin E can interfere with the function of vitamin K, a critical nutrient for blood clotting. This interaction reduces the body's ability to form clots, increasing the risk of bleeding and bruising.

Early signs of overdose often include gastrointestinal issues such as nausea, diarrhea, and stomach cramps, along with general fatigue, weakness, headaches, or blurred vision.

Yes, due to its blood-thinning properties, you should inform your doctor and likely stop taking vitamin E supplements at least two weeks before any scheduled surgery.

Some long-term studies, like the SELECT trial, have shown an increased risk of prostate cancer in men taking high doses of synthetic vitamin E. More research is needed, but the finding raises significant concerns.

Yes, high-dose vitamin E supplements can interact with blood thinners like warfarin and aspirin, as well as some chemotherapy drugs, which can lead to complications.