Vitamin supplements have beneficial and adverse effects depending on the dosage given and the age and sex of the recipient. Vitamin supplements have been extremely profitable in the health industry, but there is limited scientific data supporting vitamin supplement benefits. Many studies over the last decade have shown that vitamin supplements provide few health benefits and can lead to adverse effects, such as abnormal bone growth, birth defects, or an increased risk of cancer. Some researchers state that people with a specific vitamin deficiency should take vitamin supplements because the supplement can alleviate this deficiency. Many healthy people take vitamin supplements to prevent disease or have better health, but some researchers argue this is a misconception. Most health organizations indicate that consuming vitamins should be through diet, not supplements. The value of dietary supplements, most of which are consumed in developed countries, has been a controversial topic, because the beneficial effects of taking vitamin supplements is hotly contested. Many experts in the field of nutritional physiology suggest that Americans adequately receive enough vitamins in their diet and do not need to take vitamin supplements. Researchers at John Hopkins announced that the United States should stop spending money on vitamin supplements. Their research has found no benefits to taking vitamin supplements, because most people in industrialized areas are well-nourished. In this study, I have gathered that vitamin supplements are not beneficial when one has a sufficiently nutrient-rich diet; whereas, one who has a vitamin deficient diet can benefit from taking vitamin supplements. Furthermore, I have gathered that people older than 65-years-old should take vitamin B12 because vitamin B12 levels decrease with age. There is not enough evidence to prove or disprove that vitamin supplements are generally beneficial. In fact, I gathered that vitamin supplements may even be harmful. I propose that further studies should be conducted to discover the truth about the possible benefits of vitamin supplementation for healthy individuals and among people with different health conditions, activity levels, and nutrient requirements.