Cationic helical peptides play a crucial role in applications such as anti-microbial and anti-cancer activity. The activity of these peptides directly correlates with their helicity. In this study, we have performed extensive all-atom molecular dynamics simulations of 25 Lysine-Leucine co-polypeptide sequences of varying charge density ( λ ) and patterns. Our findings showed that an increase in the charge density on the peptide leads to a gradual decrease in the helicity up to a critical charge density λ c . Beyond, λ c a complete helix to coil transition was observed. The decrease in the helicity correlated with the increased number of water molecules in first solvation shell, solvent-exposed surface area, and a higher value of the radius of gyration of the peptide.