Nucleotides are the building blocks of DNA and RNA. Nucleotides are molecules guanosine and cystosine together pair up and called as purines. Adenosine and thymidine pair up together called as pyrimidines. They are involved in almost all activities in cell. They are essential for proper functioning of immune system. Stress increases the need for nucleotides. Nucleotides are essential in replacing and repairing cells. Nucleotides increases HDL which is a good cholesterol. Decrease in the concentration of LDL cholesterol. It accelerated antibody production. Nucleotides help in increase of white blood cells and number of macrophages. Nucleotide helps in faster recovery of liver after injury. Nucleotides increase interleukin 2 production.