Vitamin E has been shown to be safe and free from any adverse side-effects in multiple studies, even in dosages of 1200 IU daily.

See:

The safety of high-dose vitamin E supplementation in healthy Japanese male adults.

...a high dose of vitamin E for 28 d [1,200 IU] had no adverse effects in healthy men.

Assessment of the safety of supplem...ts of vitamin E in healthy older adults.

...4 mo of supplementation with 60-800 IU vitamin E/d had no adverse effects.

Assessment of the safety of high-do... with vitamin E in healthy older adults.

...short-term supplementation with 800 mg vitamin E/d has no adverse effect on healthy older adults.