Nα-alkylated amino acids and peptides are denoted in a slightly different manner:

e.g. N-Me-Ile-OH (not Me-Ile-OH nor H-MeIle-OH), Sar-OH (not H-Sar-OH),

Boc-N-Me-Phe-N-Me-Phe-OH

Cα-methylated amino acids are designated likewise:
e.g. H-α-Me-Phe-OH