Garden of Life and Optimum Nutrition are two well-known vitamin manufacturers as of 2015. Whereas Garden of Life produces vitamin supplements for the general public, Optimum Nutrition focuses on athletes and sports enthusiasts.
As the vitamin needs of an individual depend on their gender, both companies offer separate products for men and women. For instance, men need greater amounts of vitamin C to stay healthy. On the other hand, women need more than double the amount of iron men need. As such, women's vitamin products often include iron as well.
Taking vitamin D supplements is crucial in winter months. The natural way for the human body to get vitamin D is through skin exposure to sunlight. When the weather makes is impossible to get enough vitamin D from the sun, consider taking vitamin D supplements to make up for the lack of sunlight.