All vitamins are important. But as a man, your health issues are different than a woman's, so your need to focus on getting certain vitamins is critical. Getting an injection that combines vitamin C and a vitamin B complex is ideal. Vitamin C and folic acid, a B vitamin, are needed for heart health, while niacin, another B vitamin, is important for helping with erectile dysfunction problems. An injection gives you plenty of these vitamins all in one convenient dose. 

Vitamin C

Data gathered by the Centers for Disease Control and Prevention in 2012 concluded that men were more likely than women to be deficient in vitamin C. Approximately 7 percent of adult men in the United States have poor vitamin C intakes. Vitamin C does more than power white blood cells that keep you healthy. It improves nitric oxide production.

Nitric oxide is a gas your body produces that's responsible for delivering messages from cell to cell. But nitric oxide is also essential for your heart health because it regulates blood circulation, protects heart tissues from damaging free radicals and helps prevent plaque buildup in your arteries.  The Food and Nutrition Board of the Institute of Medicine states that men need 90 milligrams of daily vitamin C. You'll also need an extra 35 milligrams if you smoke.  

Folic Acid

Folic acid is the supplemental form of folate, another B vitamin. Researchers evaluated folic acid and its effect on biomarkers that impact inflammation in men and published their results in the 2013 edition of "The FASEB Journal." Reducing inflammation in your body is critical for lowering your risk of developing chronic diseases, including heart disease.

By giving participants 400 micrograms of folic acid daily, which meets the recommendation, researchers noted that folic acid levels went up after 12 weeks. This brought homocysteine -- in inflammatory-causing amino acid -- levels down, as well as decreased other biomarkers that cause inflammation.

Niacin

Niacin, a type of B vitamin, could be beneficial for resolving erectile dysfunction problems, according to 2011 research published in "The Journal of Sexual Medicine." Research participants were given daily niacin supplementation of up to 1,500 milligrams a day, which is much higher than the recommendation of just 16 milligrams a day.

At the end of the study, participants were asked to rank their erectile functions based on a standardized questionnaire. Researchers compared those responses to the baseline responses. They found that for those who reported having moderate to severe erectile dysfunction, niacin supplements drastically improved symptoms. The same benefits were not observed in participants with only mild issues with erectile dysfunction though.

Always go over proper dosages with your doctor first. While vitamin injections through a company like Metabolix Wellness are safe and have very few side effects, they might interact poorly with your prescription medications.