We study dynamical symmetry breaking in the top-mode standard model in the large-Nclimit and for the case of one Higgs doublet Φ. We derive the 1-loop effective potential Veff(Φ) in the massless case and the condition for the minimum which is the gap equation. Around this minimum, we can define the complete lagrangian as the sum of tree plus induced terms and study its properties. Corrections to the familiar Veff(Φ) in the standard model and to the ratio MHiggs/mtopare computed and discussed. © 1993.