Coenzyme Q10 is a compound that is made naturally in the body. The body uses it for cell growth and to protect cells from damage that could lead to cancer (see Question 1).
In 3 small studies of coenzyme Q10 in breast cancer patients, some patients appeared to be helped by the treatment. Weaknesses in study design and reporting, however, made it unclear if benefits were caused by the coenzyme Q10 or by something else (see Question 6).
Coenzyme Q10 may not mix safely with other treatments. It is important that patients tell their health care providers about all therapies they are currently using or thinking of using (see Question 7).