negatively regulates negative regulation of macromolecule biosynthetic process hemoglobin biosynthetic process regulation of hemoglobin biosynthetic process negative regulation of hemoglobin biosynthetic process GO:0046986 down regulation of hemoglobin biosynthetic process down-regulation of hemoglobin biosynthetic process negative regulation of haemoglobin biosynthesis negative regulation of hemoglobin synthesis biological_process negative regulation of hemoglobin biosynthesis negative regulation of hemoglobin anabolism Any process that stops, prevents, or reduces the frequency, rate or extent of the chemical reactions and pathways resulting in the formation of hemoglobin, an oxygen carrying, conjugated protein containing four heme groups and globin. negative regulation of hemoglobin formation inhibition of hemoglobin biosynthetic process downregulation of hemoglobin biosynthetic process negative regulation of haemoglobin biosynthetic process negative regulation of protein metabolic process biological regulation