It is shown that an FC-nilpotent group G = AB = AK = BK which is the p
roduct of two hypercentral subgroups A and B and a nilpotent normal su
bgroup K of G is hypercentral. This implies that if the FC-nilpotent g
roup G = AB is the product of a proper nilpotent subgroup A and a prop
er hypercentral subgroup B then A or B is contained in a proper normal
subgroup of G.