Headaches are a mild side effect, but repeated headaches and migraines resulting from taking vitamins may evolve into a serious problem. If you notice your vitamins and supplements causing headaches, it could be a sign of acute vitamin toxicity from megadosing.

Can certain supplements cause headaches?

Multivitamins that offer large amounts of fat-soluble vitamins can be harmful, as excess levels of these vitamins can build up in the body. For instance, excess intakes of vitamin A may cause headaches, liver damage, weaker bones, and birth defects ( 11 ).

What are the side effects of taking supplements?

However, because they contain active ingredients, they can also cause unwanted effects, such as elevated blood pressure, racing or irregular heartbeat, headache, dizziness, or digestive symptoms.