Many medical papers demonstrate coenzyme Q's usefulness as a preventive as well as a treatment. In general, coenzymes work with enzymes to help them in their various biochemical functions.
Coenzymes are smaller than proteins, and so can survive digestion and pass into the system.
Coenzyme Q was approved in Japan in 1974 to treat congestive heart failure, and has also been approved in Sweden, Italy, Denmark, and Canada. Some people say coenzyme Q increases aerobic endurance, but more studies are needed to verify this. I often recommend it to help stabilize blood sugar in people who have diabetes, and to slow heart disease. It also maintains the health of gums and other tissues. There is evidence that coenzyme Q can prolong survival in women with breast cancer, too.