SSRIs

• Both a severe excess and a severe lack of serotonin can serve to repress libido. Nearly all selective serotonin reuptake inhibitors, or SSRIs, such as Lexapro, Prozac and Paxil, can decrease libido in both men and women.
  
  

Decreased Dopamine

• Dopamine is involved with the male and female sex drives. Dopamine is created from two amino acids, phenyalnine and tyrosine. These are found in milk, cheese, almonds, bananas and fish. It may be the case that by cutting back on these foods, dopamine production may also be cut. However, it is likely that a decrease in dopamine production can be problematic for an individual's mood.
  
  

Calcitriol

• Calcitriol has the occasional side effect of reducing sex drive. Calcitriol is a form of vitamin D that helps people with calcium deficiencies due to kidney malfunction. At the present time, however, there is no off-label use of calcitriol to control sexual urges.
  
  

B Vitamin Deficiency

• It is possible that decreasing the intake of B vitamins can also decrease sexual desire. The connection of energy levels to B12 is well known. In general, chemicals that produce an "upper" effect also heighten libido. Therefore, cutting back on these supplements may decrease it.
  
  

Low Levels of Zinc

• Decreasing zinc intake may repress sexual urges. Zinc is an aphrodisiac and is required for testosterone production. It is normally found in seafood and certain leafy vegetables or taken as a supplement. If you are trying to decrease sexual desire, try avoiding seafood and shellfish.